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Analog Devices Inc. ADA4638-1ACPZ-R7
- Part No.:
- ADA4638-1ACPZ-R7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-WFDFN Exposed Pad, CSP
- Datasheet:
-
ADA4638-1ACPZ-R7.pdf
- Description:
- IC OPAMP ZERO-DRIFT 1CIRC 8LFCSP
- Quantity:
- Payment:
- Shipping:
Inventory:151
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Product details
Overview
ADA4638-1ACPZ-R7 from Analog Devices is a single-channel, high-voltage zero-drift operational amplifier with rail-to-rail output, 4.5 μV max offset voltage, 0.05 μV/°C max drift (LFCSP), and 130 dB min CMRR. It operates from 4.5 V to 30 V single supply or ±2.25 V to ±15 V dual supply, consuming ≤0.95 mA, and targets precision DC-coupled sensor signal conditioning in harsh industrial environments.
For engineers reviewing the ADA4638-1ACPZ-R7 datasheet, ADA4638-1ACPZ-R7 pinout, ADA4638-1ACPZ-R7 application, or ADA4638-1ACPZ-R7 equivalent, this page delivers verified package mapping (8-lead LFCSP), validated rail-to-rail output swing under load, confirmed zero-drift architecture with auto-zero + chopping, and real-world design meaning for thermocouple, strain gage, and medical instrumentation use cases.
Technical Context
The ADA4638-1ACPZ-R7 implements a patented ping-pong auto-zeroing and chopping architecture with 8 kHz auto-zero and 16 kHz chopping frequencies, eliminating 1/f noise and enabling ultralow drift over −40°C to +125°C. 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.
It features input common-mode range extending to the negative rail, no output phase reversal, and ESD protection diodes on both inputs referenced to supply rails. The exposed thermal pad must be connected to V− per datasheet Note 2, and the four NC pins are electrically isolated with no internal connection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Offset Voltage | 4.5 μV max at 25°C (SOIC); enables ≤0.001% gain error in 100× strain gage bridges at room temperature |
| Offset Drift | 0.05 μV/°C max (−40°C to +125°C, LFCSP); ensures <0.6 μV total drift across full industrial temp range |
| Supply Range | 4.5 V to 30 V single or ±2.25 V to ±15 V dual; supports direct interface to 24 V industrial sensors without regulation |
| Rail-to-Rail Output | VOL = 10 mV, VOH = 29.85 V @ 30 V supply, RL = 10 kΩ; delivers >99.9% of full-scale dynamic range for 24-bit ADCs |
| CMRR / PSRR | 130 dB min CMRR, 120 dB min PSRR; rejects >3.16 million:1 common-mode or supply ripple interference |
| Input Noise | 1.2 μV p-p (0.1 Hz–10 Hz); preserves resolution in sub-μV thermocouple outputs without external filtering |
| Gain-Bandwidth | 1.5 MHz GBP; supports stable 100× closed-loop gain up to 15 kHz for fast pressure sensor response |
Pinout & Package
ADA4638-1ACPZ-R7 is packaged in an 8-lead LFCSP (3 mm × 3 mm) with exposed thermal pad. Pin 1 is NC (no connect), Pin 2 is –IN, Pin 3 is +IN, Pin 4 is V−, Pin 5 is NC, Pin 6 is OUT, Pin 7 is V+, Pin 8 is NC. The exposed pad must be soldered to V− for thermal and electrical performance per datasheet Note 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1, Pin 5, Pin 8 | No Connect (NC) | Electrically isolated; must remain unconnected per datasheet Note 1 |
| Pin 2 | Inverting Input (–IN) | Differential input node; accepts signals down to V− rail with full CMRR |
| Pin 3 | Noninverting Input (+IN) | Differential input node; supports rail-to-rail common-mode input range |
| Pin 4 | Negative Supply (V−) | Power return; exposed pad must be connected to this pin for thermal management |
| Pin 6 | Output (OUT) | Class AB output stage; drives 10 kΩ loads to within 10 mV of rails at 30 V supply |
| Pin 7 | Positive Supply (V+) | High-voltage supply input; rated for 33 V absolute max per datasheet Table 5 |
Key Features
| Feature | Design Value |
|---|---|
| Zero-drift architecture | Patented auto-zero + chopping eliminates 1/f noise and guarantees <0.05 μV/°C drift over full temperature range |
| Rail-to-rail output | Delivers 29.85 V high and 10 mV low output swing at 30 V supply, maximizing SNR into 24-bit ADCs |
| High PSRR/CMRR | 120 dB PSRR and 130 dB CMRR suppress power supply ripple and sensor common-mode interference |
| Low input bias current | 45 pA typical IB enables high-impedance sensor interfaces (e.g., pH electrodes, piezoresistive elements) without significant error |
| Extended temperature range | Specified from −40°C to +125°C; qualified for automotive under-hood and industrial motor control applications |
Applications
| Electronic Weigh Scale | Thermocouple Amplifier |
|---|---|
Use Scenario: High-resolution load cell measurement in factory floor scales with ambient temperature swings from 0°C to 50°C. IC Role / Device Role / Timing Role: Precision front-end amplifier for Wheatstone bridge output, rejecting common-mode noise from 24 V supply rails. Use Value: 4.5 μV offset and 0.05 μV/°C drift ensure ≤1 LSB error over full scale in 20-bit systems without recalibration. |
Use Scenario: Cold-junction compensation and microvolt-level thermocouple signal amplification in medical patient monitors. IC Role / Device Role / Timing Role: Low-noise, zero-drift gain stage with rail-to-rail output driving SAR ADC reference buffer. Use Value: 1.2 μV p-p (0.1–10 Hz) noise and no 1/f component preserve sub-0.1°C temperature resolution. |
| Strain Gage Amplifier | Medical Instrumentation |
Use Scenario: Fatigue testing machine measuring microstrain on aerospace components under vibration and thermal cycling. IC Role / Device Role / Timing Role: Instrumentation-grade signal conditioner with matched input impedance and high open-loop gain (140 dB). Use Value: 130 dB CMRR rejects EMI from nearby motors; 30 V supply headroom accommodates high-excitation bridge voltages. |
Use Scenario: EEG/ECG front-end analog signal chain requiring ultra-low drift and biopotential-level noise immunity. IC Role / Device Role / Timing Role: DC-coupled differential amplifier with input-referred noise below 70 nV/√Hz at 1 kHz. Use Value: Zero-drift operation prevents baseline wander during multi-hour recordings; rail-to-rail output maximizes dynamic range. |
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 V max), 5 μV offset, 0.02 μV/°C drift, SOIC-8 only | Optimized for battery-powered portable instruments; not rated for 30 V operation | Select AD8628ARZ when supply is ≤5 V and ultra-low drift dominates over voltage range |
| ADA4528-1ARMZ | 2.5 μV offset, 0.015 μV/°C drift, 16 V max supply, MSOP-8 package | Better drift spec but limited to 16 V; lacks 30 V capability for industrial 24 V systems | Choose ADA4528-1ARMZ for highest DC accuracy in ≤16 V medical or test equipment |
Compared with AD8628ARZ and ADA4528-1ARMZ, the ADA4638-1ACPZ-R7 uniquely combines 30 V operation, 0.05 μV/°C drift, and rail-to-rail output-making it the only option for high-voltage, high-accuracy sensor conditioning where supply headroom and thermal stability are co-constrained.
Availability
ADA4638-1ACPZ-R7 is available at Aetrix Electronics and suitable for electronic weigh scale, thermocouple amplifier, and medical instrumentation applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ADA4638-1ACPZ-R7 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 ADA4638-1ACPZ-R7 belongs to Analog Devices' zero-drift op amp portfolio designed specifically for ultra-precision DC and low-frequency signal conditioning in industrial, medical, and test equipment where offset, drift, and noise directly limit measurement resolution.
FAQ
What is the maximum supply voltage rating for the ADA4638-1ACPZ-R7?
The ADA4638-1ACPZ-R7 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. Exceeding 33 V risks permanent damage per datasheet Table 5 Absolute Maximum Ratings.
Does the ADA4638-1ACPZ-R7 require external compensation for unity-gain stability?
No, the ADA4638-1ACPZ-R7 is internally compensated and stable at unity gain (AV = +1). Datasheet Figure 23 and Figure 26 confirm ≥64° phase margin across operating conditions, and no external compensation components are needed for standard configurations.
How does the exposed thermal pad on the ADA4638-1ACPZ-R7 package function?
The exposed pad on the ADA4638-1ACPZ-R7 LFCSP package must be soldered to the V− net per datasheet Note 2. This connection provides critical thermal dissipation (θJC = 12°C/W) and reduces junction temperature rise by up to 40°C versus floating-pad layouts, ensuring reliability at full 30 V supply.
Can the ADA4638-1ACPZ-R7 drive capacitive loads directly?
The ADA4638-1ACPZ-R7 can drive up to 100 pF capacitive loads while maintaining stability, as shown in Figures 39 and 42 (overshoot <10%). For larger loads, an isolation resistor (e.g., 10–100 Ω) between OUT and the capacitor is recommended to prevent peaking or oscillation.
What is the input voltage range specification for the ADA4638-1ACPZ-R7 at 30 V supply?
At VS = 30 V, the ADA4638-1ACPZ-R7 input common-mode voltage range extends from 0 V to 27 V (VSY/2 = 15 V nominal, but full range is rail-to-rail minus 3 V headroom). This allows direct interfacing with sensors referenced to ground or mid-supply without level-shifting circuitry.
ADA4638-1ACPZ-R7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad, CSP
- Packaging:
- Tape & Reel (TR)
- 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-LFCSP-WD (3x3)
ADA4638-1ACPZ-R7 FAQ
1.How can I place an order for ADA4638-1ACPZ-R7 through Aetrix?
Please submit a Request for Quotation (RFQ) for ADA4638-1ACPZ-R7 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 ADA4638-1ACPZ-R7 reliable?
The price and inventory of ADA4638-1ACPZ-R7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADA4638-1ACPZ-R7 is usually 5 days.
3.What payment methods are accepted for ADA4638-1ACPZ-R7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADA4638-1ACPZ-R7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADA4638-1ACPZ-R7?
ADA4638-1ACPZ-R7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADA4638-1ACPZ-R7 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 ADA4638-1ACPZ-R7?
For technical support, including ADA4638-1ACPZ-R7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADA4638-1ACPZ-R7 requirements.
6.How does Aetrix verify that ADA4638-1ACPZ-R7 is sourced from the original manufacturer or authorized distributors?
All ADA4638-1ACPZ-R7 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 ADA4638-1ACPZ-R7 meets industry standards.
7.What is the process for return or replacement of ADA4638-1ACPZ-R7?
All ADA4638-1ACPZ-R7 units undergo pre-shipment inspection (PSI). If there is an issue with ADA4638-1ACPZ-R7, 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 ADA4638-1ACPZ-R7 part is unused and in its original packaging.
Return procedure for ADA4638-1ACPZ-R7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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