CD14538BMS
CMOS Dual Precision
Monostable Multivibrator
November 1994
Features
Description
• High-Voltage Type (20V Rating)
CD14538BMS dual precision monostable multivibrator provides stable retrigger-
able/resettable one-shot operation for any fixed-voltage timing application.
• Retriggerable/Resettable Capability
• Trigger and Reset Propagation Delays Inde-
pendent of RX, CX
An external resistor (RX) and an external capacitor (CX) control the timing and
accuracy for the circuit. Adjustment of RX and CX provides a wide range of out-
put 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. Pre-
cision control of output pulse widths is achieved through linear CMOS tech-
niques.
• 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
Leading-edge-triggering (+TR) and trailing-edge-triggering (-TR) inputs are pro-
vided 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 termination of the output pulse or to pre-
vent 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.
• 100% Tested For Maximum Quiescent Cur-
rent at 20V
• Maximum Input Current of 1µA at 18V Over
Full Package-Temperature Range:
- 100nA at 18V and +25oC
• Noise Margin (Full Package-Temperature
Range):
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-retrigger-
able 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.
- 1V at VDD = 5V
- 2V at VDD = 10V
- 2.5V at VDD = 15V
The minimum value of external resistance, RX is 4KΩ. The minimum and maxi-
mum values of external capacitance, CX, are 0pF and 100µF, respectively.
• 5V, 10V and 15V Parametric Ratings
• Standardized Symmetrical Output Charac-
teristics
The CD14538BMS is interchangeable with type MC14538 and is similar to and
pin-compatible with the CD4098B* and CD4538B**.
• Meets All Requirements of JEDEC Tentative
Standards No. 13B, “Standard Specifica-
tions for Description of “B” Series CMOS
Device’s
* T = 0.5 R C for C ≥ 1000pF.
X
X
X
* T = R C ; C min = 5000pF.
X
X
X
The CD14538BMS is supplied in these 16-lead outline packages:
Applications
• Pulse Delay and Timing
Braze Seal DIP
Frit Seal DIP
H4X
H1L
• Pulse Shaping
Ceramic Flatpack H6W
Pinout
Functional Diagram
CX1
2
RX1
CD14538BMS
TOP VIEW
VDD
1
RXCX(1)
6
CX1
RXCX (1)
RESET (1)
+TR (1)
-TR (1)
Q1
1
2
3
4
5
6
7
8
16 VDD
+TR
-TR
4
5
3
Q1
Q1
15 CX2
MONO1
MONO2
14 RXCX (2)
13 RESET (2)
12 +TR (2)
11 -TR (2)
10 Q2
RESET
7
+TR 12
-TR 11
10 Q2
RESET 13
9
Q2
Q1
9
Q2
VSS
15 14 RXCX(2)
CX2 RX2
VDD = 16
VSS = 8
VDD
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
File Number 3192
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