IDT82V3255
WAN PLL
Pin Description
13
December 3, 2008
2
PIN DESCRIPTION
Table 1: Pin Description
Name
Pin No.
I/O
Type
Description 1
Global Control Signal
OSCI
6
I
CMOS
OSCI: Crystal Oscillator Master Clock
A nominal 12.8000 MHz clock provided by a crystal oscillator is input on this pin. It is the
master clock for the device.
FF_SRCSW
13
I
pull-down
CMOS
FF_SRCSW: External Fast Selection Enable
EXT_SW bit determines whether the External Fast Selection is enabled.
High: The default value of the EXT_SW bit (b4, 0BH) is ‘1’ (External Fast selection is
enabled);
Low: The default value of the EXT_SW bit (b4, 0BH) is ‘0’ (External Fast selection is dis-
abled).
enabled:
High: Pair IN1_CMOS / IN1_DIFF is selected.
Low: Pair IN2_CMOS / IN2_DIFF is selected.
After reset, the input on this pin takes no effect if the External Fast selection is disabled.
SONET/SDH
64
I
pull-down
CMOS
SONET/SDH: SONET / SDH Frequency Selection
During reset, this pin determines the default value of the IN_SONET_SDH bit (b2, 09H):
Low: The default value of the IN_SONET_SDH bit is ‘0’ (SDH).
After reset, the value on this pin takes no effect.
RST
48
I
pull-up
CMOS
RST: Reset
A low pulse of at least 50 s on this pin resets the device. After this pin is high, the device will
still be held in reset state for 500 ms (typical).
Frame Synchronization Input Signal
EX_SYNC1
28
I
pull-down
CMOS
EX_SYNC1: External Sync Input 1
A 2 kHz, 4 kHz or 8 kHz signal is input on this pin.
EX_SYNC2
33
I
pull-down
CMOS
EX_SYNC2: External Sync Input 2
A 2 kHz, 4 kHz or 8 kHz signal is input on this pin.
EX_SYNC3
35
I
pull-down
CMOS
EX_SYNC3: External Sync Input 3
A 2 kHz, 4 kHz or 8 kHz signal is input on this pin.
Input Clock
IN1_CMOS
29
I
pull-down
CMOS
IN1_CMOS: Input Clock 1
A 2 kHz, 4 kHz, N x 8 kHz 3, 1.544 MHz (SONET) / 2.048 MHz (SDH), 6.48 MHz, 19.44 MHz,
25.92 MHz, 38.88 MHz, 51.84 MHz, 77.76 MHz or 155.52 MHz clock is input on this pin.
IN2_CMOS
30
I
pull-down
CMOS
IN2_CMOS: Input Clock 2
A 2 kHz, 4 kHz, N x 8 kHz 3, 1.544 MHz (SONET) / 2.048 MHz (SDH), 6.48 MHz, 19.44 MHz,
25.92 MHz, 38.88 MHz, 51.84 MHz, 77.76 MHz or 155.52 MHz clock is input on this pin.
IN1_POS
IN1_NEG
23
24
I
PECL/LVDS
IN1_POS / IN1_NEG: Positive / Negative Input Clock 1
A 2 kHz, 4 kHz, N x 8 kHz 3, 1.544 MHz (SONET) / 2.048 MHz (SDH), 6.48 MHz, 19.44 MHz,
25.92 MHz, 38.88 MHz, 51.84 MHz, 77.76 MHz, 155.52 MHz, 311.04 MHz or 622.08 MHz
clock is differentially input on this pair of pins. Whether the clock signal is PECL or LVDS is
automatically detected.
IN2_POS
IN2_NEG
25
26
I
PECL/LVDS
IN2_POS / IN2_NEG: Positive / Negative Input Clock 2
A 2 kHz, 4 kHz, N x 8 kHz 3, 1.544 MHz (SONET) / 2.048 MHz (SDH), 6.48 MHz, 19.44 MHz,
25.92 MHz, 38.88 MHz, 51.84 MHz, 77.76 MHz, 155.52 MHz, 311.04 MHz or 622.08 MHz
clock is differentially input on this pair of pins. Whether the clock signal is PECL or LVDS is
automatically detected.