LT5524 Datasheet, PDF (1/16 Pages) Linear Technology – Low Distortion IF Amplifier/ADC Driver with Digitally Controlled Gain

FEATURES
■ _{Output IP3 at 100MHz: 40dBm}
■ _{Maximum Output Power: 16dBm}
■ _{Bandwidth: LF to 540MHz}
■ _{Propagation Delay: 0.8ns}
■ _{Maximum Gain: 27dB}
■ _{Gain Control Range: 22.5dB}
■ _{Gain Control Step: 1.5dB}
■ _{Gain Control Settling Time: 500ns}
■ _{Noise Figure: 8.6dB at 100MHz (Max Gain)}
■ _{Output Noise Floor: –138dBm/Hz (Max Gain)}
■ _{Reverse Isolation: –92dB}
■ _{Single Supply: 4.75V to 5.25V}
■ _{Shutdown Mode}
■ _{Enable/Disable Time: 1µs}
■ _{Differential I/O Interface}
■ _{20-Lead TSSOP Package}
U
APPLICATIO S
■ _{High Linearity ADC Driver}
■ _{IF Sampling Receivers}
■ _{VGA IF Power Amplifier}
■ _{50Ω Driver}
■ _{Instrumentation Applications}
LT5524
Low Distortion IF
Amplifier/ADC Driver with
Digitally Controlled Gain
DESCRIPTIO
The LT^®5524 is a programmable gain amplifier (PGA) with
bandwidth extending from low frequency (LF) to 540MHz.
It consists of a digitally controlled variable attenuator,
followed by a high linearity amplifier. Four parallel digital
inputs control the gain over a 22.5dB range with 1.5dB
step resolution. An on-chip power supply regulator/filter
helps isolate the amplifier signal path from external noise
sources.
The LT5524’s open-loop architecture offers stable opera-
tion for any practical load conditions, including peaking-
free AC response when driving capacitive loads, and
excellent reverse isolation.
The LT5524 may be operated broadband, where the out-
put differential RC time constant sets the bandwidth, or it
may be used as a narrowband driver with the appropriate
output filter.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Patents Pending.
TYPICAL APPLICATIO
0.1µF
CHOKE
5V
CHOKE
0.1µF
RF
INPUT
IF
IF
BPF AMP
LT5524
100Ω
LO
0.1µF
0.1µF
GAIN CONTROL
4 LINES
ADC
5524 TA01
Output IP3 vs Frequency, R_OUT = 200Ω
54
51
48
45
MAX GAIN
42
39
1.5dB
36 ATTENUATION
STEP
33
30
0
50
100
150
200
FREQUENCY (MHz)
5524 TA02
5524f
1