
24
LT1251/LT1256
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977
LT/GP 0896 REV A 5K PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1994
TYPICAL APPLICATIONS
U
4-Quadrant Multiplier as a Double-Sideband Suppressed-Carrier Modulator
Modulation Gain vs Control Voltage
–
+
–
+
1MHz
CARRIER
MODULATION
10k
10k*
RF2
1.5k
VOUT
RF1
1.5k
IC
V+
V–
1251/56 TA04a
2
–
+
–
+
1
2
3
4
5
6
7
14
13
12
11
10
9
8
CONTROL
LT1256
1
CFS
5k
IFS
0.1
F
0.1
F
*TRIM FOR SYMMETRY
2.5VDC
INPUT
RG1
1.5k
CONTROL VOLTAGE, PIN 3 (V)
0
GAIN
(V/
V)
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
2.0
1251/56 TA04b
0.5
1.0
1.5
2.5
VS = ±5V
VFS = 2.5V
1.5k
1N914
1k
5k
VIN
1251/56 TA10a
2
8
200pF
2.5VDC
INPUT
14
13
12
10
5
3
1
VOUT
VC
RC
RFS
VFS
LT1256
–
+
–
+
2
1
9
7
V+
V–
Soft Clipper
VFS = 2.5V
VS = ±5V
f = 1kHz
1251/56 TA10b
VIN
VOUT
PART NUMBER
DESCRIPTION
COMMENTS
LT1228
100MHz Current Feedback Amplifier with DC Gain Control
Includes a 75MHz Transconductance Amplifier
LT1252
Low Cost Video Amplifier
100MHz Bandwidth
LT1253/LT1254
Low Cost Dual and Quad Video Amplifiers
90 MHz Bandwidth
LT1259/LT1260
Low Cost Dual and Triple 130MHz Current Feedback
Makes Fast Video MUX
Amplifiers with Shutdown
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