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Analog Devices Inc./Maxim Integrated MAX494CSD
- Part No.:
- MAX494CSD
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX494CSD.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,150
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Product details
Overview
MAX494CSD 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 portable instrumentation and low-voltage data acquisition systems.
For engineers reviewing the MAX494CSD datasheet, MAX494CSD pinout, MAX494CSD application, or MAX494CSD equivalent, this page delivers verified specifications, package mapping, real-world use cases, and validated alternative options - all grounded in the official Maxim datasheet Rev 2 (9/96) and confirmed SO-14 packaging data.
Technical Context
The MAX494CSD 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 no phase reversal under overdriven inputs.
Each amplifier delivers 25nV/√Hz input voltage noise, drives ≥1kΩ loads, and sustains stable operation with >1nF capacitive loads - achieved via internal compensation optimized for low quiescent current (150µA/amplifier) without external isolation resistors in most configurations.
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 3V and 5V battery-powered systems without level-shifting. |
| Gain-Bandwidth Product | 500kHz - enables stable amplification of low-frequency sensor signals (e.g., thermocouples, strain gauges) with minimal phase lag. |
| Input Offset Voltage | ±200µV (max at +25°C) - ensures sub-LSB error when buffering 12-bit ADCs like MAX187 with 4.096V reference. |
| Quiescent Current | 150µA per amplifier - allows four-channel signal conditioning in ultra-low-power applications with <600µA total ICC. |
| Output Swing | VOH ≥ VCC − 75mV, VOL ≤ VEE + 75mV (RL = 100kΩ) - preserves full dynamic range near supply rails for maximum SNR in low-voltage designs. |
| CMRR / PSRR | 90dB / 110dB (typical) - rejects supply ripple and common-mode interference in noisy industrial or portable environments. |
| Input Noise Density | 25nV/√Hz - maintains signal integrity for microvolt-level analog front-ends without requiring additional filtering. |
Pinout & Package
MAX494CSD is supplied in a 14-pin SO (Small Outline) package, industry-standard footprint compatible with automated assembly and IPC-7351B SOIC14 metrics. Pin pitch is 1.27mm; body width is 3.9mm; total length is 8.65mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT1 | Amplifier 1 output - connects directly to downstream circuitry (e.g., ADC input, filter stage) with rail-to-rail swing capability. |
| 2 | IN1− | Inverting input of Amp 1 - used for feedback networks in inverting configurations; matched impedance minimizes bias-current-induced offset. |
| 3 | IN1+ | Noninverting input of Amp 1 - accepts high-impedance sensor signals; protected by internal back-to-back diodes for ±0.7V differential fault tolerance. |
| 4 | VEE | Negative power supply - tied to ground in single-supply mode; must be bypassed with 1µF + 0.1µF ceramic capacitor for stability. |
| 5 | IN2+ | Noninverting input of Amp 2 - electrically identical to IN1+; supports independent channel routing in multi-sensor systems. |
| 6 | IN2− | Inverting input of Amp 2 - shares same protection and bias characteristics as IN1−; enables matched dual-channel instrumentation. |
| 7 | OUT2 | Amplifier 2 output - provides second buffered channel; layout symmetry with OUT1 reduces crosstalk in adjacent traces. |
| 8 | VCC | Positive power supply - supplies all four amplifiers; requires local decoupling to suppress supply-induced noise coupling between channels. |
| 9 | IN3− | Inverting input of Amp 3 - supports third independent gain stage; pin assignment follows standard SOIC14 op-amp layout convention. |
| 10 | IN3+ | Noninverting input of Amp 3 - identical electrical behavior to IN1+/IN2+; enables three-channel simultaneous signal conditioning. |
| 11 | OUT3 | Amplifier 3 output - completes third channel; output isolation from other channels exceeds 125dB (typical amp-to-amp isolation). |
| 12 | IN4+ | Noninverting input of Amp 4 - enables fourth parallel signal path; critical for multi-channel data loggers or sensor fusion architectures. |
| 13 | IN4− | Inverting input of Amp 4 - matches IN1−/IN2−/IN3− performance; supports fully independent fourth channel with no shared nodes. |
| 14 | OUT4 | Amplifier 4 output - final buffered output; all four outputs are fully isolated and capable of driving 1kΩ loads independently. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input common-mode range | Extends 0.25V beyond VEE and VCC - eliminates need for level-shifting when interfacing with sensors operating near supply rails. |
| No phase reversal on overdrive | Guaranteed operation without latch-up or polarity inversion even when inputs exceed VEE/VCC - improves system robustness in transient-prone environments. |
| Capacitive load drive capability | Stable with >1nF loads - removes requirement for output isolation resistors in most data acquisition circuits, preserving DC accuracy. |
| Low input offset voltage tempco | ±2µV/°C - limits drift-induced error to <100µV over 0°C to +70°C industrial range, critical for unattended long-duration measurements. |
| High large-signal voltage gain | 108dB (typical) - ensures <0.001% gain error in precision gain stages, supporting accurate calibration and ratiometric sensing. |
| Unity-gain stable | No external compensation required - simplifies design of voltage followers and noninverting buffers without risk of oscillation. |
Applications
| Portable ECG Monitor | Battery-Powered pH Meter |
|---|---|
|
Use Scenario: Amplifying microvolt-level biopotential signals from dry electrodes in handheld medical devices with 3.3V Li-ion supply. IC Role / Device Role / Timing Role: Quad buffer and gain stage for simultaneous lead-I, lead-II, lead-III, and Wilson central terminal acquisition. Use Value: Rail-to-rail input enables full utilization of 0–3.3V ADC range; 150µA/amplifier extends battery life to >100 hours per charge. |
Use Scenario: Conditioning mV-level output from glass pH electrode in field-deployable water quality analyzers powered by AA batteries. IC Role / Device Role / Timing Role: High-input-impedance buffer and 10× gain stage preceding 16-bit sigma-delta ADC. Use Value: 200µV offset contributes <0.01pH error; 25nV/√Hz noise ensures resolution better than 0.001pH in 1Hz bandwidth. |
| Multi-Channel Thermocouple Logger | Low-Voltage Industrial Sensor Hub |
|
Use Scenario: Cold-junction compensation and linearization of eight K-type thermocouples in compact DIN-rail mounted data logger. IC Role / Device Role / Timing Role: Four MAX494CSDs provide 16-channel instrumentation-grade amplification with matched gain and offset. Use Value: 90dB CMRR rejects 50/60Hz pickup from shared AC mains; 500kHz GBW supports fast thermocouple response during ramp tests. |
Use Scenario: Signal conditioning for 4–20mA loop-powered sensors in smart factory edge nodes operating from 24V DC with local 3.3V regulation. IC Role / Device Role / Timing Role: Input buffer, level shifter, and anti-alias filter driver for mixed-signal SoC with integrated SAR ADC. Use Value: Single-supply +2.7V operation allows direct interface with LDO output; 110dB PSRR prevents supply noise from corrupting 12-bit conversions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV2464IDR | Higher quiescent current (550µA/amplifier), lower GBW (6.4MHz), no guaranteed phase-reversal immunity. | Better suited for higher-speed, AC-coupled applications; less optimal for ultra-low-power DC precision. | Select TLV2464IDR only if bandwidth >1MHz is required and supply current budget allows >2× increase per channel. |
| AD8604ARUZ | Lower offset (60µV max), lower noise (12nV/√Hz), but higher supply current (240µA/amplifier) and narrower supply range (2.7V–5.5V). | Preferred for highest-accuracy 16-bit+ systems where power is secondary to precision; not rated for 6V operation. | Choose AD8604ARUZ when offset and noise dominate design constraints and 6V operation is unnecessary. |
Compared with TLV2464IDR and AD8604ARUZ, the MAX494CSD uniquely balances micropower operation (150µA), rail-to-rail functionality, guaranteed no-phase-reversal behavior, and 6V absolute maximum supply - making it irreplaceable in cost-sensitive, battery-constrained, wide-supply industrial designs.
Availability
MAX494CSD is available at Aetrix Electronics and suitable for portable equipment, battery-powered instruments, and low-voltage data acquisition systems requiring stable component supply across extended production lifecycles.
Supply support for MAX494CSD 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.
The MAX492/MAX494/MAX495 family was engineered specifically for micropower, rail-to-rail precision signal conditioning in space- and energy-constrained systems - targeting battery-operated instrumentation where DC accuracy and supply flexibility are paramount.
FAQ
Is MAX494CSD recommended for new designs?
No, MAX494CSD is marked "Not Recommended for New Designs" because its wafer process is obsolete. However, Aetrix Electronics maintains active inventory and supply-chain continuity for legacy industrial and medical programs still relying on MAX494CSD. For new designs, consult Maxim's official replacement guidance or consider AD8604ARUZ or TLV2464IDR with appropriate validation.
What is the operating temperature range for MAX494CSD?
The MAX494CSD is specified for 0°C to +70°C ambient operation (C-grade). This is confirmed in the Ordering Information table, where "MAX494CSD" maps to the "C" suffix denoting the commercial temperature range. Extended ranges (–40°C to +85°C or –55°C to +125°C) require different suffixes (E or M) and are not applicable to the CSD variant.
Does MAX494CSD support single-supply operation below 3V?
Yes, MAX494CSD supports single-supply operation down to +2.7V, as explicitly stated in the General Description and DC Electrical Characteristics tables. At 2.7V, it maintains rail-to-rail input/output swing, 150µA max supply current per amplifier, and functional stability - enabling direct use with LiFePO₄ or two-cell alkaline batteries.
Can MAX494CSD drive capacitive loads without external compensation?
Yes, MAX494CSD is designed to drive capacitive loads exceeding 1nF stably, as confirmed in the Applications Information section and Figure 5 (Capacitive-Load Stable Region). It remains stable with 1000pF pure capacitance (Figure 6) and up to 400pF while sourcing ~100µA - eliminating need for output isolation resistors in most data acquisition layouts.
What is the pin configuration difference between MAX494CSD and MAX492/MAX495?
MAX494CSD uses a 14-pin SO package with four fully independent op amps (pins 1–3, 5–7, 9–11, 12–14), whereas MAX492 is dual (8-pin DIP/SO) and MAX495 is single (8-pin SO/µMAX). The MAX494CSD pinout follows industry-standard SOIC14 op-amp layout - no NULL pins, unlike MAX495 - and all four amplifiers share common VCC (pin 8) and VEE (pin 4).
MAX494CSD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- 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:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
MAX494CSD FAQ
1.How can I place an order for MAX494CSD through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX494CSD 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 MAX494CSD reliable?
The price and inventory of MAX494CSD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX494CSD is usually 5 days.
3.What payment methods are accepted for MAX494CSD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX494CSD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX494CSD?
MAX494CSD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX494CSD 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 MAX494CSD?
For technical support, including MAX494CSD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX494CSD requirements.
6.How does Aetrix verify that MAX494CSD is sourced from the original manufacturer or authorized distributors?
All MAX494CSD 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 MAX494CSD meets industry standards.
7.What is the process for return or replacement of MAX494CSD?
All MAX494CSD units undergo pre-shipment inspection (PSI). If there is an issue with MAX494CSD, 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 MAX494CSD part is unused and in its original packaging.
Return procedure for MAX494CSD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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