ICS843003
FEMTOCLOCKS CRYSTAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
IDT / ICS LVPECL FREQUENCY SYNTHESIZER
2
ICS843003AG REV. A FEBRUARY 19, 2008
Table 1. Pin Descriptions
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Number
Name
Type
Description
1
DIV_SELB0
Input
Pulldown
Division select pin for Bank B. Default = Low. LVCMOS/LVTTL interface levels.
2
VCO_SEL
Input
Pullup
VCO select pin. When Low, the PLL is bypassed and the crystal reference or
TEST_CLK (depending on XTAL_SEL setting) are passed directly to the output
dividers. Has an internal pullup resistor so the PLL is not bypassed by default.
LVCMOS/LVTTL interface levels.
3
MR
Input
Pulldown
Active HIGH Master Reset. When logic HIGH, the internal dividers are reset
causing the true outputs Qx to go low and the inverted outputs nQx to go high.
When logic LOW, the internal dividers and the outputs are enabled. Has an internal
pulldown resistor so the power-up default state of outputs and dividers are enabled.
LVCMOS/LVTTL interface levels.
4VCCO_A
Power
Output supply pin for Bank A outputs.
5, 6
QA0, nQA0
Output
Differential output pair. LVPECL interface levels.
7
OEB
Input
Pullup
Output enable Bank B. Active High output enable. When logic HIGH, the output pair
on Bank B is enabled. When logic LOW, the output pair drives differential Low
(QB0 = Low, nQB0 = High). Has an internal pullup resistor so the default power-up
state of outputs are enabled. LVCMOS/LVTTL interface levels.
8
OEA
Input
Pullup
Output enable Bank A. Active High output enable. When logic HIGH, the 2 output
pairs on Bank A are enabled. When logic LOW, the output pair drives differential
Low (QA0 = Low, nQA0 = High). Has an internal pullup resistor so the default
power-up state of outputs are enabled. LVCMOS/LVTTL interface levels.
9
FB_DIV
Input
Pulldown
Feedback divide select. When Low (default), the feedback divider is set for ÷20.
When HIGH, the feedback divider is set for ÷24. LVCMOS/LVTTL interface levels.
10
VCCA
Power
Analog supply pin.
11
VCC
Power
Core supply pin.
12
DIV_SELA0
Input
Pullup
Division select pin for Bank A. Default = HIGH. LVCMOS/LVTTL interface levels.
13
DIV_SELA1
Input
Pulldown
Division select pin for Bank A. Default = Low. LVCMOS/LVTTL interface levels.
14
VEE
Power
Negative supply pin.
15,
16
XTAL_OUT,
XTAL_IN
Input
Parallel resonant crystal interface. XTAL_OUT is the output, XTAL_IN is the input.
XTAL_IN is also the overdrive pin if you want to overdrive the crystal circuit with a
single-ended reference clock.
17
TEST_CLK
Input
Pulldown
Single-ended reference clock input. Has an internal pulldown resistor to pull to low
state by default. Can leave floating if using the crystal interface.
LVCMOS/LVTTL interface levels.
18
XTAL_SEL
Input
Pullup
Crystal select pin. Selects between the single-ended TEST_CLK or crystal
interface. Has an internal pullup resistor so the crystal interface is selected by
default. LVCMOS/LVTTL interface levels.
19, 20
nQB1, QB1
Output
Differential output pair. LVPECL interface levels.
21, 22
nQB01, QB0
Output
Differential output pair. LVPECL interface levels.
23
VCCO_B
Power
Output supply pin for Bank B outputs.
24
DIV_SELB1
Input
Pullup
Division select pin for Bank B. Default = High. LVCMOS/LVTTL interface levels.