sy89429a Micrel Semiconductor, sy89429a Datasheet - Page 3

• Manufacturer Part Number: sy89429a
• Description: Sy89429a Programmable Frequency Synthesizer 25mhz To 400mhz
• Manufacturer: Micrel Semiconductor

Micrel, Inc.
INPUTS
XTAL1, XTAL2
These pins form an oscillator when connected to an external
crystal. The crystal is series resonant. Alternatively, these pins
can be driven with 100K PECL level by an external source.
S_
This TTL pin loads the configuration latches with the contents
of the shift registers. The latches will be transparent when this
signal is HIGH; thus, the register data must be stable on the
HIGH-to-LOW transition of S_
S_
This TTL pin is the input to the serial configuration shift
registers.
S_
This TTL pin clocks the serial configuration shift registers. On
the rising edge of this signal, data from S_
P_
This TTL pin loads the configuration latches with the contents
of the parallel inputs. The latches will be transparent when
this signal is LOW; thus, the parallel data must be stable on
the LOW-to-HIGH transition of P_
M[8:0]
These TTL pins are used to configure the PLL loop divider.
They are sampled on the LOW-to-HIGH transition of P_
M[8] is the MSB, M[0] is the LSB. The binary count on the M
pins equates to the divide-by value for the PLL.
N[1:0]
These TTL pins are used to configure the output divider
modulus. They are sampled on the LOW-to-HIGH transition
of P_
PIN DESCRIPTIONS
LOAD
DATA
CLOCK
LOAD
LOAD
N[1:0]
0 0
0 1
1 0
1 1
.
LOAD
Output Division
LOAD
for proper operation.
16
2
4
8
for proper operation.
DATA
is sampled.
LOAD
.
3
OUTPUTS
FOUT, FOUT
These differential positive-referenced ECL signals (PECL)
are the output of the synthesizer.
TEST
The function of this TTL output is determined by the serial
configuration bits T[2:0].
POWER
V
This is the positive supply for the chip and is normally connected
to +5.0V.
V
This is the positive reference for the PECL outputs, FOUT and
FOUT. It is constrained to be less than or equal to
V
This is the positive supply for the PLL and should be as noise-
free as possible for low-jitter operation.
GND
These pins are the negative supply for the chip and are
normally all connected to ground.
OTHER
LOOP_FILTER
This is an analog I/O pin that provides the loop filter for the
PLL.
LOOP_REF
This is an analog I/O pin that provides a reference voltage
for the PLL.
CC1
CC_OUT
CC_QUIET
Precision Edge
SY89429A
VCC1
.
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