LT1251 Datasheet, PDF (15/24 Pages) Linear Technology – 40MHz Video Fader and DC Gain Controlled Amplifier

TYPICAL APPLICATIONS
AM Modulator with DC Output Nulling Circuit
LT1251/LT1256
1MHz
CARRIER
2.5VDC
INPUT
220k
AUDIO
MODULATION
0.1µF
50Ω
0.1µF
220k
1
2
3
4
5
NULL 6
V^{– 7}
LT1256
+
1
2
–
CONTROL
+
C
I_C IFS
FS
–
5k
5k
V⁺
0.1µF
14
13
12
11
10
9 _V+
8
R_F2 R_F1
1.5k 1.5k
220k
V_OUT
LT1077
1251/56 TA03
V^–
Single Supply Inverting AC Amplifier
C1
10µF ^RG1
R_F1
+ ^1.5k
1.5k
V1
R1
20k
V⁺
R2 ⁺
20k
2
1
C_O
10µF 14
13
LT1251/LT1256
–
1
+
8
+
V^{+ 9} 5V
2
–
V^{– 7}
V_OUT
V_C R_C R_FS V_FS
3 5 10 12
C2
10µF
R_G2
V2
+ ^1.5k
CONTROL
2.5VDC
VOLTAGE _RF2 ^INPUT
1.5k
1251/56 TA05
Single Supply Noninverting AC Amplifier
with Digital Gain Control
10µF
R_G1
R_F1
+ ^1.5k
1.5k
10µF
V1
+
10µF
V2
+
10k
20k
5V
20k
LT1251/LT1256
2
–
1
1
+
8
14 ₊
13 2
10k
–
V^{+ 9} 5V
V^{– 7}
+
10µF
V_C R_C R_FS V_FS
3 5 10 12
10µF
+
R_G2
R_F2
1.5k
1.5k
V_OUT
V_REF
D_IN
V_OUT LTC1257 ^CLK
LOAD
GND V_CC
5V
µP
1251/56 TA06
15