Texas Instruments OPA627AP Precision Operational Amplifier 8-PDIP Amplifiers

The Texas Instruments OPA627AP remains a benchmark for ultra-low-noise, precision FET op-amps, combining high speed, low distortion, and unmatched DC accuracy. Whether in medical instrumentation, high-end audio, or photonics, its Difet® technology ensures exceptional signal integrity.

The Texas Instruments OPA627AP is a high-performance, FET-input operational amplifier (op-amp) designed for precision instrumentation, medical equipment, high-speed data acquisition, and audiophile-grade applications. Leveraging Difet® (dielectrically isolated FET) technology, this op-amp delivers ultra-low input bias currents (2pA max), exceptional noise performance (4.5nV/√Hz), and precision DC accuracy, making it ideal for ultra-sensitive signal conditioning. With a slew rate of 55V/µs and a 16MHz gain bandwidth product (GBWP), the OPA627AP operates at ±4.5V to ±18V supply ranges, supporting high-speed, low-distortion applications. Packaged in an 8-pin PDIP (through-hole) format, this amplifier is unity-gain stable, ensuring stability in feedback-sensitive designs.

Key Features

• Ultra-Low Input Bias Current (2pA max) – Ideal for photodiode, electrometer, and high-Z sensor applications
• High Speed (55V/µs Slew Rate, 16MHz GBWP) – Accelerates precision signal acquisition
• Low Noise (4.5nV/√Hz @10kHz, 20nV/√Hz @1kHz) – Maximizes SNR in sensitive analog circuits
• Precision DC Performance:

• Low Input Offset Voltage (130µV max)
• Low Drift (0.8µV/°C max) – Stable over industrial temperature ranges (-25°C to +85°C)
  • Wide Supply Range (±4.5V to ±18V) – Supports ±5V, ±12V, ±15V rails
  • High Output Current (45mA) – Drives ADCs, DACs, and low-impedance loads efficiently
  • Unity-Gain Stable (OPA627AP, vs. OPA637AP for gain ±5) – Flexible for buffering and filtering

Technical Specifications

Electrical Characteristics

OPA627AP comparison with alternative parts

Parameter	Value
Gain Bandwidth Product (GBWP)	16MHz
Slew Rate	55V/µs
Input Bias Current (Ib)	2pA (max)
Input Offset Voltage (Vos)	130µV (max), typically <100µV
Voltage Noise Density	4.5nV/√Hz @10kHz
Supply Voltage Range	±4.5V to ±18V (36V total span)
Output Current	45mA (per channel)
Common Mode Rejection (CMRR)	100dB (min)
Power Supply Rejection (PSRR)	100dB (min)
Settling Time to 0.01%	550ns (OPA627AP)

 

Physical & Environmental

Attribute	Details
Package Type	8-PDIP (DIP-8, Through-Hole)
Dimensions	9.81mm × 6.35mm × 5.08mm
Mounting Style	Through-Hole
Pin Count	8
Lead Plating	Gold (low-contact resistance)
Operating Temp. Range	-25°C to +85°C
RoHS Compliance	Compliant (No lead-free variant)

Applications

1. Precision Instrumentation

• Strain gauge amplifiers, thermocouples
• Medical sensors (ECG, EEG, EMG)
• High-impedance pH/chemical sensors

2. High-Speed Data Acquisition

• 16-bit+ ADC/DAC buffer amplifiers
• Ultrasound & sonar signal chains
• Radar/LIDAR analog front-ends

3. Optoelectronics & Sensors

• Photodiode transimpedance amplifiers (TIAs)
• Laser diode control loops
• Low-light CCD/CMOS sensor interfaces

4. High-End Audio & Pro Audio

• Phono preamplifiers (low-noise RIAA EQ)
• Microphone preamps (ultra-low THD+N)
• DAC output stages (for Hi-Res audio)

5. Industrial & Test Equipment

• ATE (Automated Test Equipment) front-ends
• Reference voltage buffers
• Active filter designs (Butterworth, Chebyshev, etc.)

Features

1. Difet® Isolation = Ultra-Low Bias Currents

Unlike conventional FET op-amps, the OPA627AP uses dielectrically isolated FET inputs (Difet®) to reduce input bias currents to femtoampere (fA) levels, eliminating leakage errors common in bipolar/JFET op-amps.

2. 55V/µs Slew Rate for Fast Signal Dynamics

The fast transient response (550ns to 0.01%) ensures minimal phase distortion in pulsed signals, crucial in ultrasound, radar, and high-speed data converters.

3. Low Noise Floor (4.5nV/√Hz @10kHz)

Superior noise performance makes it ideal for weak signal amplification (e.g., bio-sensors, geophones).

4. Unity-Gain Stability (OPA627AP Only)

Unlike the OPA637AP (min gain=5), the OPA627AP remains stable at unity gain, making it perfect for:

• Voltage followers
• I/V converters
• Sensor interface buffers

5. Industrial-Grade Temperature Stability

Low offset drift (0.8µV/°C) ensures precision in fluctuating environments.

OPA627AP vs. Alternatives

OPA627AP comparison with alternative parts

Model	Key Feature	Best For
OPA627AP	Unity-gain stable (GBW=16MHz)	Buffering, low-noise preamps
OPA637AP	Stable at gain ±5 (GBW=80MHz)	High-speed active filters
OPA111	Lower cost, higher bias current	General-purpose precision
LME49710	Bipolar, lower noise (2.7nV/√Hz)	High-fidelity audio