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Analog Devices Inc./Maxim Integrated ICL7650CPA+
- Part No.:
- ICL7650CPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
ICL7650CPA+.pdf
- Description:
- IC OPAMP ZER-DRIFT 1CIRC 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,957
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Product details
Overview
ICL7650CPA+ from Maxim Integrated is an 8-pin plastic DIP chopper-stabilized operational amplifier designed for ultra-low-offset, low-drift DC signal conditioning in precision instrumentation. It delivers 1 µV max input offset voltage, 0.01 µV/°C temperature coefficient, 10 pA input bias current, and 2.0 MHz unity-gain bandwidth - enabling stable thermocouple amplification and strain gauge readout at room temperature and beyond.
For engineers reviewing the ICL7650CPA+ datasheet, ICL7650CPA+ pinout, ICL7650CPA+ application, or ICL7650CPA+ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional trade-offs.
Technical Context
The ICL7650CPA+ implements a dual-amplifier chopper architecture: a main amplifier continuously connected from input to output, and a nulling amplifier that alternately self-nulls and corrects the main amplifier's offset under control of an internal 200 Hz oscillator. This closed-loop nulling operates across full supply (±3 V to ±8 V) and common-mode ranges (–5.2 V to +3.0 V), independent of output level.
Its monolithic CMOS design integrates high-impedance MOSFET back-gate nulling connections, external capacitor-based null storage (CEXTA/CEXTB), and - uniquely in the ICL7650 variant - an output clamp circuit (Pin 5) that reduces overload recovery time by limiting uncontrolled differential input during saturation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Offset Voltage | 1 µV max (typical 0.7 µV) - enables sub-10 µV system-level DC error in precision sensor front-ends without trimming. |
| Offset Tempco | 0.01 µV/°C max - ensures <1 µV drift over 0°C to +70°C commercial range, critical for unattended industrial logging. |
| Input Bias Current | 10 pA max - supports direct interfacing to high-impedance sources like thermistors (>100 MΩ) with minimal voltage error. |
| CMRR / PSRR | 120 dB min - rejects >100,000:1 common-mode or supply noise, essential in noisy industrial power environments. |
| Unity-Gain BW | 2.0 MHz - allows stable closed-loop operation up to ~100 kHz with 10 kΩ load, supporting fast-settling DC-coupled acquisition. |
| Supply Current | 2.0 mA max - enables low-power battery-operated precision instruments without thermal drift penalties. |
| Output Swing | ±4.7 V into 10 kΩ (±5 V supplies) - delivers full-rail usable dynamic range for 16-bit ADC drivers. |
Pinout & Package
ICL7650CPA+ is supplied in an 8-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; leads are tin-lead plated per JEDEC MS-001.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CEXTA | Null storage capacitor terminal A - connects to 0.1 µF low-leakage film cap (e.g., polypropylene) tied to V− for stable offset correction. |
| 2 | −INPUT | Inverting input - high-impedance CMOS node; requires guarding to prevent leakage-induced offset drift. |
| 3 | +INPUT | Non-inverting input - same guarding requirements as Pin 2; differential input voltage range extends to ±5.2 V. |
| 4 | V− | Negative supply rail - serves as reference for CEXTA/CEXTB capacitors and CLAMP circuit; must be low-impedance. |
| 5 | CLAMP | Output clamp control - ties to summing junction to limit saturation charge buildup and reduce recovery time from overload. |
| 6 | OUTPUT | Main amplifier output - capable of ±4.7 V swing into 10 kΩ; includes internal clamp diode path when Pin 5 is active. |
| 7 | V+ | Positive supply rail - accepts +3 V to +8 V; internal regulator derives bias for chopper clock and nulling logic. |
| 8 | CEXTB | Null storage capacitor terminal B - second capacitor node completing the chopper nulling loop; matched to CEXTA. |
Key Features
| Feature | Design Value |
|---|---|
| Chopper stabilization | Continuous auto-nulling eliminates manual trim and holds offset ≤1 µV across 0°C to +70°C without drift compensation. |
| Output clamp circuit | Reduces overload recovery time by >50% vs. ICL7653 - prevents charge accumulation on null capacitors during saturation. |
| No offset trimming required | Removes potentiometer, board space, and calibration labor - simplifies production test and improves long-term reliability. |
| High CMRR/PSRR | 120 dB minimum ensures stable gain in presence of 60 Hz line noise or switching supply ripple without additional filtering. |
| Low input bias current | 10 pA max enables direct connection to thermistors, pH electrodes, or piezoresistive sensors without guard-driven buffers. |
Applications
| Thermocouple Amplifier | Strain Gauge Signal Chain |
|---|---|
|
Use Scenario: Amplifying µV-level Seebeck voltages from Type K thermocouples in industrial furnace controllers. IC Role / Device Role / Timing Role: Primary DC-coupled instrumentation amplifier stage, providing offset stability and common-mode rejection before ADC digitization. Use Value: 1 µV offset + 0.01 µV/°C drift ensures <5 µV total error over 50°C span - meeting Class 1 thermocouple accuracy standards. |
Use Scenario: Reading Wheatstone bridge outputs from metal foil strain gauges in load cells used in weigh scales. IC Role / Device Role / Timing Role: Low-noise, low-drift difference amplifier with guarded inputs to reject bridge excitation noise and thermal EMFs. Use Value: 10 pA bias current avoids loading 350 Ω bridge arms; 120 dB CMRR suppresses 10 mV common-mode excitation ripple. |
| Medical ECG Front-End | Calibration Reference Buffer |
|
Use Scenario: First-stage amplification of microvolt-level biopotentials in portable ECG monitors with dry electrodes. IC Role / Device Role / Timing Role: Ultra-low-input-current, high-CMRR buffer isolating electrode interface from downstream filters and ADC drivers. Use Value: 10 pA bias current prevents polarization voltage buildup on skin-electrode interface; 2 MHz GBW supports fast transient response to R-wave spikes. |
Use Scenario: Buffering precision voltage references (e.g., LTZ1000) in automated test equipment calibration modules. IC Role / Device Role / Timing Role: Zero-drift unity-gain follower maintaining reference integrity against load variations and thermal gradients. Use Value: 1 µV offset and <1 µV drift over 8 hours ensure reference stability within 0.5 ppm - sufficient for 24-bit DAC calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar chopper-stabilized op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ICL7653CPA+ | No CLAMP pin (Pin 5); lower 10 Hz–10 kHz noise density (1.5 µVp-p vs. 2.0 µVp-p); identical offset and drift specs. | Better AC common-mode rejection; preferred where overload recovery is not critical and lowest noise is prioritized. | Select ICL7653CPA+ if clamp functionality is unnecessary and system noise floor dominates performance. |
| LTC2057HMS8#PBF | Zero-drift architecture with higher 3.5 MHz GBW, 1.5 nV/√Hz voltage noise, and rail-to-rail output - but 25 pA bias current. | Superior bandwidth and noise for dynamic sensor signals; less suitable for ultra-high-Z sources like glass pH electrodes. | Choose LTC2057HMS8#PBF when faster settling (<10 µs to 16-bit) and lower broadband noise outweigh ultra-low bias current needs. |
Compared with ICL7650CPA+, ICL7653CPA+ removes clamp functionality for lower noise, while LTC2057HMS8#PBF trades ultra-low bias current for higher speed and noise performance - making each optimal for distinct precision analog signal chains.
Availability
ICL7650CPA+ is available at Aetrix Electronics and suitable for thermocouple amplification, strain gauge readout, medical biopotential sensing, and precision reference buffering requiring stable component supply across industrial, test & measurement, and medical OEM programs.
Supply support for ICL7650CPA+ 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
Maxim Integrated (now part of Analog Devices) designs high-performance analog and mixed-signal ICs for precision, power, and interface applications - with emphasis on reliability and integration for demanding industrial and medical systems.
The ICL7650CPA+ belongs to Maxim's chopper-stabilized op amp family, engineered specifically for DC-critical applications where offset, drift, and bias current dominate system error budgets - such as sensor signal conditioning and metrology-grade instrumentation.
FAQ
What is the maximum operating supply voltage for the ICL7650CPA+?
The ICL7650CPA+ supports a total supply voltage (V+ to V−) of up to 18 V, with recommended operation between ±3 V and ±8 V. Absolute maximum ratings specify ±9 V per rail; exceeding ±8 V increases clock ripple and may degrade long-term offset stability due to increased capacitor leakage. The ICL7650CPA+'s internal regulation maintains consistent chopper frequency and nulling performance across this range.
Does the ICL7650CPA+ require external capacitors, and what type is recommended?
Yes, the ICL7650CPA+ requires two external nulling capacitors (CEXTA and CEXTB) connected to Pins 1 and 8. For the internal 200 Hz clock, 0.1 µF film capacitors (e.g., polypropylene) are recommended to minimize dielectric absorption and achieve 1 µV settling in 100 ms. Ceramic capacitors increase settling time to several seconds and raise clock ripple; mylar types offer a cost-effective compromise with acceptable leakage.
How does the CLAMP pin (Pin 5) improve overload recovery in the ICL7650CPA+?
The CLAMP pin (Pin 5) in the ICL7650CPA+ connects to the inverting input summing junction, creating a controlled current path that limits differential input voltage before the output saturates. This prevents uncontrolled charge buildup on the internal nulling capacitors, reducing typical overload recovery time from >10 ms to <1 ms. The ICL7650CPA+'s clamp circuit is absent in the ICL7653CPA+, making it the distinguishing feature for fast-recovery applications.
Can the ICL7650CPA+ replace legacy op amps like the LM741 or OP07 without board changes?
No - the ICL7650CPA+ uses a non-standard pinout: Pins 1 and 8 are CEXTA/CEXTB (not offset null), Pin 5 is CLAMP (not NC), and no dedicated offset null pins exist. Direct replacement requires PCB modification. However, LM741/OP07 boards can be retrofitted by removing the null potentiometer and connecting 0.1 µF caps from Pins 1/8 to V−, then routing Pin 5 to the inverting input for clamping - preserving existing layout where feasible.
What is the guaranteed input offset voltage specification for the ICL7650CPA+ over temperature?
The ICL7650CPA+ guarantees a maximum input offset voltage of 1 µV at +25°C and 5 µV over the full 0°C to +70°C commercial temperature range. Its average temperature coefficient is specified at 0.01 µV/°C max, resulting in ≤0.5 µV drift across that range - verified per Maxim's Electrical Characteristics table for ICL7650 (not the B-grade). This performance is maintained without trimming or external calibration.
ICL7650CPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- Chopper (Zero-Drift)
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 2.5V/µs
- Gain Bandwidth Product:
- 2 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 1.5 pA
- Voltage - Input Offset:
- 700 µV
- Current - Supply:
- 1.2mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 16 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
ICL7650CPA+ FAQ
1.How can I place an order for ICL7650CPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for ICL7650CPA+ 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 ICL7650CPA+ reliable?
The price and inventory of ICL7650CPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ICL7650CPA+ is usually 5 days.
3.What payment methods are accepted for ICL7650CPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ICL7650CPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ICL7650CPA+?
ICL7650CPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ICL7650CPA+ 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 ICL7650CPA+?
For technical support, including ICL7650CPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ICL7650CPA+ requirements.
6.How does Aetrix verify that ICL7650CPA+ is sourced from the original manufacturer or authorized distributors?
All ICL7650CPA+ 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 ICL7650CPA+ meets industry standards.
7.What is the process for return or replacement of ICL7650CPA+?
All ICL7650CPA+ units undergo pre-shipment inspection (PSI). If there is an issue with ICL7650CPA+, 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 ICL7650CPA+ part is unused and in its original packaging.
Return procedure for ICL7650CPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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