Data Sheet
February 1999
LG1605DXB Limiting Amplifier
6
Lucent Technologies Inc.
Test Circuit
12-3215(F)r.6
1. Depending on the desired supply rejection, V
BR
can be biased with a simple resistive divider, or resistor/zener diode network.
Alternatively, when the LG1605DXB is followed by the LG1600 clock and data regenerator, a resistive divider with bypassing capacitor may
be connected to pin 7 (V
REF
) of the LG1600 (V
REF
≈
–3.2 V). This arrangement provides excellent temperature stability and power supply
rejection.
2. The outputs may be either ac coupled, as indicated, or dc terminated into 50
. In the first case, good output return loss (see Figure 8) can be
obtained. The latter configuration provides a 0 mV to –600 mV output swing (when limiting) for easy interface to dc-coupled circuits. No input
coupling capacitors are needed when interfacing with the LG1600 or the 1319 receiver.
Figure 3. LG1605DXB Test Circuit (with TF1003C Test Fixture)
12-3216(F)r.3
1. Depending on the desired supply rejection, V
BR
can be biased with a simple resistive divider, or resistor/zener diode network.
Alternatively, when the LG1605DXB is followed by the LG1600 clock and data regenerator, a resistive divider with bypassing capacitor may
be connected to pin 7 (V
REF
) of the LG1600 (V
REF
≈
–3.2 V). This arrangement provides excellent temperature stability and power supply
rejection.
Figure 4. Bias Options
110 pF
25 k
110 pF
–
+
13
14
2
3
V
–OUT
CHIP BOUNDARY
GND
1, 4, 5, 6, 15, 16
7
V
BR
8
+
–
–
+
9
10
11
12
110 pF
50
V
SS
V
+OUT
V
BS
V
BF
V
+REF
V
+IN
V
–IN
V
–REF
25 k
+
–
–
+
50
50
50
5
5
LG1605DXB
SOURCE
0.047
μ
F
0.047
μ
F
50
50
LOAD
(SEE NOTE 2)
TF1003C FIXTURE BOUNDARY
0.047
μ
F
+
1.5 V
R
INT
≤
10 k
(SEE NOTE 1)
+
5.2 V
5
0.047
μ
F
0.047
μ
F
0.047
μ
F
0.047
μ
F
0.047
μ
F
(SEE NOTE 1)
12 k
≈
–3.2 V
(PIN 7 LG1600)
13.6 k
–1.5 V
A.
Using LG1600 Reference Voltage
B.
Using Supply Voltage
V
REF
V
BR
0.047
μ
F
(SEE NOTE 1)
8.2 k
–5.2 V
20 k
–1.5 V
V
SS
V
BR