Overview
The AD8638ARZ-REEL, produced by Analog Devices Inc., is a single, wide bandwidth, auto-zero operational amplifier. This component is part of the AD8638/AD8639 series, known for its high accuracy, low noise, and rail-to-rail output swing. It combines the benefits of low cost with the performance characteristics previously found only in more expensive zero-drift or chopper-stabilized amplifiers. The AD8638ARZ-REEL is particularly suited for applications where low offset voltage, drift, and bias current are critical.
Key Specifications
| Parameter | Value | Conditions |
|---|---|---|
| Supply Voltage | 5 V to 16 V (single-supply), ±2.5 V to ±8 V (dual-supply) | |
| Offset Voltage | 3 μV (typical), 9 μV (maximum) | |
| Offset Voltage Drift | 0.01 μV/°C (typical), 0.04 μV/°C (maximum) | −40°C ≤ TA ≤ +125°C |
| Input Bias Current | 40 pA (maximum) | |
| Supply Current | 1.3 mA (maximum) | |
| Gain | 136 dB (typical) | |
| CMRR | 133 dB (typical) | |
| PSRR | 143 dB (typical) | |
| Input Resistance | 22.5 TΩ | |
| Input Capacitance (Differential Mode) | 4 pF | |
| Input Capacitance (Common Mode) | 1.7 pF | |
| Output Voltage High | 4.97 V (RL = 10 kΩ to VCM) | −40°C ≤ TA ≤ +125°C |
| Gain Bandwidth Product | 1.35 MHz (RL = 2 kΩ, CL = 20 pF, AV = 1) | |
| Phase Margin | 70 Degrees (RL = 2 kΩ, CL = 20 pF, AV = 1) | |
| Voltage Noise (0.1 Hz to 10 Hz) | 1.2 μV p-p | |
| Voltage Noise Density | 60 nV/√Hz (f = 1 kHz) |
Key Features
- Auto-zero topology for low offset voltage and drift
- Rail-to-rail output swing
- Low noise operation: 1.2 μV p-p (0.1 Hz to 10 Hz), 60 nV/√Hz (at 1 kHz)
- High gain: 136 dB typical
- High CMRR and PSRR: 133 dB and 143 dB typical, respectively
- Very low input bias current: 40 pA maximum
- Low supply current: 1.3 mA maximum
- No external capacitors required
- Wide operating temperature range: −40°C to +125°C
Applications
- Pressure and position sensors
- Strain gage amplifiers
- Medical instrumentation
- Thermocouple amplifiers
- Automotive sensors (AD8639 is qualified for automotive applications)
- Precision references
- Precision current sensing
Q & A
- What is the typical offset voltage of the AD8638ARZ-REEL?
The typical offset voltage is 3 μV, with a maximum of 9 μV. - What is the operating temperature range of the AD8638ARZ-REEL?
The operating temperature range is −40°C to +125°C. - Does the AD8638ARZ-REEL require external capacitors?
No, the AD8638ARZ-REEL does not require external capacitors. - What is the maximum input bias current of the AD8638ARZ-REEL?
The maximum input bias current is 40 pA. - What are the typical CMRR and PSRR values of the AD8638ARZ-REEL?
The typical CMRR is 133 dB, and the typical PSRR is 143 dB. - What is the gain bandwidth product of the AD8638ARZ-REEL?
The gain bandwidth product is 1.35 MHz (RL = 2 kΩ, CL = 20 pF, AV = 1). - What are some common applications of the AD8638ARZ-REEL?
Common applications include pressure and position sensors, strain gage amplifiers, medical instrumentation, thermocouple amplifiers, and automotive sensors. - What is the maximum supply current of the AD8638ARZ-REEL?
The maximum supply current is 1.3 mA. - What is the phase margin of the AD8638ARZ-REEL?
The phase margin is 70 Degrees (RL = 2 kΩ, CL = 20 pF, AV = 1). - What is the voltage noise density of the AD8638ARZ-REEL at 1 kHz?
The voltage noise density is 60 nV/√Hz at 1 kHz.
