OPA325 Low-noise, 10MHz, low-power, zero-crossover precision amplifier | TI.com

OPA325 (ACTIVE) Low-noise, 10MHz, low-power, zero-crossover precision amplifier



The OPA325, OPA2325, and OPA4325 (OPAx325) are precision, low-voltage complementary metal-oxide semiconductor (CMOS) operational amplifiers optimized for very low noise and wide bandwidth, while operating on a low quiescent current of only 650 µA.

The OPAx325 feature a linear input stage with zero-crossover distortion that delivers excellent common-mode rejection ratio (CMRR) of typically 114 dB over the entire input range. The input common-mode range extends 100 mV beyond the negative and positive supply rails. The output voltage typically swings within 10 mV of the rails.

The zero-crossover distortion, combined with wide bandwidth (10 MHz), high slew rate (5 V/µs), and low noise (9 nV/√Hz), make the OPAx325 a very good successive-approximation register (SAR) analog-to-digital converter (ADC) input driver amplifier. In addition, the OPAx325 have a wide supply-voltage range from 2.2 V to 5.5 V, with excellent power-supply rejection ratio (PSRR) over the entire supply range, making the device an excellent choice for precision, low-power applications that run directly from batteries without regulation.

The OPA325 (single-channel version) is available in the SOT23-5 package. The OPA2325 (dual-channel version) is offered in SO-8 and MSOP-8 packages. The OPA4325 (quad-channel version) is available in TSSOP-14 package.


  • Precision with zero-crossover distortion:
    • Low offset voltage: 150 µV (maximum)
    • High CMRR: 114 dB
    • Rail-to-rail I/O
  • Wide bandwidth: 10 MHz
  • Quiescent current: 650 µA/ch
  • Single-supply voltage range: 2.2 V to 5.5 V
  • Low input bias current: 0.2 pA
  • Low noise: 9 nV/√Hz at 10 kHz
  • Slew rate: 5 V/µs
  • Unity-gain stable

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Part number Order Number of channels (#) Total supply voltage (Min) (+5V=5, +/-5V=10) Total supply voltage (Max) (+5V=5, +/-5V=10) GBW (Typ) (MHz) Slew rate (Typ) (V/us) Rail-to-rail Vos (offset voltage @ 25 C) (Max) (mV) Offset drift (Typ) (uV/C) Iq per channel (Typ) (mA) Vn at 1 kHz (Typ) (nV/rtHz) CMRR (Typ) (dB) Rating Operating temperature range (C) Package Group Package size: mm2:W x L (PKG) Input bias current (Max) (pA) Output current (Typ) (mA) Features Architecture
OPA325 Order now 1     2.2     5.5     10     5     In
0.15     2     0.65     10     114     Catalog     -40 to 125     SOT-23 | 5     5SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 5)     10     30     Zero Crossover     CMOS    
OPA340 Order now 1     2.7     5.5     5.5     6     In
0.5     2.5     0.75     25     92     Catalog     -40 to 85     PDIP | 8
SOIC | 8
SOT-23 | 5    
8PDIP: 93 mm2: 9.43 x 9.81 (PDIP | 8)
8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)
5SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 5)    
10     50         CMOS