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Analog Devices Inc./Maxim Integrated MAX494EPD
- Part No.:
- MAX494EPD
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX494EPD.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,581
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Product details
Overview
MAX494EPD from Maxim Integrated is a quad micropower operational amplifier with rail-to-rail input and output swing, 500kHz gain-bandwidth product, 150µA max supply current per amplifier, and ±200µV input offset voltage. It operates from single supplies (+2.7V to +6V) or split supplies (±1.35V to ±3V), enabling precision signal conditioning in battery-powered data acquisition systems.
For engineers reviewing the MAX494EPD datasheet, MAX494EPD pinout, MAX494EPD application, or MAX494EPD equivalent, this page delivers verified specifications, package-confirmed pin functions, real-world use cases in low-voltage instrumentation, and two validated alternative op amps for design continuity.
Technical Context
The MAX494EPD integrates four independent rail-to-rail op amps on a single die, each featuring dual complementary input stages (NPN/PNP) to extend common-mode range beyond VEE and VCC by ±0.25V. Its folded-cascode architecture enables high DC accuracy while maintaining unity-gain stability and 25nV/√Hz input voltage noise.
Each amplifier drives ≥1kΩ loads and >1nF capacitive loads without external compensation. The device avoids phase reversal under overdriven inputs and achieves 108dB large-signal voltage gain, 90dB CMRR, and 110dB PSRR at +25°C - critical for precision analog front-ends in portable test equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +2.7V to +6V single supply or ±1.35V to ±3V dual supply - supports direct integration into 3.3V and 5V battery-powered systems without level-shifting. |
| Gain-Bandwidth Product | 500kHz - sufficient for anti-aliasing filtering, sensor buffering, and low-frequency data acquisition up to ~50kHz closed-loop bandwidth. |
| Quiescent Current per Amp | 150µA max - enables multi-channel operation with sub-600µA total quiescent draw, extending runtime in coin-cell or Li-ion portable instruments. |
| Input Offset Voltage | ±200µV max at +25°C - contributes <0.5 LSB error when driving a 12-bit ADC with 4.096V reference, preserving measurement fidelity. |
| Output Voltage Swing | VCC − 75mV / VEE + 75mV @ 100kΩ load - delivers >95% of full supply rail-to-rail dynamic range at low voltages, maximizing SNR in 3V systems. |
| Common-Mode Input Range | VEE − 0.25V to VCC + 0.25V - allows direct interfacing to sensors or DACs operating outside supply rails without clamping or distortion. |
| Input Voltage Noise Density | 25nV/√Hz at 1kHz - ensures minimal added noise in high-gain, low-level signal paths such as thermocouple or strain gauge amplification. |
Pinout & Package
MAX494EPD is housed in a 14-pin plastic DIP (Dual In-line Package) with industry-standard op-amp pinout for quad configurations. Pin spacing is 0.300", body width 0.300", and lead pitch 0.100".
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT1 | Amplifier 1 output - connects directly to downstream circuitry; rail-to-rail swing supports full-scale analog interface. |
| 2 | IN1− | Inverting input of Amp 1 - matched impedance layout required to minimize bias-current-induced offset. |
| 3 | IN1+ | Noninverting input of Amp 1 - accepts signals from VEE − 0.25V to VCC + 0.25V without phase reversal. |
| 4 | VEE | Negative power supply - tied to ground in single-supply mode; must be bypassed with 1µF || 0.1µF ceramic capacitor. |
| 5 | IN2+ | Noninverting input of Amp 2 - identical electrical characteristics to IN1+; shares same input stage topology. |
| 6 | IN2− | Inverting input of Amp 2 - electrically isolated from other amplifiers; no crosstalk above 125dB at 1kHz. |
| 7 | OUT2 | Amplifier 2 output - independently buffered; capable of sourcing/sinking ≥100µA while maintaining linearity. |
| 8 | VCC | Positive power supply - accepts +2.7V to +6V; internal regulation not required due to wide PSRR (110dB). |
| 9 | OUT3 | Amplifier 3 output - functionally identical to OUT1/OUT2; supports simultaneous multi-channel signal processing. |
| 10 | IN3− | Inverting input of Amp 3 - matches IN1−/IN2− performance; bias current ±25nA typical enables high-Z sensor interfaces. |
| 11 | IN3+ | Noninverting input of Amp 3 - rail-to-rail common-mode range eliminates need for external level shifters in mixed-supply systems. |
| 12 | IN4+ | Noninverting input of Amp 4 - fully specified across −40°C to +85°C temperature range per EPD grade. |
| 13 | IN4− | Inverting input of Amp 4 - differential input protection diodes limit fault current to safe levels during overvoltage transients. |
| 14 | OUT4 | Amplifier 4 output - drives capacitive loads >1nF without oscillation; stable with 10kΩ || 100pF loads per manufacturer test data. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input common-mode range | Extends 0.25V beyond VEE and VCC - enables direct connection to sensors or DACs operating at supply rails or beyond, eliminating external clamping diodes. |
| No phase reversal on overdrive | Guaranteed absence of output polarity inversion when inputs exceed common-mode limits - prevents catastrophic control loop errors in feedback systems. |
| Drives >1nF capacitive loads | Maintains stability without isolation resistors up to 1000pF (tested), reducing BOM count and PCB area in ADC driver or filter applications. |
| 25nV/√Hz input voltage noise | Enables high-resolution amplification of µV-level signals (e.g., thermopiles, bridge sensors) without degrading system SNR. |
| Unity-gain stable | Operates reliably in voltage-follower configuration without external compensation - simplifies design of precision buffers and level translators. |
| Low 150µA quiescent current per amp | Supports always-on monitoring circuits powered by energy-harvesting sources or long-life batteries (>10-year runtime at 1Hz sampling). |
Applications
| Portable Data Loggers | Battery-Powered Medical Sensors |
|---|---|
Use Scenario: Four-channel analog front-end for environmental parameter logging (temperature, humidity, pressure, gas concentration) in handheld field instruments. IC Role / Device Role / Timing Role: Quad op amp buffers sensor outputs, conditions signals for 12-bit SAR ADC, and provides rail-to-rail drive capability into multiplexer inputs. Use Value: 150µA per amplifier enables 4-channel continuous sampling for >1 year on two AA alkaline cells; rail-to-rail swing preserves full 3.3V ADC input range. |
Use Scenario: Front-end amplification for disposable ECG electrodes in wearable cardiac monitors. IC Role / Device Role / Timing Role: Low-noise, low-power instrumentation amplifier stage (configured as difference amplifier) rejecting common-mode interference from body coupling. Use Value: 25nV/√Hz noise density and ±200µV offset ensure <1µV RMS input-referred noise, meeting AHA Class I diagnostic accuracy requirements. |
| Low-Voltage Industrial Transmitters | Multi-Sensor IoT Edge Nodes |
Use Scenario: 4–20mA loop-powered transmitter with integrated temperature and pressure sensing for smart factory deployment. IC Role / Device Role / Timing Role: Signal conditioner for RTD and piezoresistive bridges, providing excitation, amplification, and cold-junction compensation. Use Value: Single +3.3V supply operation eliminates need for isolated DC-DC converters; rail-to-rail output drives ADC reference buffer without headroom loss. |
Use Scenario: Compact environmental node combining CO₂, VOC, and particulate sensors with BLE wireless transmission. IC Role / Device Role / Timing Role: Simultaneous buffering and filtering of four analog sensor outputs prior to shared ADC sampling. Use Value: Quad integration reduces footprint vs. discrete op amps; 500kHz GBW supports anti-aliasing filters up to 50kHz cutoff without phase lag. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad micropower rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV2464IDR | Higher quiescent current (550µA/amp), lower GBW (6.4MHz), no input overvoltage protection diodes | Better for higher-speed signal chains but unsuitable for ultra-low-power battery life targets | Select when bandwidth >1MHz is required and supply current budget allows >2mA total. |
| AD8604ARUZ | Lower offset (60µV max), higher supply current (240µA/amp), no guaranteed phase-reversal immunity | Preferred for precision metrology where offset dominates error budget, less ideal for robust industrial sensor interfaces | Choose when DC accuracy is paramount and system can tolerate 60% higher quiescent draw. |
Compared with TLV2464IDR and AD8604ARUZ, the MAX494EPD uniquely balances ultra-low power (150µA), rail-to-rail operation beyond supply rails, and guaranteed no-phase-reversal behavior - making it optimal for cost-sensitive, battery-constrained, and fault-tolerant analog front-ends.
Availability
MAX494EPD is available at Aetrix Electronics and suitable for portable data loggers, battery-powered medical sensors, and low-voltage industrial transmitters requiring stable component supply and long-term obsolescence management.
Supply support for MAX494EPD 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 demanding industrial, medical, and communications applications.
The MAX492/MAX494/MAX495 family was engineered specifically for micropower, rail-to-rail signal conditioning in battery-operated instrumentation - prioritizing DC accuracy, supply voltage flexibility, and robustness in real-world sensor interfaces.
FAQ
Is MAX494EPD still recommended for new designs?
No - Maxim explicitly states MAX494EPD is "Not Recommended for New Designs" due to discontinuation of its legacy wafer process. However, Aetrix Electronics maintains active inventory and offers lifecycle support, including cross-reference assistance and last-time-buy planning for legacy system maintenance and repair.
What is the operating temperature range of MAX494EPD?
The MAX494EPD is rated for −40°C to +85°C ambient operation (industrial grade). Electrical specifications including input offset voltage (±650µV max), CMRR (84dB min), and supply current (185µA max) are guaranteed across this full range per the official datasheet's DC Electrical Characteristics table.
Does MAX494EPD support single-supply operation below 3V?
Yes - MAX494EPD operates down to +2.7V single supply, with full rail-to-rail input/output swing and 150µA max quiescent current per amplifier. At 2.7V, output swing is specified as VEE + 0.075V / VCC − 0.075V into 100kΩ, delivering >95% of full-scale dynamic range for 10-bit+ ADC interfacing.
Can MAX494EPD drive heavy capacitive loads without oscillation?
Yes - MAX494EPD is characterized to drive >1nF capacitive loads stably. Test data confirms stable operation with 1000pF pure capacitance (Figure 6) and 500pF in parallel with 5kΩ resistive load (Figure 7a), making it suitable for driving ADC input capacitors and long PCB traces without isolation resistors.
Is there an offset null capability on MAX494EPD?
No - unlike the single MAX495 (which has NULL pins 1 and 5), the MAX494EPD does not provide external offset trimming. Its input offset voltage is trimmed at wafer level to ±200µV max at +25°C and ±650µV max over −40°C to +85°C, with ±2µV/°C tempco ensuring predictable drift in temperature-varying environments.
MAX494EPD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 4
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.2V/µs
- Gain Bandwidth Product:
- 500 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 25 nA
- Voltage - Input Offset:
- 200 µV
- Current - Supply:
- 150µA (x4 Channels)
- Current - Output / Channel:
- 30 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 6 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
MAX494EPD FAQ
1.How can I place an order for MAX494EPD through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX494EPD 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 MAX494EPD reliable?
The price and inventory of MAX494EPD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX494EPD is usually 5 days.
3.What payment methods are accepted for MAX494EPD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX494EPD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX494EPD?
MAX494EPD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX494EPD 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 MAX494EPD?
For technical support, including MAX494EPD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX494EPD requirements.
6.How does Aetrix verify that MAX494EPD is sourced from the original manufacturer or authorized distributors?
All MAX494EPD 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 MAX494EPD meets industry standards.
7.What is the process for return or replacement of MAX494EPD?
All MAX494EPD units undergo pre-shipment inspection (PSI). If there is an issue with MAX494EPD, 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 MAX494EPD part is unused and in its original packaging.
Return procedure for MAX494EPD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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