Rochester Sensors 54LS691FK/B

View All Display Drivers by Rochester Sensors

Part Number:
54LS691FK/B
Manufacturer:
Rochester Sensors
Category:
Display Drivers
RoHs:
Non-RoHS Compliant
Datasheet:
Description:
54LS691FK/B
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Specifications

Type

Paramete

Type

Paramete

Package / Case

Reset

Timing

Trigger Type

Grade

Direction

Number of Bits per Element

Number of Elements

Qualification

Supplier Device Package

Voltage - Supply

Mounting Type

Operating Temperature

Count Rate

Logic Type

Overview

54LS691FK/B (54LS691FKB‑ROCV) – Synchronous 4‑Bit Binary Counter with Output Register & 3‑State Outputs (Full Summary)

1. Basic Identification

Manufacturer: Rochester Electronics (built to original TI/OCM specs)
Part Number: 54LS691FK / 54LS691FKB‑ROCV
Family: SN54LS691 (military grade)
Type: 4‑bit synchronous binary counter + output register + multiplexed 3‑state outputs
Package: FK package (20‑pin ceramic flat pack); military temperature range
Key Function: Direct (asynchronous) clear; counter + register; multiplexed bus‑drive outputs
Quality: ISO 9001, AS9120, QML MIL‑PRF‑38535 Class Q (Military), Class V (Space)

2. Key Features

4‑bit synchronous binary counter (counts 0–15)
Separate 4‑bit D‑type output register
Multiplexer selects counter or register data to 3‑state outputs
3‑state outputs directly drive bus lines (12 mA sink / 1 mA source for 54LS)
Asynchronous (direct) master clear (CCLR)
Separate clocks for counter (CCK) and register (RCK)
Synchronous parallel load capability
Carry lookahead for easy cascading (RCO)
Low‑power Schottky TTL (LS) technology

3. Pinout (20‑Pin FK Package, Top View)

表格

Pin	Symbol	Function	Pin	Symbol	Function
1	CCLR	Counter clear (active low, async)	11	R/C	Register/counter select
2	CCK	Counter clock (rising edge)	12	G	Output enable (active low)
3	A	Data input A	13	LOAD	Parallel load (active low)
4	B	Data input B	14	ENT	Count enable T
5	C	Data input C	15	QD	Output D
6	D	Data input D	16	QC	Output C
7	ENP	Count enable P	17	QB	Output B
8	RCLR	Register clear (active low)	18	QA	Output A
9	RCK	Register clock (rising edge)	19	RCO	Ripple carry output
10	GND	Ground	20	VCC	Supply voltage

4. Absolute Maximum Ratings

表格

Parameter	Value	Unit
Supply voltage (VCC)	7	V
Input voltage	7	V
Off‑state output voltage	5.5	V
Operating free‑air temperature (TA)	−55 to +125	°C
Storage temperature	−65 to +150	°C

5. Recommended Operating Conditions (54LS)

表格

Parameter	Min	Nom	Max	Unit
VCC supply voltage	4.5	5	5.5	V
High‑level input voltage (VIH)	2	—	—	V
Low‑level input voltage (VIL)	—	—	0.7	V
High‑level output current (IOH)	—	—	−1	mA
Low‑level output current (IOL)	—	—	12	mA
Clock frequency (CCK, RCK)	0	—	20	MHz
Pulse duration (clock high/low)	25	—	—	ns
Setup time (data, enable, load)	30	—	—	ns
Hold time	0	—	—	ns

6. Functional Description

Counter: 4‑bit synchronous binary up counter; counts on CCK rising edge when ENP=ENT=1, LOAD=1, CCLR=1
Register: 4‑bit D‑type register; captures counter outputs on RCK rising edge
Multiplexer: R/C = LOW → counter to outputs; R/C = HIGH → register to outputs
3‑state outputs: Enabled when G = LOW; high‑Z when G = HIGH
Clear: CCLR (async) resets counter; RCLR (async) resets register
Load: LOAD = LOW loads A–D into counter on CCK rising edge
Cascade: RCO = HIGH when counter = 15 and ENT = 1

7. DC Electrical Characteristics (TA = −55 to 125 °C, VCC = 4.5–5.5 V)

表格

Parameter	Conditions	Min	Max	Unit
Output HIGH voltage (VOH)	IOH = −1 mA	2.4	—	V
Output LOW voltage (VOL)	IOL = 12 mA	—	0.4	V
Input HIGH current (IIH)	VIN = 2.7 V	—	20	μA
Input LOW current (IIL)	VIN = 0.4 V	—	−0.4	mA
Quiescent supply current (ICC)	—	—	70	mA

8. Switching Characteristics (VCC = 5 V, TA = 25 °C)

表格

Parameter	Conditions	Typ	Max	Unit
Propagation delay CCK → RCO	RL = 2 kΩ, CL = 15 pF	13	40	ns
Propagation delay CCK → Q	RL = 667 Ω, CL = 45 pF	17	30	ns
Output enable time (tPZH, tPZL)	—	17	30	ns
Output disable time (tPHZ, tPLZ)	—	17	30	ns
Maximum clock frequency	—	—	20	MHz

9. Ordering & Marking

Part Numbers: 54LS691FK, 54LS691FKB‑ROCV
Package: 20‑pin ceramic flat pack (FK)
Marking: Includes part number, date code, lot code, assembly site
Availability: Military and high‑reliability applications

10. Reliability & Compliance

Tested per original OCM test programs
Qualified for military and space environments
ESD‑sensitive; follow proper handling procedures
Specifications match or exceed original manufacturer datasheet

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