
ICS844004AKI-104 REVISION A DECEMBER 15, 2010
2
2010 Integrated Device Technology, Inc.
ICS844004I-104 Data Sheet
FEMTOCLOCK CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER
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, 2
Q0, nQ0
Output
Differential output pair. LVDS 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.
LVCMOS/LVTTL interface levels.
4
nPLL_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.
5, 6, 7, 8, 15,
16, 20, 21,
28, 29
nc
Unused
No connect.
9VDDA
Power
Analog supply pin.
10,
12
F_SEL0,
F_SEL1
Input
Pulldown
Frequency select pin. LVCMOS/LVTTL interface levels.
11
VDD
Power
Core supply pin.
13,
14
XTAL_OUT
XTAL_IN
Input
Crystal oscillator interface. XTAL_IN is the input, XTAL_OUT is the output.
17, 22
GND
Power
Power supply ground.
18
REF_CLK
Input
Pulldown
Single-ended reference clock input. LVCMOS/LVTTL interface levels.
19
nXTAL_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.
23, 24
nQ3, Q3
Output
Differential output pair. LVDS interface levels.
25, 32
VDDO
Power
Output supply pins.
26, 27
Q2, nQ2
Output
Differential output pair. LVDS interface levels.
30, 31
nQ1, 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