tza3026 NXP Semiconductors, tza3026 Datasheet - Page 4

• Manufacturer Part Number: tza3026
• Description: Tza3026 Sdh/sonet Stm4/oc12 Transimpedance Amplifier
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 2:
Bonding pad locations with respect to the center of the die (see
[1]
7. Functional description
9397 750 14763
Product data sheet
Symbol
GND
GND
OUTQ
OUT
AGC
IDREF_MON
V
CC
These pads go HIGH when current flows into pad IPHOTO.
Bonding pad description
Pad X
11
12
13
14
15
16
17
7.1 PIN diode connections
486.4
346.4
206.4
66.4
73.6
213.6
353.6
The TZA3026 is a TransImpedance Amplifier (TIA) intended for use in fiber optic receivers
for signal recovery in STM4/OC12 or FTTx applications. It amplifies the current generated
by a photo detector (PIN diode or avalanche photodiode) and converts it to a differential
output voltage.
The most important characteristics of the TZA3026 are high receiver sensitivity, wide
dynamic range and large bandwidth. Excellent receiver sensitivity is achieved by
minimizing transimpedance amplifier noise.
The TZA3026 has a wide dynamic range to handle the signal current generated by the
PIN diode which can vary from 0.85 A to 1.5 mA (p-p). This is implemented by an AGC
loop which reduces the preamplifier feedback resistance so that the amplifier remains
linear over the whole input range. The AGC loop hold capacitor is integrated on-chip, so
an external capacitor is not required.
The bandwidth of TZA3026 is optimized for STM4/OC12 application. It works from DC
onward due to the absence of offset control loops. Therefore the amount of Consecutive
Identical Digits (CID) will not effect the output waveform. A differential amplifier converts
the output of the preamplifier to a differential voltage.
The performance of an optical receiver is largely determined by the combined effect of the
transimpedance amplifier and the PIN diode. In particular, the method used to connect the
PIN diode to the input (pad IPHOTO) and the layout around the input pad strongly
influences the main parameters of a transimpedance amplifier, such as sensitivity,
bandwidth, and PSRR.
Sensitivity is most affected by the value of the total capacitance at the input pad.
Therefore, to obtain the highest possible sensitivity the total capacitance should be as low
as possible.
Y
278.6
278.6
278.6
278.6
278.6
278.6
278.6
…continued
Type
ground
ground
output
output
input
output
supply
Rev. 01 — 2 May 2005
Description
ground; connect together pads 9, 10, 11 and pad 12 as many as
possible
ground; connect together pads 9, 10, 11 and pad 12 as many as
possible
data output; complement of pad OUT; use pad 7 or pad 13
data output; use pad 8 or pad 14
AGC voltage; use pad 6 or pad 15
current output for RSSI measurements; connect a resistor to pad 5
or pad 16 and ground
supply voltage; connect supply voltage to pad 4 or pad 17
Figure
SDH/SONET STM4/OC12 transimpedance amplifier
10), X and Y are in m.
[1]
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
TZA3026
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