ICS843207-350
FEMTOCLOCKS™ CRYSTAL-TO-LVPECL 350MHZ FREQUENCY MARGINING SYNTHESIZER
PRELIMINARY
TABLE 2. PIN DESCRIPTIONS
Number
Number
Name
Name
Type
Type
Description
Description
1, 7, 12,
25, 30, 34
VCCO
Power
Output supply pins.
2, 3
4, 5
Q0, nQ0
Q1, nQ1
VEE
Ouput
Ouput
Power
Ouput
Ouput
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Negative supply pins.
6, 16, 31
8, 9
Q2, nQ2
Q3, nQ3
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
10, 11
MODE pin. LOW = default mode. HIGH = frequency margining mode.
See Table 4B. LVCMOS/LVTTL interface levels.
Sets the frequency to 5% in frequency margining mode.
See Table 1B. LVCMOS/LVTTL interface levels.
Active High Master Reset. When logic HIGH, the internal dividers are
reset causing the true outputs Qx to go LOW and inverted outputs
nQx to go HIGH. When logic LOW, the internal dividers and the
outputs are enabled. LVCMOS/LVTTL interface levels.
13
14
MODE
Margin
Input
Input
Pulldown
Pulldown
Pulldown
15
MR
Input
17
18
REF_CLK
Input
Input
Pulldown Reference input clock. LVCMOS/LVTTL interface levels.
Crystal select pin. Selects between the crystal and the reference
Pulldown
nXTAL_SEL
clock inputs. LVCMOS/LVTTL interface levels.
19,
20
XTAL_OUT,
XTAL_IN
Parallel resonant crystal interface. XTAL_OUT is the output,
XTAL_IN is the input.
Input
21, 35
VCC
Power
Core supply pins.
PLL select pin. When HIGH, PLL is bypassed and input is fed directly
Pulldown to the output dividers. When LOW, PLL is enabled.
LVCMOS/LVTTL interface levels.
22
nPLL_SEL
Input
Input
23, 24,
37, 38,
39, 40,
41, 42,
43, 44,
45, 46,
47, 48
SEL0, SEL1,
SEL2, SEL3,
SEL4, SEL5,
SEL6, SEL7,
SEL8, SEL9,
SEL10, SEL11,
SEL12, SEL13
Output divider select pins. See Table 1A.
Pullup
LVCMOS/LVTTL interface levels.
26, 27
28, 29
32, 33
36
Q4, nQ4
Q5, nQ5
Q6, nQ6
VCCA
Ouput
Ouput
Ouput
Power
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Differential output pair. LVPECL interface levels.
Analog supply pin.
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
TABLE 3. PIN CHARACTERISTICS
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum Units
CIN
Input Capacitance
4
pF
kΩ
kΩ
RPULLDOWN Input Pulldown Resistor
RPULLUP Input Pulldown Resistor
51
51
TABLE 4A. nXTAL_SEL CONTROL INPUT FUNCTION TABLE
Input
TABLE 4B. MODE CONTROL INPUT FUNCTION TABLE
Input
Condition
Q0:Q6, nQ0:nQ6
MODE
nXTAL_SEL
Selected Source
XTAL_IN, XTAL_OUT
REF_CLK
0
1
Default Mode
0
1
Frequency Margining Mode
IDT™ / ICS™ LVPECL FREQUENCY MARGINING SYNTHESIZER
3
ICS843207CY-350 REV. A DECEMBER 3, 2007