CDP68HC68W1
CMOS Serial Digital Pulse Width Modulator
March 1998
Features
Description
• Programmable Frequency and Duty Cycle Output
The CDP68HC68W1 modulates a clock input to supply a
variable frequency and duty-cycle output signal. Three 8-bit
registers (pulse width, frequency and control) are accessed
serially after power is applied to initialize device operation.
The value in the pulse width register selects the high
duration of the output period. The frequency register byte
divides the clock input frequency and determines the overall
output clock period. The input clock can be further divided by
two or a low power mode may be selected by the lower two
bits in the control register. A comparator circuit allows
threshold control by setting the output low if the input at the
• Serial Bus Input; Compatible with Motorola/Intersil
SPI Bus, Simple Shift-Register Type Interface
• 8 Lead PDIP Package
• Schmitt Trigger Clock Input
o
o
• 4V to 6V Operation, -40 C to 85 C Temperature Range
• 8MHz Clock Input Frequency
Pinout
V pin rises above 0.75V. The CDP68HC68W1 is supplied in
an 8 lead PDIP package (E suffix).
T
CDP68HC68W1
(PDIP)
TOP VIEW
Ordering Information
CLK
CS
1
2
3
4
8
7
6
5
V
DD
TEMP. RANGE
PKG.
NO.
o
PWM
SCK
PART NUMBER
( C)
PACKAGE
V
T
CDP68HC68W1E
-40 to 85
8 Ld PDIP
E8.3
V
DATA
SS
Block Diagram
PWM
INPUT CLK
MODULATOR
LOGIC
CLK
8 - STAGE RIPPLE
COUNTER
8 - STAGE RIPPLE
COUNTER
RESET
LOAD
PULSE - WIDTH
DATA REGISTER
FREQUENCY
DATA REGISTER
LOAD
DATA
8 - STAGE SHIFT
REGISTER
8 - STAGE SHIFT
REGISTER
CONTROL REGISTER
2 - STAGE SHIFT
LOAD
V
T
V
T
COMPARATOR
SCK
8
16
24
5 - STAGE 24 - STATE
COMPARATOR
CS
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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File Number 1919.3
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