SY88943V_05 Datasheet, PDF (1/6 Pages) Micrel Semiconductor – 5V/3.3V 2.5Gbps LIMITING POST AMPLIFIER WITH SIGNAL DETECT

Micrel, Inc.
5V/3.3V 2.5Gbps
LIMITING POST AMPLIFIER
WITH SIGNAL DETECT
SY88943V
SY88943V
FEATURES
s 3.3V and 5V power supply options
s Up to 2.5Gbps operation
s Low noise
s Chatter-fee signal detect (SD) generation
s Open collector TTL signal detect (SD) output
s TTL EN input
s Differential PECL inputs for data
s Single power supply
s Designed for use with Micrel-Synergy laser diode
driver and controller
s Available in a tiny (3mm) 10-pin MSOP
APPLICATIONS
s 1.25Gbps and 2.5Gbps ethernet
s 531Mbps, 1062Mbps and 2.12Gbps Fibre Channel
s 622Mbps SONET
s Gigabit interface converter
s 2.5Gbps SDH/SONET
s 2.5Gbps proprietary links
DESCRIPTION
The SY88943V limiting post amplifier with its high gain
and wide bandwidth is ideal for use as a post amplifier in
fiber-optic receivers with data rates up to 2.5Gbps.
Signals as small as 5mVp-p can be amplified to drive
devices with PECL inputs. The SY88943V generates a
chatter-free Signal Detect (SD) open collector TTL output.
The SY88943V incorporates a programmable level detect
function to identify when the input signal has been lost.
The SD output will change from logic “HIGH” to logic “LOW”
when input signal is smaller than the swing set by SD_LVL.
This information can be fed back to the EN input of the
device to maintain stability under loss of signal condition.
Using SD_LVL pin, the sensitivity of the level detection can
be adjusted. The SD_LVL voltage can be set by connecting
a resistor divider between V_CC and V_REF as shown in Figure
3. Figure 4, 5, 6, and 7 show the relationship between
input level sensitivity and the voltage set on SD_LVL.
The SD output is a TTL open collector output that
requires a pull-up resistor for proper operation, Figure 1.
SY88943V
SD
V_CC
4.7kΩ to 10kΩ
BLOCK DIAGRAM
D_IN
Limiting
/D_IN
Amplifer
V_REF
V_CC
GND
SD_LVL
M9999-082205
[e-mail] or [phone]
Figure 1. SD Output with Desired Rise Time
ECL
Buffer
Enable
D_OUT
/D_OUT
EN
Level
Detect
SD
1
Rev.: C Amendment: /0
Issue Date: August 2005