ISL55211 Datasheet, PDF (1/20 Pages) Intersil Corporation – Wideband, Low Noise, Low Distortion, Fixed Gain, Differential Amplifier

Wideband, Low Noise, Low Distortion, Fixed Gain,
Differential Amplifier
ISL55211
The ISL55211 is a wideband, differential input to differential
output amplifier offering 3 possible internal gain settings.
Using fixed 500Ω internal feedback resistors, the amplifier
may be configured for a differential gain of 2, 4 or 5V/V
depending on which combination of input pins are connected
to the signal source. Internal feedback capacitors controls the
signal bandwidth to be a constant 1.4GHz in all gain settings.
Ideally suited for AC-coupled data acquisition applications, the
output DC common mode voltage is controlled through an
external V_CM pin or left to default to 1.2V above the negative
supply pin. Where the differential signal source is AC-coupled,
the input common mode voltage will equal the output
common mode voltage.
Intended for very high dynamic range ADC interface
applications, the ISL55211 offers 5600V/µs differential slew
rate, <12nV/√Hz output noise, and >100dBc SFDR to
>100MHz for 2V_P-P 2-tone 3rd order intermodulation. Its
balanced architecture effectively suppresses even order
distortion terms - an important issue for very wide band 1st
Nyquist zone ADC interface applications. Minimum gain
operation of 2V/V (6dB) with <1dB peaking ensures stable
performance over-temperature. It's ultra high differential slew
rate of 5600V/µs provides adequate performance margin for
large signal application through 500MHz.
The ISL55211 requires only a single 3.3V (max. 4.2V) power
supply and 35mA quiescent current, providing a very low
power solution (115mW). Further power savings are possible
using the optional power shutdown control - where the
quiescent current can be reduced to <0.4mA. A companion
device, the ISL55210, offers similar performance where the
feedback and gain resistors are external. Both are available in
a 16 Ld TQFN (Pb-free) package and are specified for
operation over the -40°C to +85°C ambient temperature
range.
Features
• 3 Fixed Gain Options . . . . . . . . . . . . . . . . . . . . . . . 2, 4, or 5V/V
• Constant Bandwidth Over Gain . . . . . . . . . . . . . . . . . . 1.4GHz
• Differential Slew Rate . . . . . . . . . . . . . . . . . . . . . . . 5,600V/µs
• 2V_P-P, 2-tone IM3 (200Ω) 100MHz . . . . . . . . . . . . . . -103dBc
• Low Differential Output Noise (Gain 5V/V) . . . . . . <12nV/√Hz
• Supply Voltage Range . . . . . . . . . . . . . . . . . . . . . . 3.0V to 4.2V
• Quiescent Power (3.3V Supply) . . . . . . . . . . . . . . . . . .115mW
Applications
• Low Power, High Dynamic Range ADC Interface
• Differential Mixer Output Amplifier
• SAW Filter Pre/Post Driver
• Fixed Gain Coax Receiver
Related Devices
• ISL55210 - External Gain Set Version
• ISLA112P50 - 12-bit, 500MSPS ADC (<500mW)
• ISLA214P50 - 14-bit, 500MSPS ADC (<850mW)
Related Literature
• AN1649 - “Designer’s guide to the ISL55210 and ISL55211
Evaluation Boards”
+3.3V
V_{i 1:2}
50
VCM
1.2V
ADT4-1T
35mA
(115mW)
+
ISL55211
G = 5V/V
10 ADT2-1T50
1:1.4
22pF
120nH
VADC
ISLA214P50
(850mW)
14Bit 500MSPS
300
8pF
120nH
180mVP-P
-
10
50
VCM
For ADC -1dBFS
20 logV^ADC = 20dB
Vi
HIGH GAIN, VERY LOW POWER, ADC INTERFACE WITH 3^RD ORDER OUTPUT FILTER
23
MEASURED FREQUENCY RESPONSE
20
17
14
11
8
5
2
-1
-4
-7
-10
-13
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 1. TYPICAL APPLICATION CIRCUIT
June 21, 2011
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
FN7868.0
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