Patent US1643586A successfully refreshed from Google Patents.
Patent US4585957A successfully refreshed from Google Patents.
US4585957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diode load emitter coupled logic circuits
Assignee: Motorola Solutions Inc
•
Filing: 1983-04-25
•
Granted: 1986-04-29
•
Expires: 2003-04-25
Abstract
Abstract Diode load emitter coupled logic circuits is described that utilizes forward biased diodes in the load circuits. The load circuits may be comprised of a single diode or two or more diodes connected in series. If a single diode is used in the load circuits, the slope factor of the diode must be greater than or equal to the slope factor of switching transistors in the logic circuit. External bias circuitry provides a bias current which can be varied for varying the frequency of operation of the logic circuit. High speeds at low power dissipations can be obtained since the switching transistors in the logic circuits do not switch completely on and off.
Inventors
- 👤 William J. Ooms
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:07
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/02; H03K19/08; H03K19/082; H03K19/086; H03K19/0866; H03K19/01; H03K19/013; H03K3/00; H03K3/02; H03K3/26; H03K3/28; H03K3/281; H03K3/286; H03K3/288; H03K3/2885; H03K3/289
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
157 words
A gating circuit responsive to first and second complementary input signals from a signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; means coupled to the emitter terminals of the first and second switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 2
Dependent Claim
157 words
A gating circuit responsive to first and second complementary input signals from a signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; means coupled to the emitter terminals of the first and second switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 3
Dependent Claim
31 words
The circuit according to claim 1, wherein said bias current generating means includes means for varying the generated bias current in response to a control signal from a control signal source.
Claim 4
Dependent Claim
213 words
A gating circuit responsive to first and second complementary input signals from a first signal source and third and fourth complementary input signals from a second signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said third and fourth input signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the first and second switching transistors and the output terminal of the second switching transistor, respectively; means coupled to the emitter terminals of the third and fourth switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 5
Dependent Claim
213 words
A gating circuit responsive to first and second complementary input signals from a first signal source and third and fourth complementary input signals from a second signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said third and fourth input signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the first and second switching transistors and the output terminal of the second switching transistor, respectively; means coupled to the emitter terminals of the third and fourth switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 6
Dependent Claim
31 words
The circuit according to claim 3, wherein said bias current generating means includes means for varying the generated bias current in response to a control signal from a control signal source.
Claim 7
Dependent Claim
256 words
A gating circuit responsive to first and second complementary input signals from a first signal source and third and fourth complementary input signals from a second signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals coupled to the collector terminals of the second and first switching transistors, respectively; fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said third and fourth input signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the first and second switching transistors and the intercoupled emitter terminals of the third and fourth switching transistors, respectively; means coupled to the emitter terminals of the fifth and sixth switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 8
Dependent Claim
256 words
A gating circuit responsive to first and second complementary input signals from a first signal source and third and fourth complementary input signals from a second signal source for generating first and second complementary output signals, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals coupled to the collector terminals of the second and first switching transistors, respectively; fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said third and fourth input signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the first and second switching transistors and the intercoupled emitter terminals of the third and fourth switching transistors, respectively; means coupled to the emitter terminals of the fifth and sixth switching transistors for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 9
Dependent Claim
31 words
The circuit according to claim 5, wherein said bias current generating means includes means for varying the generated bias current in response to a control signal from a control signal source.
Claim 10
Dependent Claim
257 words
A gating circuit having first and second complementary output signals for storing first and second complementary input signals from a first signal source in response to first and second complementary strobe signals from a second signal source, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first output signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second strobe signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; means coupled to the emitter terminals of the fifth and sixth switching transistorss for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 11
Dependent Claim
257 words
A gating circuit having first and second complementary output signals for storing first and second complementary input signals from a first signal source in response to first and second complementary strobe signals from a second signal source, said circuit comprising: first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first output signals, respectively, and collector terminals providing said first and second output signals, respectively; third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second strobe signals, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; means coupled to the emitter terminals of the fifth and sixth switching transistorss for generating a predetermined bias current; and first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal.
Claim 12
Dependent Claim
30 words
The circuit according to claim 7, wherein said bias current generating means includes for varying the generated bias current in response to a control signal from a control signal source.
Claim 13
Dependent Claim
602 words
A flip-flop circuit having first and second complementary flip-flop output signals for storing first and second complementary flip-flop input signals from a first signal source in response to first and second complementary clock signals from a second signal source, said circuit comprising: (a) master and slave circuit means, each having first and second complementary input signals and first and second complementary output signals, the first and second slave output signals providing the first and second flip-flop output signals, respectively, the first and second master input signals being coupled to the first and second flip-flop input signals, respectively, and the first and second slave input signals being coupled to the second and first master output signals, respectively; (b) said master circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first master output signals, respectively, and collector terminals providing said first and second master output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second master input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; (c) said slave circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first slave output signals, respectively, and collector terminals providing said first and second slave output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second slave input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between the power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; and (d) means coupled to the emitter terminals of the fifth and sixth switching transistors in the master and slave circuit means for generating a predetermined bias current.
Claim 14
Dependent Claim
602 words
A flip-flop circuit having first and second complementary flip-flop output signals for storing first and second complementary flip-flop input signals from a first signal source in response to first and second complementary clock signals from a second signal source, said circuit comprising: (a) master and slave circuit means, each having first and second complementary input signals and first and second complementary output signals, the first and second slave output signals providing the first and second flip-flop output signals, respectively, the first and second master input signals being coupled to the first and second flip-flop input signals, respectively, and the first and second slave input signals being coupled to the second and first master output signals, respectively; (b) said master circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first master output signals, respectively, and collector terminals providing said first and second master output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second master input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; (c) said slave circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first slave output signals, respectively, and collector terminals providing said first and second slave output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second slave input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between the power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; and (d) means coupled to the emitter terminals of the fifth and sixth switching transistors in the master and slave circuit means for generating a predetermined bias current.
Claim 15
Dependent Claim
31 words
The circuit according to claim 9, wherein said bias current generating means includes means for varying the generated bias current in response to a control signal from a control signal source.
Claim 16
Dependent Claim
947 words
A dual modulus dividing circuit for dividing first and second complementary clock signals from a clock signal source to generate first and second complementary output signals related to the first and second clock signals by a first modulus and a second modulus in response to the first and second complementary modulus control signals from a control signal source, said dividing circuit comprising: (a) first and second flip-flop circuits each including master and slave circuit means and each having first and second complementary flip-flop output signals for storing first and second complementary flip-flop input signals in response to the first and second complementary clock signals, the first and second output signals of the first flip-flop circuit being coupled to the first and second input signals of the second flip-flop circuit, respectively, the first and second output signals of the second flip-flop circuit coupled to the second and first input signals of the first flip-flop circuit, respectively, and said master and slave circuit means each having first and second complementary input signals and first and second complementary output signals, the first and second slave output signals providing the first and second flip-flop output signals, respectively, the first and second master input signals being coupled to the first and second flip-flop input signals, respectively, and the first and second slave input signals being coupled to the first and second master output signals; (b) said master circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first master output signals, respectively, and collector terminals providing said first and second master output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second master input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; (c) said slave circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first slave output signals, respectively, and collector terminals providing said first and second slave output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second slave input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between the power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; and (d) means coupled to the emitter terminals of the fifth and sixth switching transistors in the master and slave circuit means in the first and second flip-flop circuits for generating a predetermined bias current; and (e) a modulus control circuit coupled to a modulus control signal from a control signal source and being interposed between the intercoupled emitter terminals of the third and fourth switching transistors in the master circuit means in the first flip-flop circuit and the collector terminal of the fifth switching transistor in the master circuit means in the first flip-flop circuit, said modulus control circuit including seventh, eighth and ninth switching transistors each having base terminals, collector terminals and emitter terminals, the emitter terminals being intercoupled to one another, the base terminals of the seventh and eighth switching transistors being coupled to the first and second slave output signals in the first flip-flop circuit, the base terminal of the ninth switching transistor being coupled to the modulus control signal, the collector terminals of the seventh and ninth switching transistors being coupled to the intercoupled emitter terminals of the third and fourth switching transistors in the master circuit means in the first flip-flop circuit, the collector terminal of the eighth switching transistor being coupled to the collector terminal of the fourth switching transistor in the master circuit means in the first flip-flop circuit, and the emitter terminals of the seventh, eighth and ninth switching transistors being coupled to the collector terminal of the fifth switching transistor in the master circuit means in the first flip-flop circuit.
Claim 17
Dependent Claim
947 words
A dual modulus dividing circuit for dividing first and second complementary clock signals from a clock signal source to generate first and second complementary output signals related to the first and second clock signals by a first modulus and a second modulus in response to the first and second complementary modulus control signals from a control signal source, said dividing circuit comprising: (a) first and second flip-flop circuits each including master and slave circuit means and each having first and second complementary flip-flop output signals for storing first and second complementary flip-flop input signals in response to the first and second complementary clock signals, the first and second output signals of the first flip-flop circuit being coupled to the first and second input signals of the second flip-flop circuit, respectively, the first and second output signals of the second flip-flop circuit coupled to the second and first input signals of the first flip-flop circuit, respectively, and said master and slave circuit means each having first and second complementary input signals and first and second complementary output signals, the first and second slave output signals providing the first and second flip-flop output signals, respectively, the first and second master input signals being coupled to the first and second flip-flop input signals, respectively, and the first and second slave input signals being coupled to the first and second master output signals; (b) said master circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first master output signals, respectively, and collector terminals providing said first and second master output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second master input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between a power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; (c) said slave circuit means comprising: (i) first and second switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said second and first slave output signals, respectively, and collector terminals providing said first and second slave output signals, respectively; (ii) third and fourth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second slave input signals, respectively, and collector terminals coupled to the collector terminals of the first and second switching transistors, respectively; (iii) fifth and sixth switching transistors each having emitter terminals intercoupled to one another, base terminals coupled to said first and second clock signals for said slave circuit means and to said second and first clock signals for said master circuit means, respectively, and collector terminals coupled to the intercoupled emitter terminals of the third and fourth switching transistors and the intercoupled emitter terminals of the first and second switching transistors, respectively; and (iv) first and second load means coupled between the power source and collector terminals of the first and second switching transistors, respectively, said first and second load means each being comprised of at least two series coupled, forward biased transistors interconnected to one another for continuously conducting current from said power source and each having an emitter terminal, a base terminal and a collector terminal connected to the base terminal; and (d) means coupled to the emitter terminals of the fifth and sixth switching transistors in the master and slave circuit means in the first and second flip-flop circuits for generating a predetermined bias current; and (e) a modulus control circuit coupled to a modulus control signal from a control signal source and being interposed between the intercoupled emitter terminals of the third and fourth switching transistors in the master circuit means in the first flip-flop circuit and the collector terminal of the fifth switching transistor in the master circuit means in the first flip-flop circuit, said modulus control circuit including seventh, eighth and ninth switching transistors each having base terminals, collector terminals and emitter terminals, the emitter terminals being intercoupled to one another, the base terminals of the seventh and eighth switching transistors being coupled to the first and second slave output signals in the first flip-flop circuit, the base terminal of the ninth switching transistor being coupled to the modulus control signal, the collector terminals of the seventh and ninth switching transistors being coupled to the intercoupled emitter terminals of the third and fourth switching transistors in the master circuit means in the first flip-flop circuit, the collector terminal of the eighth switching transistor being coupled to the collector terminal of the fourth switching transistor in the master circuit means in the first flip-flop circuit, and the emitter terminals of the seventh, eighth and ninth switching transistors being coupled to the collector terminal of the fifth switching transistor in the master circuit means in the first flip-flop circuit.
Claim 18
Dependent Claim
32 words
The dividing circuit according to claim 11, wherein siad bias current generating means includes means for varying the generated bias current in response to a control signal from a control signal source.
References Cited (Backward Citations)
US3622810A
Cited
US3886531A
Cited
US3917959A
Cited
US3942033A
Cited
US3978347A
Cited
US4095189A
Cited
US4165470A
Cited
US4118621A
Cited
US4122401A
Cited
US4253034A
Cited
US4258330A
Cited
US4353000A
Cited
US4215418A
Cited
US4316151A
Cited
US4325031A
Cited
US4308470A
Cited
US4353039A
Cited
SU940308A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-28 | 1989-10-28 | 1990-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-28 | 1993-10-28 | 1994-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-28 | 1997-10-28 | 1998-04-29 | $7700.00 | Window Closed / Lapsed |