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Analog Devices Inc./Maxim Integrated MAX4291EXK
- Part No.:
- MAX4291EXK
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
MAX4291EXK.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT SC70-5
- Quantity:
- Payment:
- Shipping:
Inventory:5,973
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Product details
Overview
The MAX4291EXK from Maxim Integrated is a single-channel, micropower, rail-to-rail input/output operational amplifier optimized for ultra-low-voltage, high-precision portable systems. It operates from 1.8V to 5.5V single supply (or ±0.9V to ±2.75V dual), draws only 100µA per amplifier, delivers 500kHz gain-bandwidth, achieves 120dB open-loop gain, and features ±200µV input offset voltage - enabling accurate signal conditioning in 2-cell battery-powered instrumentation and sensor interfaces.
For engineers reviewing the MAX4291EXK datasheet, MAX4291EXK pinout, MAX4291EXK application, or MAX4291EXK equivalent, key selection considerations include its guaranteed 1.8V operation, rail-to-rail I/O swing within 46mV of rails into 2kΩ, unity-gain stability with ≤100pF capacitive loads, absence of phase reversal on overdriven inputs, and SC70-5 package compatibility with space-constrained PCB layouts.
Technical Context
The MAX4291EXK employs a composite NPN/PNP input stage enabling true rail-to-rail common-mode input range (0V to VCC) and eliminating phase reversal during input overdrive. Its output stage uses complementary push-pull circuitry to achieve rail-to-rail swing while sourcing/sinking up to ~3.5mA at 1.8V supply when driving within 100mV of either rail.
This architecture supports precision DC-coupled amplification and comparator use in low-power systems, with input bias current polarity inversion near mid-supply requiring matched source impedances to minimize offset error - a design requirement confirmed across all temperature ranges and supply voltages in the datasheet's Figures 1a/1b and electrical tables.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.8V to 5.5V single supply - enables direct operation from depleted two-cell alkaline (1.8V end-of-life) or single Li-ion batteries without regulation. |
| Quiescent Current | 100µA per amplifier - allows >1000 hours of continuous operation on a 100mAh coin cell in always-on sensor nodes. |
| Gain-Bandwidth Product | 500kHz - supports stable amplification of DC–10kHz physiological signals (e.g., ECG, strain gauge outputs) with ≥40dB gain. |
| Input Offset Voltage | ±200µV (max) - ensures ≤0.2% error in 1V full-scale 12-bit ADC front-ends without trimming. |
| Output Swing (2kΩ) | Within 46mV of rails - preserves dynamic range in 1.8V systems where headroom is critical for signal fidelity. |
| Open-Loop Gain | 120dB (RL = 100kΩ) - guarantees <0.0025% gain error in unity-gain buffers used for reference buffering. |
| THD + Noise | 0.017% at 1kHz - meets audio-grade requirements for low-noise microphone preamps in portable devices. |
Pinout & Package
The MAX4291EXK is housed in a 5-pin SC70 package (3.0mm × 1.7mm × 0.9mm), compatible with SOT23-5 footprints and suitable for high-density portable PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN+) | Noninverting Input | Differential input node with rail-to-rail common-mode range (0V to VCC); requires matched impedance to IN− to minimize bias-current-induced offset. |
| 2 (IN−) | Inverting Input | Differential input node with identical rail-to-rail range; internal 10.6kΩ series resistors and back-to-back diode stacks provide ±1.8V differential input protection. |
| 3 (OUT) | Amplifier Output | Rail-to-rail output capable of sourcing/sinking ≥3.5mA at 1.8V while staying within 100mV of VCC/VEE - drives 2kΩ loads directly without external buffers. |
| 4 (VEE) | Negative Supply | Ground reference for single-supply operation; must be bypassed with 100nF capacitor to minimize PSRR degradation at high frequencies. |
| 5 (VCC) | Positive Supply | Primary power input (1.8V–5.5V); requires local 100nF ceramic decoupling placed adjacent to pin to suppress supply noise coupling into sensitive analog paths. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-Rail Input/Output | Enables full utilization of 1.8V supply range: input accepts 0V–1.8V signals; output delivers 0.046V–1.754V into 2kΩ - maximizing SNR in battery-powered data acquisition. |
| No Phase Reversal on Overdrive | Prevents catastrophic latch-up in sensor interfaces where input transients exceed rails - eliminates need for external clamping diodes in strain gauge or thermocouple front-ends. |
| Unity-Gain Stable (≤100pF) | Allows direct connection to ADC input capacitors or long PCB traces without compensation networks - simplifies layout in compact wearable designs. |
| Ultra-Low 100µA Quiescent Current | Reduces self-heating to <0.1°C in sealed enclosures, preserving offset stability in precision digital scales and medical sensors over temperature. |
| Guaranteed 1.8V Operation | Supports uninterrupted function as two-cell alkaline batteries discharge from 3.0V to 1.8V - extends usable battery life by 25% versus 2.0V-minimum op amps. |
Applications
| Portable Digital Scales | Sensor Signal Conditioning |
|---|---|
Use Scenario: Weighing platforms using load cells with mV-level output requiring amplification before 12-bit ADC conversion. IC Role / Device Role / Timing Role: Precision DC-coupled instrumentation amplifier with rail-to-rail I/O to maximize dynamic range from 1.8V supply. Use Value: ±200µV offset ensures <0.02% linearity error across 0–5kg range; 100µA IQ enables multi-year battery life in consumer bathroom scales. | Use Scenario: Strain gauge bridges in industrial torque sensors operating from 2-cell AA batteries. IC Role / Device Role / Timing Role: Low-drift, rail-to-rail output buffer isolating bridge from ADC input capacitance. Use Value: 500kHz GBW supports fast step-response to mechanical shock; 46mV rail margin preserves resolution at battery end-of-life (1.8V). |
| Two-Cell Battery Monitoring | Low-Power Cellular Front-Ends |
Use Scenario: Real-time voltage/current monitoring in rechargeable NiMH battery packs for portable test equipment. IC Role / Device Role / Timing Role: Current-sense amplifier in high-side configuration with PNP transistor feedback loop (Fig. 11). Use Value: 120dB open-loop gain ensures <0.1% gain error in 50mA current sensing; 1.8V min supply matches battery cutoff threshold. | Use Scenario: Microphone preamplifier in GSM handsets requiring low-noise, low-power analog front-end. IC Role / Device Role / Timing Role: Single-supply, rail-to-rail op amp providing 20dB gain with minimal THD+N distortion. Use Value: 0.017% THD+N at 1kHz meets EN 50371 audio quality standards; SC70 package saves 40% board area vs. SOIC-8 alternatives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar micropower, rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP6001T-E/OT | Higher 150µA IQ, lower 100kHz GBW, ±1.8mV VOS (max), same SC70-5 package | Less suitable for high-precision DC measurements but adequate for AC-coupled audio or general-purpose buffering | Select when cost sensitivity outweighs precision requirements and bandwidth needs are ≤50kHz |
| TSV911ICT | Lower 80µA IQ, higher 8MHz GBW, ±1.5mV VOS (max), same SC70-5 footprint | Better for wideband sensor interfaces but exhibits higher offset drift and reduced rail-to-rail output drive into 2kΩ | Select when system requires >100kHz signal bandwidth and can tolerate higher offset error in DC-critical paths |
Compared with MCP6001T-E/OT and TSV911ICT, the MAX4291EXK uniquely balances ultra-low IQ (100µA), precision (±200µV VOS), and rail-to-rail output drive into 2kΩ - making it optimal for battery-powered instrumentation where accuracy, power, and output swing must coexist.
Availability
The MAX4291EXK is available at Aetrix Electronics and suitable for portable electronic equipment, battery-powered instrumentation, and two-cell battery-operated systems requiring stable component supply across extended production lifecycles.
Supply support for MAX4291EXK 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 MAX4291EXK belongs to Maxim's ultra-small, micropower op amp product line engineered specifically for high-accuracy signal conditioning in space- and energy-constrained portable systems powered by 1.8V–5.5V sources.
FAQ
What is the minimum operating voltage for the MAX4291EXK?
The MAX4291EXK is fully specified and guaranteed to operate down to 1.8V single supply (or ±0.9V dual supply). Datasheet Figure 4 confirms stable performance at 1.8V across -40°C to +85°C, and typical operation extends to 1.5V - making MAX4291EXK ideal for two-cell alkaline or NiMH battery systems nearing end-of-life.
Does the MAX4291EXK support rail-to-rail input and output simultaneously?
Yes, the MAX4291EXK provides true rail-to-rail input common-mode range (0V to VCC) and rail-to-rail output swing (within 46mV of both rails into 2kΩ). This simultaneous capability is verified in the Electrical Characteristics table (VCM = 0 to VCC; VOH/VOL specs) and Typical Operating Characteristics (Figures 3, 7a–7c), ensuring full signal range utilization in 1.8V systems.
Can the MAX4291EXK be used as a comparator?
Yes, the MAX4291EXK can be used as a rail-to-rail I/O comparator, with propagation delay dependent on input overdrive (Figure 8). However, supply current increases significantly - up to 1.5mA at 1.8V - due to output-stage overdrive. For sustained comparator operation, consider dedicated low-power comparators; MAX4291EXK is best suited for infrequent, low-duty-cycle comparisons.
What is the maximum capacitive load the MAX4291EXK can drive without oscillation?
The MAX4291EXK is unity-gain stable for capacitive loads up to 100pF, as confirmed in the Features list and Load Resistor vs. Capacitive Load graph (Figure 19). Driving larger loads (e.g., ADC input capacitance + trace capacitance >100pF) requires an isolation resistor (RISO) between output and load - though this introduces gain error via voltage division with RL.
How does input bias current behavior affect PCB layout for the MAX4291EXK?
The MAX4291EXK's NPN/PNP input stage causes input bias current polarity to invert near mid-supply (VCC/2), creating offset errors if source impedances at IN+ and IN− differ. To minimize this, match external resistor values feeding both inputs (Figures 1a/1b), keep trace lengths equal, and avoid routing high-impedance nodes near noisy digital lines - practices validated in the Applications Information section.
MAX4291EXK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Packaging:
- Bulk
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.2V/µs
- Gain Bandwidth Product:
- 500 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 15 nA
- Voltage - Input Offset:
- 400 µV
- Current - Supply:
- 100µA
- Current - Output / Channel:
- 20 mA
- Voltage - Supply Span (Min):
- 1.8 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-5
MAX4291EXK FAQ
1.How can I place an order for MAX4291EXK through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX4291EXK 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 MAX4291EXK reliable?
The price and inventory of MAX4291EXK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX4291EXK is usually 5 days.
3.What payment methods are accepted for MAX4291EXK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX4291EXK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX4291EXK?
MAX4291EXK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX4291EXK 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 MAX4291EXK?
For technical support, including MAX4291EXK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX4291EXK requirements.
6.How does Aetrix verify that MAX4291EXK is sourced from the original manufacturer or authorized distributors?
All MAX4291EXK 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 MAX4291EXK meets industry standards.
7.What is the process for return or replacement of MAX4291EXK?
All MAX4291EXK units undergo pre-shipment inspection (PSI). If there is an issue with MAX4291EXK, 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 MAX4291EXK part is unused and in its original packaging.
Return procedure for MAX4291EXK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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