LT1969 Datasheet, PDF (1/20 Pages) Linear Technology – Dual 700MHz, 200mA, Adjustable Current Operational Amplifier

LT1969
Dual 700MHz, 200mA,
Adjustable Current Operational Amplifier
FEATURES
s _{700MHz Gain Bandwidth}
s _{±200mA Minimum IOUT}
s _{Adjustable Quiescent Current}
s _{Low Distortion: –72dBc at 1MHz, 4VP-P, 25Ω, AV = 2}
s _{Stable in AV ≥ 10, Simple Compensation for AV < 10}
s _{±4.3V Minimum Output Swing, VS = ±6V, RL = 25Ω}
s _{Stable with 1000pF Load}
s _{6nV/√Hz Input Noise Voltage}
s _{2pA/√Hz Input Noise Current}
s _{4mV Maximum Input Offset Voltage}
s _{4µA Maximum Input Bias Current}
s _{400nA Maximum Input Offset Current}
s _{±4.5V Minimum Input CMR, VS = ±6V}
s _{Specified at ±6V, ±2.5V}
U
APPLICATIO S
s _{DSL Modems}
s _{xDSL PCI Cards}
s _{USB Modems}
s _{Line Drivers}
DESCRIPTIO
The LT^®1969 is an adjustable current version of the
popular LT1886, a 200mA minimum output current, dual
op amp with outstanding distortion performance. The
adjustable current feature is highly desirable in applica-
tions where minimum power dissipation is required while
still being able to provide adequate line termination.
At nominal supply current, the amplifiers are gain of 10
stable and can easily be compensated for lower gains. The
LT1969 features balanced high impedance inputs with
4µA input bias current and 4mV maximum input offset
voltage. Single supply applications are easy to implement
and have lower total noise than current feedback amplifier
implementations.
The output drives a 25Ω load to ±4.3V with ±6V supplies.
On ±2.5V supplies, the output swings ±1.5V with a 100Ω
load. The amplifier is stable with a 1000pF capacitive load
making it useful in buffer and cable driver applications.
The LT1969 is manufactured on Linear Technology’s
advanced low voltage complementary bipolar process and
is available in a thermally enhanced MS10 package
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Single 12V Supply ADSL Modem Line Driver
12V
0.1µF
IN ⁺
10k 20k
+
1/2 LT1969
–
909Ω
12.4Ω
100Ω
1:2*
*COILCRAFT X8390-A
OR EQUIVALENT
1µF 10k 20k
0.1µF
IN ^–
1µF 100Ω
909Ω
–
1/2 LT1969
+
12.4Ω
100Ω
CTRL1 CTRL2
6
7
I_Q ON = 14mA
I_Q LOW POWER = 2mA
I_Q STANDBY = 600µA
13k 49.9k STANDBY ON
STANDBY
LOW POWER ON
LOGIC
OUTPUT
1969 TA01a
ADSL Modem Line Driver Distortion
–60
V_S = 12V
A_V = 10
f = 200kHz
–70 100Ω LINE
1:2 TRANSFORMER
HD2
–80
–90
HD3
–100
0 2 4 6 8 10 12 14 16
LINE VOLTAGE (V_P-P)
1969 TA01b
1