器件名称: 74HC4538
功能描述: Dual Precision Retriggerable/Resettable Monostable Multivibrators
文件大小: 81.46KB 共16页
简 介:HD74HC4538
Dual Precision Retriggerable/Resettable Monostable Multivibrators
Description
Each multivibrator features both a negative, A, and a positive, B, transition triggered input, either of which can be used as an inhibit input. Also included is a clear input that when taken low resets the one short. The HD74HC4538 is retriggerable. That is, it may be triggered repeatedly while their outputs are generating a pulse and the pulse will be extended. Pulse width stability over a wide range of temperature. The output pulse equation is simply: tw = 0.7 (R) (C).
Features
High Speed Operation: tpd (A or B to Y) = 22 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Operating Voltage: VCC = 2 to 6 V Low Input Current: 1 A max Low Quiescent Supply Current
Function Table
Inputs CD L H H H H X : Irrelevant H L A X L H Not triggered Not triggered B X Outputs Q L Q H
HD74HC4538
Pin Arrangement
T1A T2A CDA AA BA QA QA GND
1 2 3 4 5 6 7 8 (Top view)
T1 T2 T1
16 VCC 15 T1B 14 T2B 13 CDB 12 AB 11 BB 10 QB 9 QB
CD
T2
A
CD
B
A
Q
B
Q
Q
Q
2
HD74HC4538
Block Diagram
CX RX VCC T1A T2A
QA AA BA QA CDA CX RX VCC T1B T2B
QB AB BB QB CDB RX and CX are external components
3
HD74HC4538
Absolute Maximum Ratings
Item Supply voltage range Input voltage Output voltage DC input diode current DC input diode current pin 2, 14 DC output diode current DC current drain per pin DC current drain per VCC, GND Power dissipation per package Storage temperature Symb……
