FEMTOCLOCKS™ CRYSTAL-TOLVCMOS/
LVTTL FREQUENCY SYNTHESIZER
840002 DATA SHEET
2 REVISION C 11/10/14
TABLE 1. PIN DESCRIPTIONS
TABLE 2. PIN CHARACTERISTICS
TABLE 3. FREQUENCY SELECT FUNCTION TABLE
Number Name Type Description
1 F_SEL0 Input Pullup Frequency select pin. LVCMOS/LVTTL interface levels.
2 nXTAL_SEL Input Pulldown
Selects between the crystal or TEST_CLK inputs as the PLL reference
source. When HIGH, selects TEST_CLK. When LOW, selects XTAL
inputs. LVCMOS/LVTTL interface levels.
3 TEST_CLK Input Pulldown Single-ended LVCMOS/LVTTL clock input.
4 OE Input Pullup
Output enable pin. When HIGH, the outputs are active. When LOW, the
outputs are in a high impedance state. LVCMOS/LVTTL interface levels.
5 MR Input Pulldown
Active HIGH Master Reset. When logic HIGH, the internal dividers are
reset causing active outputs to go low. When logic LOW, the internal
dividers and the outputs are enabled. LVCMOS/LVTTL interface levels.
6 nPLL_SEL Input Pulldown
PLL Bypass. When LOW, the output is driven from the VCO output.
When HIGH, the PLL is bypassed and the output frequency = reference
clock frequency/n output divider.
LVCMOS/LVTTL interface levels.
7V
DDA
Power Analog supply pin.
8V
DD
Power Core supply pin.
9,
10
XTAL_OUT,
XTAL_IN
Input Crystal oscillator interface.
11 V
DDO
Power Output supply pin.
12, 13 Q1, Q0 Output Single-ended clock outputs. LVCMOS/LVTTL interface levels.
14, 15 GND Power Power supply ground.
16 F_SEL1 Input Pullup Frequency select pin. LVCMOS/LVTTL interface levels.
NOTE: Pullup and Pulldown refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
Input Frequency
(MHz)
Inputs
Output Frequency
(MHz)
F_SEL1 F_SEL0 M Divider Value N Divider Value M/N Divider Value
26.5625 0 0 24 3 8 212.5
26.5625 0 1 24 4 6 159.375
26.5625 1 0 24 6 4 106.25
26.5625 1 1 24 12 2 53.125
26.04166 0 1 24 4 6 156.25
Symbol Parameter Test Conditions Minimum Typical Maximum Units
C
IN
Input Capacitance 4 pF
C
PD
Power Dissipation Capacitance 8 pF
R
PULLUP
Input Pullup Resistor 51 kΩ
R
PULLDOWN
Input Pulldown Resistor 51 kΩ
R
OUT
Output Impedance
3.3V±5% 14 17 21 Ω
2.5V±5% 16 21 25 Ω
