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CD4541B Datasheet, PDF (1/8 Pages) Texas Instruments – CMOS PROGRAMMABLE TIMER HIGH VOLTAGE TYPES(20V RATING) | |||
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Semiconductor
CD4541B
July 1998
CMOS Programmable Timer
High Voltage Types (20V Rating)
Features
⢠Low Symmetrical Output Resistance, Typically 100â¦
at VDD = 15V
⢠Built-In Low-Power RC Oscillator
⢠Oscillator Frequency Range . . . . . . . . . . DC to 100kHz
⢠External Clock (Applied to Pin 3) can be Used Instead
of Oscillator
⢠Operates as 2N Frequency Divider or as a Single-
Transition Timer
⢠Q/Q Select Provides Output Logic Level Flexibility
⢠AUTO or MASTER RESET Disables Oscillator During
Reset to Reduce Power Dissipation
⢠Operates With Very Slow Clock Rise and Fall Times
⢠Capable of Driving Six Low Power TTL Loads, Three
Low-Power Schottky Loads, or Six HTL Loads Over
the Rated Temperature Range
⢠Symmetrical Output Characteristics
⢠100% Tested for Quiescent Current at 20V
⢠5V, 10V, and 15V Parametric Ratings
⢠Meets All Requirements of JEDEC Standard No. 13B,
âStandard Speciï¬cations for Description of âBâ Series
CMOS Devicesâ
Ordering Information
PART NUMBER
CD4541BF
CD4541BE
CD4541BH
CD4541BM
TEMP.
RANGE (oC)
PACKAGE
-55 to 125 14 Ld CERDIP
-55 to 125 14 Ld PDIP
-55 to 125 Chip
-55 to 125 14 Ld SOIC
PKG.
NO.
F14.3
E14.3
-
M14.15
Description
CD4541B programmable timer consists of a 16-stage binary
counter, an oscillator that is controlled by external R-C compo-
nents (2 resistors and a capacitor), an automatic power-on
reset circuit, and output control logic. The counter increments
on positive-edge clock transitions and can also be reset via the
MASTER RESET input.
The output from this timer is the Q or Q output from the 8th,
10th, 13th, or 16th counter stage. The desired stage is chosen
using time-select inputs A and B (see Frequency Select Table).
The output is available in either of two modes selectable via the
MODE input, pin 10 (see Truth Table). When this MODE input is
a logic â1â, the output will be a continuous square wave having
a frequency equal to the oscillator frequency divided by 2N.
With the MODE input set to logic â0â and after a MASTER
RESET is initiated, the output (assuming Q output has been
selected) changes from a low to a high state after 2N-1 counts
and remains in that state until another MASTER RESET pulse
is applied or the MODE input is set to a logic â1â.
Timing is initialized by setting the AUTO RESET input (pin 5) to
logic â0â and turning power on. If pin 5 is set to logic â1â, the
AUTO RESET circuit is disabled and counting will not start until
after a positive MASTER RESET pulse is applied and returns
to a low level. The AUTO RESET consumes an appreciable
amount of power and should not be used if low-power operation
is desired. For reliable automatic power-on reset, VDD should
be greater than 5V.
The RC oscillator, shown in Figure 2, oscillates with a
frequency determined by the RC network and is calculated
using:
f = -2---.--3-----R-----T-1---C----C-----T---C--
Where f is between 1kHz
and 100kHz
and RS ⥠10k⦠and â 2RTC
Pinout
CD4541B (CERDIP, PDIP, SOIC)
TOP VIEW
RTC 1
CTC 2
RS 3
NC 4
AUTO RESET 5
MASTER RESET 6
VSS 7
14 VDD
13 B
12 A
11 NC
10 MODE
9 Q/Q SELECT
8 OUTPUT
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright © Harris Corporation 1998
1
File Number 1378.1
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