1I CD20 51
fax id: 3512
ICD2051
Dual Programmable Clock Generator
Features
鈥?Two independent clock outputs ranging from 320 kHz
to 100 MHz
鈥?Individually programmable PLLs use 22-bit serial word
鈥?Low-skew
梅1,梅2,
and
梅4
CLKA outputs
鈥?Phase-locked loop oscillator input derived from exter-
nal low-frequency reference clock (1 MHz - 25 MHz) or
external crystal (2 MHz - 24 MHz)
鈥?Sophisticated internal loop-filter requires no external
components or manufacturing tweaks as commonly re-
quired with external filters
鈥?Three-state control disables outputs for test purposes
(optional)
鈥?5V operation
鈥?Low-power, high-speed CMOS technology
鈥?Available in 16-pin SOIC package
Functional Description
The ICD2051 Programmable Clock Generator offers two fully
user-programmable phase-locked loops in a single package.
The outputs may be changed 鈥渙n the fly鈥?to any desired fre-
quency value between 320 kHz and 100 MHz. The ICD2051
is ideally suited for any design where one or more multiple or
varying frequencies are required, thus replacing more expen-
sive metal can oscillators.
The capability to dynamically change the output frequency
adds a whole new degree of freedom for the electrical engi-
neer. Some examples of the uses for this device include: lap-
top computers, in which slowing the speed of operation can
mean less power consumption or speeding it up can mean
faster operation; graphics board dot clocks to allow dynamic
synchronization with different brands of monitors or display
formats; and on-board test strategies where the ability to
skew a system鈥檚 desired frequency (for example
鹵10%)
al-
lows worst case evaluations.
Logic Block Diagram
f
(REF)
XTALIN
梅
q
7
7
3
Phase
Detector
Charge
Pump
VCO
XTALOUT
Internal Loop Filter
梅2p
post-VCO divider select
碌Code
Decode
VCO range select
4
Phase-Locked Loop Oscillator Section A
MUX
MUXREFA
梅2
梅4
CLKA
CLKA/2
CLKA/4
XBUF
PLL
SectionB
SCLKA
DATA
GND V
DD
SCLKB
MUXREFB
22
Serial
Rcvr A
MUX
CLKB
22
Serial
Rcvr B
OEA
OEB
ICD2051鈥?
Cypress Semiconductor Corporation
鈥?/div>
3901 North First Street
鈥?/div>
San Jose
鈥?/div>
CA 95134 鈥?/div>
408-943-2600
January 1995 鈥?Revised April 1995
1
2
3
4
5
6
7
8
