The OPA657 device combines a high-gain bandwidth, low-distortion, voltage-feedback operational amplifier with a low-voltage noise JFET-input stage to offer a very high dynamic range amplifier for high-precision ADC (analog-to-digital converter) driving or wideband transimpedance applications. Photodiode applications see improved noise and bandwidth using this decompensated, high-gain bandwidth amplifier.
Very low level signals can be significantly amplified in a single OPA657 gain stage with exceptional bandwidth and accuracy. Having a high 1.6-GHz gain bandwidth product gives greater than 10-MHz signal bandwidths up to gains of 160 V/V (44 dB). The very low input bias current and capacitance supports this performance even for relatively high source impedances.
Broadband photodetector applications benefit from the low-voltage noise JFET inputs for the OPA657. The JFET input contributes virtually no current noise while for broadband applications, a low voltage noise is also required. The low 4.8 nV/√Hz input voltage noise provides exceptional input sensitivity for higher bandwidth applications. The example shown below gives a total equivalent input noise current of 1.8 pA/√Hz over a 10-MHz bandwidth.
|Part number||Order||Architecture||Number of channels (#)||Total supply voltage (Min) (+5V=5, +/-5V=10)||Total supply voltage (Max) (+5V=5, +/-5V=10)||BW @ Acl (MHz)||Acl, min spec gain (V/V)||Slew rate (Typ) (V/us)||Vn at flatband (Typ) (nV/rtHz)||Vn at 1 kHz (Typ) (nV/rtHz)||Iq per channel (Typ) (mA)||Vos (offset voltage @ 25 C) (Max) (mV)||Rail-to-rail||Features||Rating||Operating temperature range (C)||Package Group||Package size: mm2:W x L (PKG)||CMRR (Typ) (dB)||Input bias current (Max) (pA)||Offset drift (Typ) (uV/C)||GBW (Typ) (MHz)||Output current (Typ) (mA)||2nd harmonic (dBc)||3rd harmonic (dBc)||@ MHz|
FET / CMOS Input
|1||8||12||350||7||700||4.8||7||14||1.8||No||Decompensated||Catalog||-40 to 85||
SOIC | 8
SOT-23 | 5
8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)
5SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 5)
FET / CMOS Input
|1||6||13||790||7||1400||2.2||8.5||27.7||1.25||No||Decompensated||Catalog||-40 to 125||SON | 8||8SON: 9 mm2: 3 x 3 (SON | 8)||90||20||3||2700||60||-90||-96||1|