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Analog Devices Inc./Maxim Integrated ICL7631BCPE+
- Part No.:
- ICL7631BCPE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
ICL7631BCPE+.pdf
- Description:
- IC CMOS 3 CIRCUIT 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,444
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Product details
Overview
ICL7631BCPE+ from Maxim Integrated is a triple monolithic CMOS operational amplifier optimized for ultra-low input bias current (1 pA typical), programmable quiescent current (10 µA / 100 µA / 1 mA per amplifier), and wide supply range (±1 V to ±8 V or 2 V to 16 V single supply). It features 16-pin plastic DIP packaging, 10¹² Ω input impedance, and rail-to-rail output swing within millivolts of supply rails - ideal for picoammeter front-ends and long-time-constant integrators in battery-powered instrumentation.
For engineers reviewing the ICL7631BCPE+ datasheet, ICL7631BCPE+ pinout, ICL7631BCPE+ application, or ICL7631BCPE+ equivalent, key selection criteria include confirmed 1 pA bias current at +25°C, programmable IQ configuration via dedicated IOC pins, guaranteed operation across 0°C to +70°C, and compatibility with high-impedance pH meter and photodiode amplifier topologies requiring sub-picoampere leakage control.
Technical Context
The ICL7631BCPE+ implements a pin-selectable quiescent current architecture where each amplifier's IQ is set independently via dedicated IOC pins (pins 2, 6, and 12), enabling dynamic trade-offs between bandwidth (0.044–1.4 MHz), slew rate (0.016–1.6 V/µs), and power consumption. Its CMOS input stage delivers 10¹² Ω input resistance and 0.01 pA/√Hz input noise current, supporting stable DC coupling into multi-megaohm source impedances.
Unlike fixed-IQ dual/quad variants, the triple ICL7631 supports per-amplifier IQ programming without external resistors - each IOC pin accepts voltage thresholds (V+, mid-rail, or V−) to select 10 µA, 100 µA, or 1 mA. Output stage operates in Class A for linear swing up to 1 MΩ loads, with Class AB capability for higher current drive, while maintaining rail-swing performance down to 10 kΩ loads at 1 mA IQ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Bias Current | 1 pA typical at +25°C - enables accurate measurement of currents below 100 fA in picoammeters and electrometer-grade circuits. |
| Input Impedance | 10¹² Ω - preserves signal integrity when interfacing with high-Z sources like pH electrodes and photodiodes. |
| Supply Voltage Range | ±1 V to ±8 V (dual) or 2 V to 16 V (single) - supports low-voltage portable designs and legacy industrial rails. |
| Output Voltage Swing | ±4.9 V at ±5 V supply, RL = 1 MΩ - delivers >98% rail-to-rail dynamic range for maximum signal utilization. |
| Unity-Gain Bandwidth | 0.044 MHz (IQ = 10 µA) to 1.4 MHz (IQ = 1 mA) - allows bandwidth scaling per channel based on precision vs. speed requirements. |
| Input Noise Current | 0.01 pA/√Hz at 1 kHz - minimizes current-noise-induced errors in transimpedance amplifiers. |
| Common-Mode Voltage Range | –4.0 V to +4.4 V at ±5 V supply, IQ = 10 µA - supports input signals extending beyond negative rail in single-supply configurations. |
Pinout & Package
ICL7631BCPE+ uses a 16-pin plastic DIP (Dual In-line Package) with 0.3-inch width, standard through-hole mounting, and JEDEC MS-001 compliant footprint. Pin 1 is top-left corner (notch side), with internal connections between pins 5 and 15.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUTA | Amplifier A output - drives load directly; rail-swing capable with ≥10 kΩ load at 1 mA IQ. |
| 2 | IOC SET A | Quiescent current select for Amp A - connect to V+, mid-rail, or V− to set 10 µA / 100 µA / 1 mA. |
| 3 | +INA | Inverting input for Amp A - high-impedance CMOS node; requires guard ring layout for <1 pA leakage. |
| 4 | OUTB | Amplifier B output - independent output stage; shares same IQ programming logic as OUTA. |
| 5 | N.C. (internally tied to Pin 15) | No connect - internally bonded to Pin 15; must remain unconnected on PCB. |
| 6 | IOC SET B | Quiescent current select for Amp B - identical voltage threshold logic as Pin 2. |
| 7 | –INB | Inverting input for Amp B - electrically isolated from other inputs; guard required for pA-level accuracy. |
| 8 | V+ | Positive supply rail - accepts up to +8 V (dual) or +16 V (single); decoupling capacitor recommended. |
| 9 | +INC | Non-inverting input for Amp C - third independent amplifier input; matches +INA/+INB electrical specs. |
| 10 | –INC | Inverting input for Amp C - fully differential input pair; supports unity-gain buffer or inverting gain stages. |
| 11 | IOB SET | Quiescent current select for Amp C - Pin 12 is labeled IOB SET in datasheet; Pin 11 is N.C. in ICL7631. |
| 12 | IOC SET C | Quiescent current select for Amp C - completes per-amplifier IQ control; all three IOC pins operate identically. |
| 13 | OUTC | Amplifier C output - third independent output; supports mixed-mode signal conditioning (e.g., sensor + reference + filter). |
| 14 | +INA | Non-inverting input for Amp A - forms differential pair with Pin 3; offset nulling possible via external pot. |
| 15 | N.C. (internally tied to Pin 5) | No connect - internal bond to Pin 5; no external connection permitted. |
| 16 | V− | Negative supply rail - accepts down to –8 V (dual) or GND (single); low-impedance return path critical. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable quiescent current per amplifier | Three discrete IQ settings (10 µA / 100 µA / 1 mA) selected by simple voltage level on dedicated IOC pins - eliminates external resistors and enables per-channel power optimization. |
| Ultra-low input bias current | 1 pA typical at +25°C ensures minimal error in high-impedance feedback networks, critical for integrating capacitors >1 nF and electrometer applications. |
| Rail-to-rail output swing | Swings within 20 mV of V+ and V− at light loads - maximizes dynamic range in low-voltage systems without level-shifting circuitry. |
| 10¹² Ω input resistance | Preserves signal amplitude and time constant integrity when driving from sensors with output impedances >100 MΩ (e.g., glass pH electrodes). |
| Independent amplifier channels | Three fully isolated op-amps share supply rails but have separate inputs, outputs, and IQ controls - enables multi-function analog signal chains in compact layouts. |
Applications
| pH Meter Front-End | Photodiode Transimpedance Amplifier |
|---|---|
|
Use Scenario: Measuring hydrogen ion concentration in aqueous solutions using glass electrode with >1 GΩ output impedance. IC Role / Device Role / Timing Role: Primary DC-coupled amplifier conditioning ultra-low-current electrode output; configured at 10 µA IQ for minimal self-heating drift. Use Value: 1 pA bias current prevents electrode polarization error; 10¹² Ω input resistance avoids loading-induced measurement hysteresis. |
Use Scenario: Converting weak photocurrents (100 fA–10 nA) from scientific-grade photodiodes into measurable voltage signals. IC Role / Device Role / Timing Role: Transimpedance amplifier with programmable gain; IQ set to 100 µA for 0.48 MHz bandwidth while retaining sub-pA input error. Use Value: 0.01 pA/√Hz input noise current minimizes shot-noise floor degradation; rail-swing output drives ADC reference buffers directly. |
| Picoammeter Input Stage | Low-Droop Sample/Hold Circuit |
|
Use Scenario: Precision current measurement in semiconductor parameter analyzers and leakage testers requiring femtoampere resolution. IC Role / Device Role / Timing Role: First-stage current-to-voltage converter with guarded input traces and offset-nulling capability. Use Value: Confirmed 1 pA bias current enables <100 fA full-scale resolution; offset nulling via external pot compensates for 10 mV VOS drift over temperature. |
Use Scenario: Holding analog sensor outputs (e.g., thermocouple, strain gauge) for multiplexed ADC conversion with <1 µV/s droop rate. IC Role / Device Role / Timing Role: Unity-gain buffer with ultra-high input impedance isolating hold capacitor from source impedance. Use Value: 10¹² Ω input resistance reduces charge leakage to <1 fA/s on 1 nF hold capacitor - extends hold time beyond 100 seconds. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ultra-low-input-bias-current op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1050CN8#PBF | Fixed 1.2 mA supply current; no IQ programming; 1.5 pA bias current; SO-8 package only | Higher power draw limits battery life; lacks per-channel IQ flexibility for mixed-signal systems | Select when absolute lowest VOS (0.5 mV max) is prioritized over power scalability and DIP mounting. |
| TLC27L4CDR | Quad configuration; 0.6 pA bias current; 16-pin SOIC; fixed 15 µA IQ; no rail-swing output | Lower bias current but 200 mV output headroom limits dynamic range in low-voltage rails | Select for cost-sensitive quad-channel designs where 16-bit ADC interface tolerates 200 mV output loss. |
Compared with LTC1050CN8#PBF and TLC27L4CDR, the ICL7631BCPE+ uniquely combines programmable per-amplifier quiescent current, true rail-to-rail output, and 16-pin DIP packaging - enabling scalable precision analog design without layout redesign or supply rail compromises.
Availability
ICL7631BCPE+ is available at Aetrix Electronics and suitable for battery-powered instruments, low-leakage amplifiers, and long-time-constant integrators requiring stable component supply across extended production cycles.
Supply support for ICL7631BCPE+ 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 precision analog and mixed-signal ICs for demanding industrial, medical, and test equipment applications.
The ICL761X–ICL764X family was engineered specifically for ultra-low-input-bias-current applications including electrometers, picoammeters, and high-impedance sensor interfaces - prioritizing leakage control over raw speed.
FAQ
What is the confirmed input bias current specification for ICL7631BCPE+ at room temperature?
The ICL7631BCPE+ has a typical input bias current of 1 pA at +25°C, with a maximum of 4 nA at +125°C. This value is measured under standard conditions (VSUPP = ±5 V, RS ≤ 100 kΩ) and is validated across the C-temp grade (0°C to +70°C) for the ICL7631BCPE+ variant. The 1 pA figure enables reliable use in picoammeter front-ends and electrometer circuits where sub-picoampere leakage is mandatory.
How does the IOC pin configuration work on ICL7631BCPE+?
The ICL7631BCPE+ uses three dedicated IOC pins (Pins 2, 6, and 12) to set quiescent current per amplifier: connect to V+ for 10 µA, to mid-rail (V− + 0.8 V to V+ − 0.8 V) for 100 µA, or to V− for 1 mA. This per-channel programmability allows mixed-mode operation - e.g., one amplifier at 10 µA for precision DC gain and another at 1 mA for fast settling - without external components.
Does ICL7631BCPE+ support single-supply operation, and what is its common-mode input range in that configuration?
Yes, ICL7631BCPE+ operates from a single 2 V to 16 V supply. With V− grounded and V+ = 5 V, its common-mode input range is –4.0 V to +4.4 V at 10 µA IQ - meaning it accepts inputs slightly below ground (useful for bipolar signal conditioning) and up to 0.6 V below V+. This extended CMVR supports true single-supply sensor interfaces without level-shifting circuitry.
What is the maximum capacitive load ICL7631BCPE+ can drive without instability?
The ICL7631BCPE+ is not guaranteed stable with capacitive loads exceeding 100 pF when configured for unity-gain. For loads >100 pF, a series resistor (≥100 Ω) between output and capacitor restores phase margin. At 1 mA IQ, avoid resistive loads <5 kΩ unless using >10 µF capacitive loads, which introduce a dominant pole that ensures stability even at low impedances.
Is ICL7631BCPE+ pin-compatible with other members of the ICL761X–ICL764X family?
No - ICL7631BCPE+ uses a unique 16-pin DIP pinout specific to triple amplifiers (ICL7631/ICL7632), differing from singles (8-pin), duals (8- or 14-pin), and quads (14- or 16-pin wide SO). Pin functions such as IOC SET and internal N.C. ties (Pins 5/15) are exclusive to the triple configuration. Direct replacement requires matching channel count and package type.
ICL7631BCPE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- CMOS
- Number of Circuits:
- 3
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 1.6V/µs
- Gain Bandwidth Product:
- 1.4 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 1 pA
- Voltage - Input Offset:
- 5 mV
- Current - Supply:
- 1mA (x3 Channels)
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 2 V
- Voltage - Supply Span (Max):
- 16 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
ICL7631BCPE+ FAQ
1.How can I place an order for ICL7631BCPE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for ICL7631BCPE+ 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 ICL7631BCPE+ reliable?
The price and inventory of ICL7631BCPE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ICL7631BCPE+ is usually 5 days.
3.What payment methods are accepted for ICL7631BCPE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ICL7631BCPE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ICL7631BCPE+?
ICL7631BCPE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ICL7631BCPE+ 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 ICL7631BCPE+?
For technical support, including ICL7631BCPE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ICL7631BCPE+ requirements.
6.How does Aetrix verify that ICL7631BCPE+ is sourced from the original manufacturer or authorized distributors?
All ICL7631BCPE+ 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 ICL7631BCPE+ meets industry standards.
7.What is the process for return or replacement of ICL7631BCPE+?
All ICL7631BCPE+ units undergo pre-shipment inspection (PSI). If there is an issue with ICL7631BCPE+, 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 ICL7631BCPE+ part is unused and in its original packaging.
Return procedure for ICL7631BCPE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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