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Analog Devices Inc. ADA4638-1ARZ
- Part No.:
- ADA4638-1ARZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ADA4638-1ARZ.pdf
- Description:
- IC OPAMP ZERO-DRIFT 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,511
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Product details
Overview
ADA4638-1ARZ from Analog Devices is a 30 V, zero-drift, rail-to-rail output precision operational amplifier optimized for ultra-low offset and drift in high-gain DC-coupled sensor interfaces. It delivers 4 μV max offset voltage, 0.05 μV/°C max drift (SOIC), 130 dB min CMRR, 120 dB min PSRR, and operates from ±2.25 V to ±15 V or 4.5 V to 30 V single supply - enabling direct interfacing with strain gages and thermocouples in industrial weighing systems.
For engineers reviewing the ADA4638-1ARZ datasheet, ADA4638-1ARZ pinout, ADA4638-1ARZ application, or ADA4638-1ARZ equivalent, this page provides verified package mapping (SOIC-8), validated pin functions, confirmed rail-to-rail output swing under 2 kΩ load, exact offset drift vs. temperature behavior, and two field-validated alternative parts for precision instrumentation design.
Technical Context
The ADA4638-1ARZ implements a patented dual-stage auto-zeroing and chopping architecture operating at 8 kHz auto-zero and 16 kHz chop frequencies, eliminating 1/f noise while suppressing aliasing artifacts. Its input stage uses transconductance amplifiers A1/A2 with nulling amplifiers A3/A4 and storage capacitors C1–C4 to dynamically correct offset in alternating phases.
This ping-pong topology ensures continuous signal path integrity with no output phase reversal, supports input common-mode range extending to the negative rail, and maintains 1.5 V/μs slew rate and 2.5 MHz −3 dB bandwidth (AV = +1, VS = 30 V) without sacrificing DC accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset Voltage | 4.5 μV max (25°C, SOIC); enables sub-10 ppm error in 1 V full-scale 24-bit ADC front-ends |
| Offset Drift | 0.05 μV/°C max (−40°C to +125°C, SOIC); guarantees <0.75 μV total drift over industrial temp range |
| CMRR | 130 dB min (−40°C to +125°C); rejects >3.16 MV/V common-mode interference in bridge sensor circuits |
| PSRR | 120 dB min (−40°C to +125°C); suppresses supply ripple to <10 nV/V at output |
| Rail-to-Rail Output | VOL = 60 mV max, VOH = 29.92 V min (RL = 10 kΩ, VS = 30 V); delivers >99.8% supply utilization for maximum SNR |
| Supply Current | 0.95 mA max per amplifier; allows low-power operation in battery-backed instrumentation |
| Input Bias Current | 90 pA max (25°C); minimizes voltage error across >100 MΩ sensor source impedances |
Pinout & Package
ADA4638-1ARZ is supplied in an 8-lead SOIC package (body width 3.9 mm, JEDEC MS-012). The exposed pad is not present in SOIC; pin 1 is NC and must remain unconnected. Pin 5 is NC and must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | No Connect | Internally unused; must be left floating - no PCB trace or thermal pad connection |
| 2 | Inverting Input (−IN) | Differential input node; accepts signals referenced to V−; supports rail-to-rail common-mode range |
| 3 | Noninverting Input (+IN) | Differential input node; accepts signals down to V−; ESD-protected with internal diodes to rails |
| 4 | Negative Supply (V−) | Power ground reference for dual supply; connects to system GND or negative rail in single-supply configs |
| 5 | No Connect | Internally unused; must be left floating - no routing or decoupling |
| 6 | Output (OUT) | Class AB rail-to-rail output driver; capable of sourcing/sinking ±38 mA; requires local 100 nF ceramic decoupling |
| 7 | Positive Supply (V+) | Power rail input; accepts 4.5 V to 30 V; requires 100 nF + 10 μF parallel decoupling |
| 8 | No Connect | Internally unused; must be left floating - no thermal or electrical connection |
Key Features
| Feature | Design Value |
|---|---|
| Zero-drift architecture | Patented auto-zero + chopping eliminates 1/f noise and reduces long-term drift to <0.05 μV/°C |
| Rail-to-rail output | Swings within 60 mV of V− and 80 mV of V+ at 2 kΩ load, maximizing dynamic range in 24-bit data acquisition |
| No output phase reversal | Guaranteed under all input overdrive and common-mode conditions - critical for closed-loop stability |
| Extended temperature range | Specified from −40°C to +125°C; validated offset performance across full range in SOIC packaging |
| Low input bias current | 90 pA max enables accurate amplification of high-impedance sources like piezoresistive sensors |
Applications
| Electronic Weigh Scale | Pressure Sensor Interface |
|---|---|
Use Scenario: Amplifying mV-level output from 350 Ω Wheatstone bridge load cells in factory-floor weighing platforms. IC Role / Device Role / Timing Role: Primary signal-conditioning amplifier with gain ≥1000, rejecting bridge excitation ripple and thermal EMF drift. Use Value: 4.5 μV offset and 0.05 μV/°C drift ensure ≤0.005% FS error over −10°C to +50°C ambient - meeting OIML R76 Class III requirements. | Use Scenario: Conditioning output from silicon piezoresistive pressure transducers in HVAC differential pressure monitoring. IC Role / Device Role / Timing Role: Low-noise, DC-stable gain stage driving SAR ADC inputs with 16+ ENOB at 100 kSPS. Use Value: 1.2 μVp-p (0.1–10 Hz) noise and rail-to-rail output enable full-scale utilization of 5 V ADC reference, improving resolution by 1.5 bits. |
| Thermocouple Amplifier | Medical Instrumentation |
Use Scenario: Cold-junction compensation and linearization of Type K thermocouple outputs in industrial ovens. IC Role / Device Role / Timing Role: Precision instrumentation amplifier front-end with programmable gain and low thermal EMF PCB layout. Use Value: Input bias current ≤90 pA prevents self-heating errors in high-resistance thermocouple leads; CMRR ≥130 dB rejects furnace EMI. | Use Scenario: Biopotential signal conditioning in portable ECG monitors requiring FDA 510(k) compliance. IC Role / Device Role / Timing Role: First-stage amplifier for electrode-skin interface with DC-coupled baseline stability. Use Value: No 1/f noise and <0.05 μV/°C drift eliminate baseline wander over 8-hour clinical sessions; PSRR ≥120 dB suppresses switching regulator noise. |
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 | Lower supply voltage (5.5 V max), 5 μV offset, 0.02 μV/°C drift; no 30 V rating | Optimized for low-voltage, battery-powered portable instruments - not suitable for 24 V industrial sensors | Select AD8628ARZ only when supply is ≤5.5 V and ultra-low drift dominates over voltage range |
| ADA4528-1ARMZ | 2.5 μV offset, 0.015 μV/°C drift, but limited to 5.5 V max supply; LFCSP-only packaging | Better drift spec but incompatible with 24 V bridge excitation; requires re-layout for 8-lead MSOP | Choose ADA4528-1ARMZ only for ultra-high-precision, low-voltage medical designs where 30 V operation is unnecessary |
Compared with AD8628ARZ and ADA4528-1ARMZ, the ADA4638-1ARZ uniquely supports 30 V operation while maintaining sub-5 μV offset and <0.06 μV/°C drift - making it the sole option for high-voltage precision sensing without external level-shifting or supply regulation.
Availability
ADA4638-1ARZ is available at Aetrix Electronics and suitable for electronic weigh scale, pressure sensor interface, and thermocouple amplifier applications requiring stable component supply across extended temperature and voltage ranges.
Supply support for ADA4638-1ARZ 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 ADA4638-1ARZ belongs to Analog Devices' zero-drift precision op amp product line, engineered specifically for DC-accurate amplification of microvolt-level sensor outputs in harsh industrial and medical environments.
FAQ
What is the maximum supply voltage rating for the ADA4638-1ARZ?
The ADA4638-1ARZ has an absolute maximum supply voltage rating of 33 V, with guaranteed operation from 4.5 V to 30 V single supply or ±2.25 V to ±15 V dual supplies. Operation beyond 30 V is not characterized and may compromise long-term reliability or parametric performance per the Rev. 0 datasheet.
Does the ADA4638-1ARZ require external compensation for unity-gain stability?
No, the ADA4638-1ARZ is internally compensated and unity-gain stable. Its phase margin is 69° at 1 MHz with 20 pF load and AV = +1, and it achieves 2.5 MHz −3 dB bandwidth under those conditions - no external compensation components are needed for standard configurations.
How does the ADA4638-1ARZ handle input overvoltage conditions?
The ADA4638-1ARZ includes ESD protection diodes from each input to V+ and V−. If either input exceeds the supply rails, these diodes become forward-biased and conduct. To prevent damage, external series resistors must limit input current to ≤10 mA - a 2.4 kΩ resistor is recommended for 24 V systems.
Can the ADA4638-1ARZ drive heavy capacitive loads directly?
The ADA4638-1ARZ is not optimized for direct heavy capacitive loading. With 100 pF load, overshoot remains <10% at AV = +1, but larger capacitances (>500 pF) require isolation resistance or feedback capacitor compensation. For 1 nF loads, a 10 Ω series resistor at the output is recommended to maintain stability.
Is the ADA4638-1ARZ pin-compatible with other zero-drift op amps in SOIC-8 packages?
No - the ADA4638-1ARZ has two no-connect pins (1 and 5) and nonstandard pinout versus industry-standard SOIC-8 op amps (e.g., AD8628ARZ uses pin 1 for shutdown). Direct replacement requires PCB redesign; pin compatibility is not claimed in the datasheet or Analog Devices documentation.
ADA4638-1ARZ 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:
- 1.5V/µs
- Gain Bandwidth Product:
- 1.5 MHz
- -3db Bandwidth:
- 2.5 MHz
- Current - Input Bias:
- 45 pA
- Voltage - Input Offset:
- 0.5 µV
- Current - Supply:
- 850µA
- Current - Output / Channel:
- 38 mA
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 30 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ADA4638-1ARZ FAQ
1.How can I place an order for ADA4638-1ARZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ADA4638-1ARZ 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 ADA4638-1ARZ reliable?
The price and inventory of ADA4638-1ARZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADA4638-1ARZ is usually 5 days.
3.What payment methods are accepted for ADA4638-1ARZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADA4638-1ARZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADA4638-1ARZ?
ADA4638-1ARZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADA4638-1ARZ 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 ADA4638-1ARZ?
For technical support, including ADA4638-1ARZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADA4638-1ARZ requirements.
6.How does Aetrix verify that ADA4638-1ARZ is sourced from the original manufacturer or authorized distributors?
All ADA4638-1ARZ 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 ADA4638-1ARZ meets industry standards.
7.What is the process for return or replacement of ADA4638-1ARZ?
All ADA4638-1ARZ units undergo pre-shipment inspection (PSI). If there is an issue with ADA4638-1ARZ, 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 ADA4638-1ARZ part is unused and in its original packaging.
Return procedure for ADA4638-1ARZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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