FN3192 Rev 0.00

Page 1 of 10

November 1994

FN3192

Rev 0.00

November 1994

CD14538BMS

CMOS Dual Precision Monostable Multivibrator

DATASHEET

Features

• High-Voltage Type (20V Rating)

• Retriggerable/Resettable Capability

• Trigger and Reset Propagation Delays Independent of

RX, CX

• Triggering From Leading or Trailing Edge

• Q and Q Buffered Outputs Available

• Separate Resets

• Wide Range of Output-Pulse Widths

• Schmitt-Trigger Input Allows Unlimited Rise and Fall

Times On +TR and -TR Inputs

• 100% Tested For Maximum Quiescent Current at 20V

• Maximum Input Current of 1

A at 18V Over Full Pack-

age-Temperature Range:

- 100nA at 18V and +25oC

• Noise Margin (Full Package-Temperature Range):

- 1V at VDD = 5V

- 2V at VDD = 10V

- 2.5V at VDD = 15V

• 5V, 10V and 15V Parametric Ratings

• Standardized Symmetrical Output Characteristics

• Meets All Requirements of JEDEC Tentative Standards

No. 13B, “Standard Specifications for Description of “B”

Series CMOS Device’s

Applications

• Pulse Delay and Timing

• Pulse Shaping

Functional Diagram

Description

CD14538BMS dual precision monostable multivibrator provides stable

retriggerable/resettable one-shot operation for any fixed-voltage timing

application.

An external resistor (RX) and an external capacitor (CX) control the tim-

ing and accuracy for the circuit. Adjustment of RX and CX provides a

wide range of output pulse widths from the Q and Q terminals. The

time delay from trigger input to output transition (trigger propagation

delay) and the time delay from reset input to output transition (reset

propagation delay) are independent of RX and CX. Precision control of

output pulse widths is achieved through linear CMOS techniques.

Leading-edge-triggering (+TR) and trailing-edge-triggering (-TR) inputs

are provided for triggering from either edge of an input pulse. An

unused +TR input should be tied to VSS. An unused -TR input should

be tied to VDD. A RESET (on low level) is provided for immediate ter-

mination of the output pulse or to prevent output pulses when power is

turned on. An unused RESET input should be tied to VDD. However, if

an entire section of the CD14538BMS is not used, its inputs must be

tied to either VDD or VSS. See Table 1.

In normal operation the circuit retriggers (extends the output pulse one

period) on the application of each new trigger pulse. For operation in

the non-retriggerable mode, Q is connected to -TR when leading-edge

triggering (+TR) is used or Q is connected to +TR when trailing-edge

triggering (-TR) is used. The time period (T) for this multivibrator can be

calculated by: T = RXCX.

The minimum value of external resistance, RX is 4K. The minimum

and maximum values of external capacitance, CX, are 0pF and 100F,

respectively.

The CD14538BMS is interchangeable with type MC14538 and is simi-

lar to and pin-compatible with the CD4098B* and CD4538B**.

* T = 0.5 RXCX for CX  1000pF.

*T = RXCX; CX min = 5000pF.

The CD14538BMS is supplied in these 16-lead outline packages:

Pinout

MONO1

MONO2

CX1

RX1

VDD

2

1RXCX(1)

6

7

10

9

4

5

3

12

11

13

15 14 RXCX(2)

VDD

CX2

RX2

Q1

Q1

Q2

Q2

+TR

-TR

RESET

+TR

-TR

RESET

VDD = 16

VSS = 8

Braze Seal DIP

H4X

Frit Seal DIP

H1L

Ceramic Flatpack H6W

CD14538BMS

TOP VIEW

14

15

16

9

13

12

11

10

1

2

3

4

5

7

6

8

CX1

RXCX (1)

RESET (1)

+TR (1)

-TR (1)

Q1

VSS

Q1

VDD

RXCX (2)

RESET (2)

+TR (2)

-TR (2)

Q2

Q2

CX2