ATA00501
APPLICATION INFORMATION
V
DD
NC
0.1µF
V
DD
12
56pF
11
10
GND
56pF
VDD2
NC
1
2
9
8
7
NC
GND
V
DD
PIN
60C
I
IN
GND
1992
I
IN
OUT
3
0.1µF
Vout
GND
V
OUT
GND
GND
GND
C
BY
C
BY
GND
C
AGC
GND
GND
or
Neg.Supply
4
5
6
56pF
56pF
56 pF
56 pF
Figure 4: ATA 00501D1C Typical Bonding
Figure 5: ATA 00501S2C External Circuit
Bandwidth (GHz)
Power Supplies and General Layout
Considerations
The ATA00501S2C may be operated from a positive
supply as low as + 4.5 V and as high as + 6.0 V.
Below + 4.5 V, bandwidth, overload and sensitivity
will degrade, while at + 6.0 V, bandwidth, overload
and sensitivity improve (see Bandwidth vs.
Temperature curves). Use of surface mount, low
inductance power supply bypass capacitors
(>=56pF) are essential for good high frequency and
low noise performance. The power supply bypass
capacitors should be mounted on or connected to a
good low inductance ground plane.
General Layout Considerations
Since the gain stages of the transimpedance
amplifier have an open loop bandwidth in excess
of 1.0 GHz, it is essential to maintain good high
frequency layout practices. To prevent oscillations,
a low inductance RF ground plane should be made
available for power supply bypassing. Traces that
can be made short should be made short, and the
utmost care should be taken to maintain very low
capacitance at the photodiode-TIA interface (I
IN
),
excess capacitance at this node will cause a
41.
degradation in bandwidth and sensitivity (see
Bandwidth vs. CT curves).
Figure 6: Bandwidth vs. Temperature
C
T
= 0.5 pF
0.09
0.08
0.07
0.06
0.05
0.04
-40
10
60
85
V
DD
=
5.5 V
V
DD
=
5.0 V
V
DD
=
4.5 V
Temperature (C)
PRELIMINARY DATA SHEET - Rev 1.5
08/2001
ANADIGICS [ ANADIGICS, INC ]
