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US5248905A Expired / Lapsed US ⏱️ 0.0 years remaining

High speed, master/slave latch transceiver having a directly-driven slave stage

Assignee: National Semiconductor Corp
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Filing: 1990-12-28
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Granted: 1993-09-28
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Expires: 2010-12-28
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Abstract

Abstract A multi-bit latch transceiver is designed to meet the IEEE 1194.1 standard for backplane transceiver logic as specified in the IEEE 896.2 Futurebus+ specification. The latch transceiver features support for live insertion, low skew, controlled rise/fall time (2ns-5ns) and glitch free power-up/down protection. The transceiver utilizes on-chip latches and a built-in bandgap reference that provides very accurate thresholds. Unique slave stage logic in the transceiver's driver stage provides preset input conditions to the slave latch such that data is instantly clocked to the driver output when the driver is enabled, thus reducing propagation delay.

Inventors

  • 👤 James R. Kuo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 09:12
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/38; G06F13/40; G06F13/4063; G06F13/4068; G06F13/4072; G06F13/4077; H; H03; H03K; H03K3/00; H03K3/02; H03K3/027; H03K3/037; H03K3/0372

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 249 words
A latch transceiver comprising: a clock generator that responds to an input clock signal by providing both a first clock signal and a second clock signal that has an active state and an inactive state; a master latch stage that responds to a data input signal having first and second logic states and to the first clock signal by providing a master latch output signal; a slave latch stage that includes (i) NAND gate invertor logic coupled to receive the master latch output signal and responsive to the second clock signal in the active state for providing the master latch output signal to a slave stage logic output node if the data input is the first logic state; and (ii) AND gate non-invertor logic coupled to receive the master latch output signal and responsive to the second clock signal in the active state for providing the master latch output signal to the slave stage logic output node if the data input is the second logic state, and wherein both the NAND gate invertor logic and the AND gate non-invertor logic respond to the second clock signal in the inactive state by providing a high-impedance output signal at the slave stage logic output node; and a driver stage coupled to the slave stage logic output node and that responds to the master latch output signal at the slave stage logic output node when the second clock signal is in the active state by providing a corresponding latch transceiver output signal.
Claim 2
Dependent Claim 249 words
A latch transceiver comprising: a clock generator that responds to an input clock signal by providing both a first clock signal and a second clock signal that has an active state and an inactive state; a master latch stage that responds to a data input signal having first and second logic states and to the first clock signal by providing a master latch output signal; a slave latch stage that includes (i) NAND gate invertor logic coupled to receive the master latch output signal and responsive to the second clock signal in the active state for providing the master latch output signal to a slave stage logic output node if the data input is the first logic state; and (ii) AND gate non-invertor logic coupled to receive the master latch output signal and responsive to the second clock signal in the active state for providing the master latch output signal to the slave stage logic output node if the data input is the second logic state, and wherein both the NAND gate invertor logic and the AND gate non-invertor logic respond to the second clock signal in the inactive state by providing a high-impedance output signal at the slave stage logic output node; and a driver stage coupled to the slave stage logic output node and that responds to the master latch output signal at the slave stage logic output node when the second clock signal is in the active state by providing a corresponding latch transceiver output signal.
Claim 3
Dependent Claim 45 words
A latch transceiver as in claim 1 and wherein the clock generator includes a npn emitter follower transistor having its collector coupled to a supply voltage, its emitter coupled to provide the second clock signal and its base coupled to receive the input clock signal.

References Cited (Backward Citations)

US3603815A Cited
US4258273A Cited
JPS59190711A Cited
EP0162718A2 Cited
EP0225075A2 Cited
JPS6458817A Cited
US4900949A Cited
US5017808A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-09-27 1997-03-29 1997-09-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-09-27 2001-03-29 2001-09-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-09-27 2005-03-29 2005-09-28 $7700.00 Window Closed / Lapsed

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