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Analog Devices Inc. AD8638ARZ
- Part No.:
- AD8638ARZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
AD8638ARZ.pdf
- Description:
- IC OPAMP ZERO-DRIFT 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:545
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Product details
Overview
AD8638ARZ from Analog Devices is a single-channel, auto-zero, rail-to-rail output operational amplifier optimized for precision DC-coupled measurement systems. It delivers 9 μV max offset voltage, 0.04 μV/°C max drift (SOT-23), and 1.3 mA max supply current across a 5 V to 16 V single-supply range. It is widely deployed in strain gage amplifiers and thermocouple signal conditioning where near-zero drift over −40°C to +125°C is critical.
For engineers reviewing the AD8638ARZ datasheet, AD8638ARZ pinout, AD8638ARZ application, or AD8638ARZ equivalent, key selection criteria include verified auto-zero performance at 16 V operation, confirmed SOT-23-5 package compatibility, guaranteed rail-to-rail output swing down to 10 mV from rails, and documented 1.2 μVp-p (0.1–10 Hz) noise - all validated per Rev. F specification.
Technical Context
The AD8638ARZ employs a patented dual-stage auto-zero + chopping ping-pong architecture operating at ~15 kHz, eliminating 1/f noise while suppressing switching artifacts. Its input stage uses high-impedance CMOS with 22.5 TΩ input resistance and 4 pF differential capacitance, enabling ultra-low bias current (≤40 pA).
This topology achieves 136 dB typical open-loop gain, 133 dB typical CMRR, and 143 dB typical PSRR - all specified across −40°C to +125°C - with overload recovery under 50 μs due to synchronized nulling loop reset within two clock cycles after saturation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset Voltage | 3 μV typical / 9 μV max - enables ≥1000× closed-loop gain without output error exceeding 9 mV. |
| Offset Drift | 0.04 μV/°C max (SOT-23) - ensures ≤0.5 μV total drift over full −40°C to +125°C industrial range. |
| Supply Range | 5 V to 16 V single-supply - supports direct interface with 12 V industrial sensors and 15 V DAC references. |
| Output Swing | Rail-to-rail - delivers 4.97 VH/15.94 VH and 10 mVL/40 mVL at 10 kΩ load, maximizing dynamic range in 5 V/16 V systems. |
| Input Bias Current | 40 pA max - permits use with >100 MΩ source impedances (e.g., piezoresistive pressure sensors) without significant error. |
| Low-Frequency Noise | 1.2 μVp-p (0.1–10 Hz) - eliminates 1/f noise internally, removing need for external filtering in precision DC measurements. |
| Gain Bandwidth | 1.35 MHz (5 V) / 1.5 MHz (16 V) - supports stable unity-gain operation with 20 pF capacitive loads and 2 kΩ resistive loads. |
Pinout & Package
AD8638ARZ is packaged in an 8-lead SOIC_N (R-8) with exposed thermal pad connected to V−. Pin 4 and the exposed pad must be soldered to V− for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT | Amplifier output node; rail-to-rail capable, drives up to ±19 mA short-circuit current. |
| 2 | V− | Negative supply terminal; must connect to exposed thermal pad for thermal management and PSRR stability. |
| 3 | +IN | Noninverting input; high-impedance CMOS node with 22.5 TΩ resistance and 1.7 pF common-mode capacitance. |
| 4 | V+ | Positive supply terminal; accepts 5 V to 16 V; PSRR of 143 dB minimizes supply ripple coupling. |
| 5 | −IN | Inverting input; matched to +IN for <23 μV max offset over temperature; requires input voltage within −0.1 V to +14 V at 16 V supply. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-zero + chopping architecture | 15 kHz ping-pong clock eliminates 1/f noise and reduces switching artifacts - no external capacitor required. |
| Rail-to-rail output stage | Delivers 10 mV low / 4.97 V high at 5 V supply, preserving >99% of full-scale signal range for ADC interfacing. |
| Extended temperature grade | Specified from −40°C to +125°C - qualified for automotive sensor front-ends and industrial control modules. |
| High PSRR/CMRR | 143 dB PSRR and 133 dB CMRR ensure immunity to supply ripple and common-mode interference in noisy environments. |
| No external components | Stable with 20 pF capacitive loads; no compensation network needed - simplifies PCB layout and reduces BOM count. |
Applications
| Pressure Sensor Signal Conditioning | Thermocouple Amplification |
|---|---|
|
Use Scenario: Amplifying microvolt-level bridge outputs from MEMS pressure transducers in HVAC and medical devices. IC Role / Device Role / Timing Role: Precision DC amplifier with auto-zero correction, rejecting thermal EMF drift and 50/60 Hz line noise. Use Value: 0.04 μV/°C drift and 1.2 μVp-p (0.1–10 Hz) noise enable sub-0.1% full-scale error over temperature without calibration. |
Use Scenario: Cold-junction compensation and linearization of Type K/J thermocouples in industrial ovens and battery packs. IC Role / Device Role / Timing Role: Low-drift instrumentation amplifier front-end, referenced to precision RTD or thermistor. Use Value: 9 μV max offset ensures ≤0.25°C absolute error at 1000°C (Type K), eliminating need for frequent zero-point recalibration. |
| Precision Current Sensing | Medical Instrumentation |
|
Use Scenario: Shunt-based current monitoring in motor drives and power supplies with 10 mΩ to 100 mΩ sense resistors. IC Role / Device Role / Timing Role: High-common-mode rejection amplifier with rail-to-rail output driving 12-bit+ SAR ADCs. Use Value: 133 dB CMRR rejects >100 V common-mode voltages; 10 mV output low enables accurate 0 A detection at 5 V supply. |
Use Scenario: Front-end amplification for ECG, EEG, and impedance plethysmography in portable diagnostic equipment. IC Role / Device Role / Timing Role: Ultra-low-noise, low-bias amplifier for biopotential acquisition with >100 dB SNR. Use Value: 40 pA max input bias avoids electrode polarization errors; 1.2 μVp-p noise preserves microvolt-level cardiac signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8628ARZ | 2.7–5 V supply only; 1 μV typ offset; 0.005 μV/°C drift; lower bandwidth (2.5 MHz) | Optimized for battery-powered, low-voltage precision systems - not rated for 16 V operation or extended temperature. | Select AD8628ARZ when supply is ≤5 V and ultra-low drift dominates over wide supply flexibility. |
| LTC2057HS8#PBF | 5–12 V supply; 0.5 μV typ offset; 0.015 μV/°C drift; higher quiescent current (1.8 mA) | Includes shutdown mode and enhanced EMI rejection; not qualified to −40°C to +125°C industrial grade. | Select LTC2057HS8#PBF when EMI robustness and shutdown capability are required in 12 V systems. |
Compared with AD8628ARZ and LTC2057HS8#PBF, AD8638ARZ uniquely supports 16 V operation and full −40°C to +125°C qualification while maintaining sub-10 μV offset - making it the only option for high-voltage industrial sensor nodes requiring long-term zero-drift stability.
Availability
AD8638ARZ is available at Aetrix Electronics and suitable for pressure sensor signal conditioning, thermocouple amplification, and precision current sensing requiring stable component supply across automotive, industrial, and medical production programs.
Supply support for AD8638ARZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD8638ARZ belongs to Analog Devices' auto-zero op amp family designed specifically for ultra-precision DC measurement applications demanding near-zero drift, low 1/f noise, and rail-to-rail output in harsh thermal environments.
FAQ
What is the maximum supply voltage rating for AD8638ARZ?
The AD8638ARZ has an absolute maximum supply voltage rating of 16 V, with recommended operation from 5 V to 16 V single-supply or ±2.5 V to ±8 V dual-supply. Exceeding 16 V risks permanent damage per Absolute Maximum Ratings Table 4. The AD8638ARZ maintains full specification compliance across this entire range, including 1.5 MHz gain bandwidth and 15.94 V output high at 16 V supply.
Does AD8638ARZ require external capacitors for stability?
No, AD8638ARZ is internally compensated and stable with capacitive loads up to 20 pF without external components. Its patented auto-zero architecture eliminates the need for external nulling capacitors. The AD8638ARZ remains stable driving 10 kΩ || 20 pF loads - verified in Figure 17 and Table 2/3 - reducing design complexity and board space.
Is AD8638ARZ suitable for thermocouple amplification at 125°C ambient?
Yes, AD8638ARZ is fully specified from −40°C to +125°C and qualified for extended industrial temperature operation. At +125°C, its offset voltage remains ≤23 μV and drift ≤0.06 μV/°C (non-SOT-23 packages), ensuring reliable cold-junction compensation accuracy in furnace controllers and battery thermal management systems using the AD8638ARZ.
How does AD8638ARZ eliminate 1/f noise?
AD8638ARZ eliminates 1/f noise via its dual-stage auto-zero + chopping ping-pong architecture. The internal circuitry continuously measures and cancels low-frequency offset and 1/f components at ~15 kHz, resulting in 1.2 μVp-p (0.1–10 Hz) noise - effectively removing 1/f contribution. This is confirmed in Theory of Operation (Page 14) and Figure 42/45 of the AD8638ARZ datasheet Rev. F.
What is the output voltage swing specification for AD8638ARZ at 5 V supply?
At 5 V supply and 10 kΩ load, AD8638ARZ delivers VOH = 4.97 V (min) and VOL = 10 mV (max), achieving true rail-to-rail output swing. Under heavier 2 kΩ load, swing degrades to VOH = 4.90 V and VOL = 32 mV - values confirmed in Table 2 Electrical Characteristics. This enables >99% utilization of 5 V ADC reference range when using the AD8638ARZ.
AD8638ARZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Zero-Drift
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 2V/µs
- Gain Bandwidth Product:
- 1.5 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 1 pA
- Voltage - Input Offset:
- 3 µV
- Current - Supply:
- 1.25mA
- Current - Output / Channel:
- 37 mA
- Voltage - Supply Span (Min):
- 5 V
- Voltage - Supply Span (Max):
- 16 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
AD8638ARZ FAQ
1.How can I place an order for AD8638ARZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD8638ARZ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD8638ARZ reliable?
The price and inventory of AD8638ARZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD8638ARZ is usually 5 days.
3.What payment methods are accepted for AD8638ARZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD8638ARZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD8638ARZ?
AD8638ARZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD8638ARZ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD8638ARZ?
For technical support, including AD8638ARZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD8638ARZ requirements.
6.How does Aetrix verify that AD8638ARZ is sourced from the original manufacturer or authorized distributors?
All AD8638ARZ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD8638ARZ meets industry standards.
7.What is the process for return or replacement of AD8638ARZ?
All AD8638ARZ units undergo pre-shipment inspection (PSI). If there is an issue with AD8638ARZ, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD8638ARZ part is unused and in its original packaging.
Return procedure for AD8638ARZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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