Datasheet
APPLICATIONS
● WIDEBAND PHOTODIODE AMPLIFIERS
● SAMPLE-AND-HOLD BUFFERS
● CCD OUTPUT BUFFERS
● ADC INPUT BUFFERS
● WIDEBAND PRECISION AMPLIFIERS
● TEST AND MEASUREMENT FRONT ENDS
DESCRIPTION
The OPA656 combines a very wideband, unity-gain stable,
voltage-feedback op amp with a FET-input stage to offer an
ultra high dynamic-range amplifier for ADC (Analog-to-Digital
Converter) buffering and transimpedance applications. Extremely
low DC errors give good precision in optical applications.
The high unity-gain stable bandwidth and JFET input allows
exceptional performance in high-speed, low-noise integrators.
The high input impedance and low bias current provided by
the FET input is supported by the ultra-low 7nV/√Hz input
voltage noise to achieve a very low integrated noise in
wideband photodiode transimpedance applications.
Broad transimpedance bandwidths are achievable given the
OPA656’s high 230MHz gain bandwidth product. As shown
below, a –3dB bandwidth of 1MHz is provided even for a high
1MΩ transimpedance gain from a 47pF source capacitance.
FEATURES
● 500MHz UNITY-GAIN BANDWIDTH
● LOW INPUT BIAS CURRENT: 2pA
● LOW OFFSET AND DRIFT: ±0.25mV, ±2µV/°C
● LOW DISTORTION: 74dB SFDR at 5MHz
● HIGH OUTPUT CURRENT: 70mA
● LOW INPUT VOLTAGE NOISE: 7nV/
√Hz
Wideband, Unity-Gain Stable, FET-Input
OPERATIONAL AMPLIFIER
Frequency
1MΩ TRANSIMPEDANCE BANDWIDTH
130
120
110
100
90
80
10kHz 100kHz 1MHz 5MHz
Transimpedance Gain (dB)
1MHz Bandwidth
OPA656
Wideband Photodiode Transimpedance Amplifier
(47pF)
λ
–V
b
499kΩ499kΩ
V
O
1pF
OPA656
SBOS196G – DECEMBER 2001 – REVISED NOVEMBER 2008
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Copyright © 2001-2008, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
OPA656
SLEW VOLTAGE
V
S
BW RATE NOISE
DEVICE (V) (MHz) (V/
µS) (nV/√HZ) AMPLIFIER DESCRIPTION
OPA355 +5 200 300 5.8 Unity-Gain Stable CMOS
OPA655 ±5 400 290 6 Unity-Gain Stable FET-Input
OPA657 ±5 1600 700 4.8 Gain of +7 Stable FET-Input
OPA627 ±15 16 55 4.5 Unity-Gain Stable FET-Input
THS4601 ±15 180 100 5.4 Unity-Gain Stable FET-Input
RELATED OPERATIONAL AMPLIFIER PRODUCTS
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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