LT6402CUD-12 LINER [Linear Technology], LT6402CUD-12 Datasheet - Page 10

• Manufacturer Part Number: LT6402CUD-12
• Description: 300MHz Low Distortion, Low Noise Differential Amplifi er/ ADC Driver (AV = 12dB)
• Manufacturer: LINER [Linear Technology]

BLOCK DIAGRAM
LT6402-12
Circuit Description
The LT6402-12 is a low noise, low distortion differential
amplifi er/ADC driver with:
• –3dB bandwidth
• Fixed gain independent of R
• Differential input impedance
• Low output impedance
• Built-in, user adjustable output fi ltering
• Requires minimal support circuitry
APPLICATIONS INFORMATION
10
DC to 300MHz
4V/V (12dB)
100Ω
–INA
–INB
+INA
+INB
14
13
16
15
3
V
LOAD
CCA
100Ω
100Ω
100Ω
100Ω
200Ω
200Ω
10
V
CCB
1
–
+
+
–
V
CCC
A
B
200Ω
200Ω
V
V
V
V
CCA
CCB
EEA
EEB
BIAS
11
V
ENABLE
V
CCC
EEC
Referring to the block diagram, the LT6402-12 uses a
closed-loop topology which incorporates 3 internal am-
plifi ers. Two of the amplifi ers (A and B) are identical and
drive the differential outputs. The third amplifi er is used
to set the output common mode voltage. Gain and input
impedance are set by the 200Ω resistors in the internal
feedback network. Output impedance is low, determined
by the inherent output impedance of amplifi ers A and B,
and further reduced by internal feedback.
The LT6402-12 also includes built-in single-pole output
fi ltering. The user has the choice of using the unfi ltered
outputs, the fi ltered outputs (75MHz –3dB lowpass), or
modifying the fi ltered outputs to alter frequency response
by adding additional components. Many lowpass and
bandpass fi lters are easily implemented with just one or
two additional components.
C
+
–
4
V
EEA
9
14pF
14pF
14pF
50Ω
50Ω
V
EEB
V
V
EEA
EEB
12
V
EEC
5
6
2
7
8
+OUT
+OUTFILTERED
V
–OUTFILTERED
–OUT
64026 BD
OCM
640212fa