ICS8440258-46 Datasheet, PDF (2/16 Pages) Integrated Device Technology – FEMTOCLOCK™ CRYSTAL/LVCMOS-TOLVDS/LVCMOS FREQUENCY SYNTHESIZER

ICS8440258-46
FEMTOCLOCK™ CRYSTAL/LVCMOS-TO-LVDS/ LVCMOS FREQUENCY SYNTHESIZER
PRELIMINARY
TABLE 1. PIN DESCRIPTIONS
Number
Name
Type
Description
1, 2
Q0, nQ0
Output
Differential clock outputs. LVDS interface levels.
3, 12, 16,
17, 21
GND
Power
Power supply ground.
4, 5
Q1, nQ1
Output
Differential clock outputs. LVDS interface levels.
6, 11, 27
7, 8
V_DD
Q2, nQ2
Power
Output
Core supply pin.
Differential clock outputs. LVDS interface levels.
9, 10
13, 15,
18, 20
14
19
22, 23, 24
Q3, nQ3
Q4, Q5,
Q6, Q7
V_DDO1
V
DDO2
nc
Output
Output
Power
Power
Unused
Differential clock outputs. LVDS interface levels.
Single-ended clock outputs. LVCMOS/LVTTL interface levels.
Power output supply pin for Q4 and Q5 LVCMOS outputs.
Power output supply pin for Q6 and Q7 LVCMOS outputs.
No connect.
25
V_DDA
Power
Analog supply pin.
PLL Bypass. When LOW, the output is driven from the VCO output.
26
nPLL_SEL
Input
Pulldown
When HIGH, the PLL is bypassed and the output frequency =
reference clock frequency/N output divider.
LVCMOS/LVTTL interface levels.
Active HIGH Master Reset. When logic HIGH, the internal dividers are
28
MR
Input Pulldown reset causing the outputs to go low. When logic LOW, the internal
dividers and the outputs are enabled. LVCMOS/LVTTL interface levels.
29
REF_CLK
Input Pulldown Single-ended LVCMOS/LVTTL reference clock input.
Selects between the crystal or REF_CLK inputs as the PLL reference
30
nXTAL_SEL Input Pulldown source. When HIGH, selects REF_CLK. When LOW, selects XTAL
inputs. LVCMOS/LVTTL interface levels.
31,
32
XTAL_OUT,
XTAL_IN
Input
Crystal oscillator interface. XTAL_OUT is the output.
XTAL_IN is the input.
NOTE: Pulldown refers to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 2. PIN CHARACTERISTICS
Symbol
C_IN
C_PD
R_PULLDOWN
R_OUT
Parameter
Input Capacitance
Power Dissipation Capacitance
Input Pulldown Resistor
Output Impedance
Test Conditions
Minimum
Typical
4
8
51
22
Maximum
Units
pF
pF
kΩ
Ω
IDT^™ / ICS^™ LVDS/LVCMOS FREQUENCY SYNTHESIZER
2
ICS8440258AK-46 REV B JANUARY 15, 2008