ICS841664AGI REVISION A JULY 15, 2013 2 ©2013 Integrated Device Technology, Inc.
ICS841664I Data Sheet FEMTOCLOCK
®
CRYSTAL-TO-HCSL CLOCK GENERATOR
Pin Description and Pin Characteristic Tables
Table 1. Pin Descriptions
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Table 2. Pin Characteristics
Number Name Type Description
1, 18 V
DD
Power Core supply pins.
2 REF_OUT Output LVCMOS/LVTTL reference frequency clock output.
3, 7, 15, 22 GND Power Power supply ground.
4, 5,
8, 9
QA0, nQA0
QA1, nQA1
Output Differential Bank A output pairs. HCSL interface levels.
6V
DDOA
Power Output supply pin for Bank A outputs.
10 nREF_OE Input Pullup
Active low REF_OUT enable/disable. See Table 3E.
LVCMOS/LVTTL interface levels.
11 BYPASS Input Pulldown Selects PLL/PLL bypass mode. See Table 3C. LVCMOS/LVTTL interface levels.
12 REF_IN Input Pulldown LVCMOS/LVTTL reference clock input.
13 REF_SEL Input Pulldown
Reference select, Selects the input reference source. See Table 3B.
LVCMOS/LVTTL interface levels
14 V
DDA
Power Analog supply pin.
16,
17
XTAL_OUT,
XTAL_IN
Input
Parallel resonant crystal interface. XTAL_OUT is the output,
XTAL_IN is the input.
19 MR/nOE Input Pulldown
Active HIGH master reset. Active LOW output enable. When logic HIGH, the
internal dividers are reset and the outputs are in high impedance. When logic
LOW, the internal dividers and the outputs are enabled. See Table 3D.
LVCMOS/LVTTL interface levels.
20, 21,
24, 25
nQB1, QB1
nQB0, QB0
Output Differential Bank B output pairs. HCSL interface levels.
23 V
DDOB
Power Output supply pin for Bank B outputs.
26,
27
FSEL1,
FSEL0
Input Pulldown Output frequency select pins. LVCMOS/LVTTL interface levels.
28 IREF Output
HCSL current reference resistor output. A fixed precision resistor (475) form this
pin to ground provides a reference current used for differential current-mode
QX[0:1], nQX[0:1] clock outputs.
Symbol Parameter Test Conditions Minimum Typical Maximum Units
C
IN
Input Capacitance 4pF
C
PD
Power Dissipation Capacitance V
DD
= 3.465V 4 pF
R
PULLUP
Input Pullup Resistor 51 k
R
PULLDOWN
Input Pulldown Resistor 51 k
R
OUT
Output Impedance REF_OUT V
DD
= 3.465V 20
