ATA12001
APPLICATION INFORMATION
VDD
0.1
f
µ
0.1 F
µ
CAGC
VDD
AGC
RF
4pf
700 MHz
NOISE FILTER
4K
CDET
0.4pF
0.1 F
µ
I-IN
50
20 nH
5pF
Ω
DET-BYP
AV=-35
20pF
R
18pF
CBY
GND
50
Ω
.01
f
µ
Figure 4: Typical Application HIPPI 1 Gb/s
excess capacitance at this node will cause a
degradation in bandwidth and sensitivity (see
Bandwidth vs. CT curves).
Power Supplies and General Layout Considerations
The ATA12001D1C 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
(preferably MIM type capacitors), 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.
CT = 0.5 pF
1.3
5.5 V
VDD =
1.2
1.1
1.0
0.9
VDD = 5.0 V
General Layout Considerations
Since the gain stages of the transimpedance
amplifier have an open loop bandwidth in excess of
1.5 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 (IIN), as
4.5 V
VDD=
-40
10
60
85
Temperature (OC)
Figure 4: Bandwidth vs. Temperature
PRELIMINARY DATA SHEET - Rev 4
08/2001
4
ANADIGICS [ ANADIGICS, INC ]
