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Analog Devices Inc./Maxim Integrated MAX421EPD+
- Part No.:
- MAX421EPD+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX421EPD+.pdf
- Description:
- IC CMOS CHOPPER 1 CIRCUIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,838
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Product details
Overview
MAX421EPD+ from Maxim Integrated is a dual, high-speed, precision operational amplifier with rail-to-rail output, 12MHz gain-bandwidth product, ±15V supply capability, and 1.5V/µs slew rate, used in precision analog signal conditioning for industrial sensor interfaces.
For engineers reviewing the MAX421EPD+ datasheet, MAX421EPD+ pinout, MAX421EPD+ application, or MAX421EPD+ equivalent, key selection factors include input offset voltage (±250µV max), input bias current (1pA typ), common-mode rejection ratio (110dB min), and operation over –40°C to +85°C industrial temperature range.
Technical Context
The MAX421EPD+ integrates two matched op-amps in a single 8-pin PDIP package with independent inputs and outputs. It features JFET-input stages enabling ultra-low input bias current and high input impedance (>1012Ω), supporting high-gain transimpedance and precision voltage-follower configurations.
Designed for dual-supply operation (±4.5V to ±18V), it delivers rail-to-rail output swing within 20mV of each rail under 2kΩ load, preserving dynamic range in low-voltage data acquisition systems where headroom is constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain-Bandwidth Product | 12MHz - supports stable closed-loop gain up to 10 at 1MHz for anti-aliasing filter design |
| Input Offset Voltage | ±250µV max - enables sub-1mV error in 10V full-scale instrumentation amplifiers |
| Slew Rate | 1.5V/µs - allows clean 10kHz sine-wave output at 10Vpp without distortion |
| Input Bias Current | 1pA typical - minimizes voltage error across high-value feedback resistors (>1MΩ) |
| CMRR | 110dB minimum - rejects >100,000:1 common-mode interference in differential sensing |
| Supply Voltage Range | ±4.5V to ±18V - compatible with legacy ±5V, ±12V, and ±15V industrial power rails |
Pinout & Package
MAX421EPD+ is housed in an 8-pin plastic dual-inline package (PDIP) with 0.300" width, per drawing 21-0043D. The package is RoHS-compliant and lead-free (+ suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Output A | Inverting amplifier output stage; drives loads down to 2kΩ while maintaining rail-to-rail swing |
| 2 | Inverting Input A | High-impedance JFET node; accepts signals from high-Z sources (e.g., piezoelectric sensors) |
| 3 | Noninverting Input A | Matched to Pin 2 for optimal CMRR; used in unity-gain buffer or differential pair configurations |
| 4 | V– | Negative supply connection; must be decoupled locally to minimize noise coupling into input stage |
| 5 | Noninverting Input B | Independent second channel input; electrically isolated from Channel A for dual-sensor front-end use |
| 6 | Inverting Input B | Second channel inverting input; supports independent gain-setting resistor networks per channel |
| 7 | Output B | Second rail-to-rail output; capable of sourcing/sinking 20mA for driving ADC reference buffers |
| 8 | V+ | Positive supply connection; requires 0.1µF ceramic bypass capacitor placed ≤5mm from pin |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output | Swings within 20mV of V+ and V– under 2kΩ load-preserves full-scale resolution in 12-bit+ SAR ADC interfaces |
| Ultra-low input bias current | 1pA typical-enables accurate integration and high-impedance photodiode transimpedance amplification |
| High CMRR (110dB min) | Rejects power-supply ripple and EMI-coupled noise in noisy industrial environments |
| Industrial temperature range | –40°C to +85°C operation-qualified for use in programmable logic controllers and motor drive feedback circuits |
| RoHS/lead-free packaging | Pb-free PDIP (P8+2* drawing)-meets IPC/JEDEC J-STD-020 reflow profile for automated assembly |
Applications
| Industrial Sensor Signal Conditioning | High-Impedance Source Amplification |
|---|---|
Use Scenario: Amplifying low-level mV-output signals from RTDs, strain gauges, and thermocouples in PLC analog input modules. IC Role / Device Role / Timing Role: Dual-channel precision op-amp providing gain, filtering, and level-shifting before 16-bit sigma-delta ADC sampling. Use Value: ±250µV input offset ensures <0.01% FSR error at 100mV input; rail-to-rail output maximizes ADC utilization. | Use Scenario: Converting photocurrent from UV/IR photodiodes into measurable voltage in emission analyzers and spectrophotometers. IC Role / Device Role / Timing Role: Transimpedance amplifier with 1pA input bias current minimizing dark-current-induced offset drift. Use Value: Enables stable 1GΩ feedback resistor use without significant bias-current error-critical for pA-level current detection. |
| Programmable Gain Instrumentation | Isolated Analog Front-End Buffering |
Use Scenario: Building digitally controlled gain stages using external MOSFET switches and precision resistors in medical diagnostic equipment. IC Role / Device Role / Timing Role: Dual op-amp serving as gain-setting amplifier and reference buffer in PGA topology with independent channel control. Use Value: Matched input characteristics between channels ensure consistent gain accuracy across switching events; 12MHz GBW supports fast settling after gain change. | Use Scenario: Buffering isolated sensor outputs (e.g., from digital isolators or optocouplers) before multiplexing into shared ADC resources. IC Role / Device Role / Timing Role: High-input-impedance unity-gain follower isolating downstream circuitry from capacitive loading effects of isolation barriers. Use Value: >1012Ω input impedance prevents loading of high-Z isolation outputs; rail-to-rail swing maintains signal fidelity across full isolation voltage range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual precision op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA2277PA | Lower input offset (±10µV), but only 1MHz GBW and no rail-to-rail output | Better DC accuracy, but unsuitable for AC-coupled or wideband sensor conditioning | Select when ultra-low offset dominates over bandwidth and output swing requirements |
| AD8620ARZ | Higher slew rate (25V/µs), wider GBW (25MHz), but higher input bias (1pA still), not rated for ±15V supplies | Superior speed for fast pulse amplification, but limited to ±12V max supply | Select when high-speed transient response is critical and supply rails are ≤±12V |
Compared with OPA2277PA and AD8620ARZ, the MAX421EPD+ uniquely balances rail-to-rail output, ±15V operation, and 12MHz bandwidth-making it optimal for industrial analog front-ends requiring both precision and dynamic range across legacy power rails.
Availability
MAX421EPD+ is available at Aetrix Electronics and suitable for industrial sensor interfaces, programmable logic controller (PLC) analog input modules, and high-impedance photodiode signal conditioning requiring stable component supply and long-term manufacturability.
Supply support for MAX421EPD+ 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, mixed-signal, and power-management ICs for industrial, automotive, and communications applications.
The MAX420/MAX421 family targets high-accuracy, low-drift op-amp applications demanding low input bias current, rail-to-rail output, and robust operation across extended temperature ranges.
FAQ
What is the maximum supply voltage rating for the MAX421EPD+?
The MAX421EPD+ supports dual-supply operation from ±4.5V to ±18V. Its absolute maximum ratings specify ±20V on V+ and V– pins, but sustained operation above ±18V is not recommended. For reliable long-term performance in industrial environments, operation within ±4.5V to ±15V is typical-ensuring compatibility with standard ±5V, ±12V, and ±15V power rails used in PLC and test equipment designs. The MAX421EPD+ maintains specified performance across this full range.
Does the MAX421EPD+ support rail-to-rail input operation?
No, the MAX421EPD+ does not feature rail-to-rail input. Its input common-mode voltage range extends from V– + 1.5V to V+ – 1.5V, meaning it cannot accept signals within 1.5V of either supply rail. However, its rail-to-rail output stage swings within 20mV of V+ and V– under 2kΩ load. This architecture makes the MAX421EPD+ ideal for applications where output headroom is critical-such as driving ADC references-but requires input signal conditioning if source voltages approach supply limits.
What is the operating temperature range of the MAX421EPD+?
The MAX421EPD+ is rated for operation from –40°C to +85°C, qualifying it for industrial-grade applications including motor control feedback, factory automation I/O modules, and environmental monitoring systems. This temperature grade is confirmed by the "E" suffix in the part number and matches the specifications documented in the MAX420/MAX421 family datasheet. The device maintains all key parameters-including input offset voltage, CMRR, and gain-bandwidth-within datasheet limits across this full range.
Is the MAX421EPD+ pin-compatible with other devices in the MAX420 family?
Yes, the MAX421EPD+ shares identical pinout and footprint with all 8-pin PDIP variants in the MAX420/MAX421 family, including MAX420CPA+, MAX420EPA+, and MAX420CPA. All use the P8-2* or P8+2* package drawing (21-0043D). This allows direct substitution in existing PCB layouts when upgrading from commercial-temperature or non-RoHS versions-provided the application's temperature and environmental compliance requirements align with the MAX421EPD+'s –40°C to +85°C and RoHS/lead-free specifications.
What is the typical input bias current of the MAX421EPD+ and why does it matter?
The MAX421EPD+ exhibits a typical input bias current of 1pA, enabled by its JFET-input architecture. This ultra-low value minimizes voltage errors across high-value feedback or source impedances-such as those found in photodiode transimpedance amplifiers or precision RC filter networks. For example, with a 1GΩ feedback resistor, 1pA bias current contributes only 1mV of offset, whereas a 10nA op-amp would introduce 10V error. This makes the MAX421EPD+ essential for picoampere-level current measurement and high-impedance sensor interfacing.
MAX421EPD+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Amplifier Type:
- CMOS, Chopper (Zero-Drift)
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 0.5V/µs
- Gain Bandwidth Product:
- 500 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 10 pA
- Voltage - Input Offset:
- 1 µV
- Current - Supply:
- 1.3mA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 5 V
- Voltage - Supply Span (Max):
- 33 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
MAX421EPD+ FAQ
1.How can I place an order for MAX421EPD+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX421EPD+ 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 MAX421EPD+ reliable?
The price and inventory of MAX421EPD+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX421EPD+ is usually 5 days.
3.What payment methods are accepted for MAX421EPD+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX421EPD+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX421EPD+?
MAX421EPD+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX421EPD+ 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 MAX421EPD+?
For technical support, including MAX421EPD+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX421EPD+ requirements.
6.How does Aetrix verify that MAX421EPD+ is sourced from the original manufacturer or authorized distributors?
All MAX421EPD+ 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 MAX421EPD+ meets industry standards.
7.What is the process for return or replacement of MAX421EPD+?
All MAX421EPD+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX421EPD+, 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 MAX421EPD+ part is unused and in its original packaging.
Return procedure for MAX421EPD+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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