
ICS844002-01
FEMTOCLOCKS CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER
IDT / ICS LVDS FREQUENCY SYNTHESIZER
2
ICS844002AG-01 REV. A SEPTEMBER 28, 2007
Table 1. Pin Descriptions
NOTE: Pulldown refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Table 2. Pin Characteristics
Number
Name
Type
Description
1, 7
nc
Unused
No connect.
2, 20
VDDO
Power
Output supply pins.
3, 4
Q0, Q0
Output
Differential output pair. LVDS interface levels.
5
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 Qx to go high.
When logic LOW, the internal dividers and the outputs are enabled.
LVCMOS/LVTTL interface levels.
6
PLL_SEL
Input
Pulldown
Selects between the PLL and REF_CLK as input to the dividers. When LOW,
selects PLL (PLL Enable). When HIGH, deselects the reference clock (PLL
Bypass). LVCMOS/LVTTL interface levels.
8VDDA
Power
Analog supply pin.
9,
11
FSEL0,
F_SEL1
Input
Pulldown
Frequency select pins. LVCMOS/LVTTL interface levels.
10
VDD
Power
Core supply pins.
12,
13
XTAL_OUT,
XTAL_IN
Input
Parallel resonant crystal interface. XTAL_OUT is the output,
XTAL_IN is the input.
14
REF_CLK
Input
Pulldown
Non-inverting differential clock input.
15
XTAL_SEL
Input
Pulldown
Selects between crystal or REF_CLK inputs as the PLL Reference source.
Selects XTAL inputs when LOW. Selects REF_CLK when HIGH.
LVCMOS/LVTTL interface levels.
16
nc
Unused
No connect.
17
GND
Power
Power supply ground.
18, 19
Q1, Q1
Output
Differential output pair. LVDS interface levels.
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
CIN
Input Capacitance
4
pF
RPULLDOWN Input Pulldown Resistor
51
k