THS4508 Datasheet, PDF (1/29 Pages) Texas Instruments – WIDEBAND, LOW NOISE, LOW DISTORTION FULLY DIFFERENTIAL AMPLIFIER

THS4508
www.ti.com
SLAS459A – SEPTEMBER 2005 – REVISED FEBRUARY 2006
WIDEBAND, LOW NOISE, LOW DISTORTION FULLY DIFFERENTIAL AMPLIFIER
FEATURES
• Fully Differential Architecture
• Common-Mode Input Range Includes the
Negative Rail
• Minimum Gain of 2 V/V (6 dB)
• Bandwidth: 2 GHz
• Slew Rate: 6400 V/µs
• 0.1% Settling Time: 2 ns
• HD₂: –72 dBc at 100 MHz
• HD₃: –79 dBc at 100 MHz
• OIP₂: 78 dBm at 70 MHz
• OIP₃: 42 dBm at 70 MHz
• Input Voltage Noise: 2.3 nV/√Hz (f > 10 MHz)
• Noise Figure: 19.2 dB (G = 10 dB)
• Output Common-Mode Control
• 5-V Power Supply Current: 39.2 mA
• Power-Down Capability: 0.65 mA
APPLICATIONS
• 5-V Data-Acquisition Systems
• High Linearity ADC Amplifier
• Wireless Communication
• Medical Imaging
• Test and Measurement
DESCRIPTION
The THS4508 is a wideband, fully-differential
operational amplifier designed for single-supply 5-V
data-acquisition systems. It has very low noise at 2.3
nV/√Hz, and extremely low harmonic distortion of –72
dBc HD₂ and –79 dBc HD₃ at 100 MHz with 2 V_PP,
G = 10 dB, and 1-kΩ load. Slew rate is very high at
6400 Vµs and with settling time of 2 ns to 0.1% (2 V
step) it is ideal for pulsed applications. It is designed
for minimum gain of 6 dB, but is optimized for gain of
10 dB.
To allow for dc coupling to ADCs, its unique output
common-mode control circuit maintains the output
common-mode voltage within 5-mV offset (typical)
from the set voltage, when set within 0.5 V of
mid-supply. The common-mode set point is set to
mid-supply by internal circuitry, which may be
over-driven from an external source.
The THS4508 is a high-performance amplifier that
has been optimized for use in high performance, 5-V
single supply data acquisition systems. The output
has been optimized for best performance with its
common-mode voltages set to mid supply, and the
input has been optimized for best performance with
its common-mode voltage set to 0.7 V. High
performance at a low power-supply voltage makes for
high-performance single-supply 5-V data-acquisition
systems with a minimum parts count. The combined
performance of the THS4508 in a gain of 10-dB
driving the ADS5500 ADC, sampling at 125 MSPS, is
82-dBc SFDR, and 68.3-dBc SNR with a –1-dBFS
signal at 70 MHz.
The THS4508 is offered in a Quad 16-pin leadless
QFN package (RGT), and is characterized for
operation over the full industrial temperature range
from –40°C to 85°C.
R_S = 75 W V_IN 175 W
V_Signal
130 W
348 W
V_S+ = 5 V
75 W
175 W
130 W
THS4508
V_S-
V_CM
R_O
V_OUT-
R_O
V_OUT+
348 W
Figure 1. Video Buffer
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Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005–2006, Texas Instruments Incorporated