SONET/SDH CLOCK RECOVERY UNIT
Table 2. Pin Assignment and Descriptions
Pin Name
Level
Diff.
PECL
TTL
I/O
Pin#
Description
S3040B
SERDATIP/N
I
5,6
Serial Data In. (Internal Termination.) Clock is recovered from the
transitions on these inputs.
Bypass Enable. Active High. Used during production test to
bypass the VCO in the PLL. Tie to ground for normal operation.
Signal Detect. Active Low. A single-ended 10K PECL input to be
driven by the external optical receiver module to indicate a loss of
received optical power. When SDN is inactive, the data on the
Serial Data In (SERDATIP/N) pins will be internally forced to a
constant zero, and the PLL will be forced to lock to the REFCLK
inputs. When SDN is active, data on the SERDATIP/N pins will be
processed normally.
Reference Clock. 155.52 MHz input used to establish the initial
operating frequency of the clock recovery PLL and also used as
a standby clock in the absence of data, during reset or when SDN
is inactive.
Loop Filter Capacitor. The loop filter capacitor and resistors are
connected to these pins. The resistor values are 82
Ω
± 5%. The
capacitor value should be 1.0 µF ± 10% tolerance, X7'R dielectric,
50 volt rating is recommended. (See Figure 13.)
Lock to Reference. Active Low. When active, the serial clock output
will be forced to lock to the local reference clock input [REFCLK].
Serial Data Out. This signal is the delayed version of the incoming
data stream (SERDATI) updated on the falling edge of Serial
Clock Out (SERCLKO).
Serial Clock Out. This signal is phase aligned with Serial Data Out
(SERDATOP/N). (See Figure 7.)
Lock Detect. Clock recovery indicator. Set High when the internal
clock recovery has locked onto the incoming data stream.
LOCKDET is an asynchronous output.
Analog power supply.
Analog GND connection.
Power Supply.
Ground connection connected to exposed heatsink.
BYPASS
I
20
SDN
PECL
I
11
REFCLKP/N
Diff.
PECL
I
8,9
CAP1
CAP2
I
28,27
LCKREFN
TTL
I
10
SERDATOP/N
CM L
O
19,18
SERCLKOP/N
CM L
O
23, 22
LOCKDET
TTL
O
16
AVCC
AVEE
VCC
VEE
+5V
2, 29
3,4,
21,30
12,14,
25
13,15,
26
1, 7, 17,
24,
31, 32
NC
No connection.
April 6, 2000 / Revision NC
5
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
