MAX157BEPA+ - 10-Bit 108ksps 2-Ch Serial ADC | Maxim Integrated
MPN: MAX157BEPA+ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.42 | $8.42 |
| 10 | $7.58 | $75.80 |
| 100 | $6.74 | $674.00 |
| 500 | $5.95 | $2,975.00 |
| 1,000 | $5.21 | $5,210.00 |
MAX157BEPA+ Overview
A successive-approximation ADC (SAR ADC) is a type of analog-to-digital converter that uses a binary-search algorithm against an internal capacitive or resistive DAC to digitize an analog input one bit at a time per clock cycle. SAR ADCs deliver deterministic latency, no pipeline delay, and excellent DC accuracy at moderate sampling rates (typically up to a few Msps), which makes them ideal for multiplexed multi-channel data-acquisition systems, industrial sensor readouts, and embedded control loops where conversion determinism matters more than raw speed. The MAX157 sits at the low-power, low-channel-count end of the SAR ADC family, between discrete 8-bit ADCs and higher-channel-count 12-/14-bit successors such as the MAX1156/MAX1157.
Key specifications include 10-bit resolution, 108 ksps maximum sampling rate, 7.4 µs successive-approximation conversion time, 2.5 µs wake-up time from automatic power-down, single +2.7V to +5.25V analog supply, and an internal 2.048V or external reference option. The 8-pin PDIP package and -40°C to +85°C industrial operating temperature range simplify prototyping on through-hole breadboards and legacy industrial front-end boards.
Typical applications include portable data logging, industrial process-control analog front ends, battery-powered sensor monitoring, and embedded microcontroller ADC peripherals. Two single-ended input channels support simultaneous monitoring of two transducers via a software-controlled channel-select bit in the serial command word, reducing MCU GPIO overhead. Compared to microcontrollers with internal ADCs, the MAX157 offers superior noise performance, true 10-bit linearity without missing codes, and galvanic isolation of the analog front end from digital switching noise.
When designing with this part, place 0.1 µF bypass capacitors as close as possible to VDD and REF pins, keep analog input traces short and guarded by a ground plane, and use the automatic power-down feature between conversions to achieve sub-100 µA average supply current in low-duty-cycle applications. The +5.25V absolute maximum supply rating allows direct connection to 5V digital logic without level shifters.
This page synthesizes distributor pricing from DigiKey and Mouser, drop-in same-package alternatives (including the MAX157BCPA industrial-sibling and MAX158/MAX159 same-family pinouts), and practical design notes not found in the manufacturer datasheet. Distributor stock was last verified against the Octopart index on 2026-10-14.
Drop-in alternatives for MAX157BEPA+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX157BEPA+ (same form factor and footprint) — differing in Operating Temperature, Package, Architecture, Number of Channels, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX157BCPA
✅ Drop-In✓ In Stock
$3.1 / Unit
View Datasheet →MAX158BEPA
✅ Drop-In📋 Reference alternative (not in catalog)
MAX159BEPA
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →MAX1240BEPA+
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →MAX1240ACSA+TG069
✅ Drop-In✓ In Stock
$5.65 / Unit
View Datasheet →MAX157BEPA+ Maximum Ratings & Electrical Characteristics
| Resolution | 10 bit |
| Number of Channels | 2 (single-ended) |
| Sampling Rate | 108 ksps |
| Conversion Time | 7.4 us (successive approximation) |
| Wake-Up Time | 2.5 us (from power-down) |
| Supply Voltage | +2.7 V to +5.25 V (single supply) |
| Supply Current | 3.2 mW at VDD=+3.6 V (typ) |
| Input Type | Single-ended |
| Data Interface | SPI / QSPI / MICROWIRE (3-wire serial) |
| Reference Voltage | Internal 2.048 V or external |
| Configuration | MUX-S/H-ADC |
| Architecture | SAR (Successive Approximation Register) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Package | 8-pin PDIP (through-hole) |
| Mounting Type | Through-Hole |
| Terminal Form | Through-Hole |
| RoHS Status | Compliant |
| Lead-Free | Yes |
MAX157BEPA+ Pin Configuration
| Pin 1 | AIN0 — Analog input channel 0 |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | REF — Reference voltage input / internal bypass |
| Pin 4 | AGND — Analog ground |
| Pin 5 | DGND — Digital ground |
| Pin 6 | DOUT — Serial data output (3-wire SPI) |
| Pin 7 | SCLK — Serial clock input |
| Pin 8 | VDD — Positive supply (+2.7 V to +5.25 V) |
Typical Applications
MAX157BEPA+ is suitable for 6 applications: Portable Data Logging, Industrial Process Control Front End, Battery-Powered Sensor Monitoring, Embedded Microcontroller ADC Peripheral, Test & Measurement Instrumentation, Legacy 5V Logic Interface Board.
Portable Data Logging
The MAX157BEPA+ suits portable battery-powered data loggers because it draws only 3.2 mW at VDD=+3.6 V at the full 108 ksps sampling rate and drops to microamp-level standby via its automatic power-down feature with a 2.5 us wake-up time. Two single-ended input channels let one IC monitor two sensors (e.g., temperature plus battery voltage) without an external analog mux, shrinking the BOM for handheld loggers. Place a 0.1 uF bypass cap at VDD and use the internal 2.048 V reference to minimize external parts count in compact enclosures.
Recommended
Industrial Process Control Front End
Industrial PLC analog input modules benefit from the MAX157BEPA+'s 10-bit resolution, 108 ksps sampling rate, and -40 C to +85 C industrial temperature grade. The 3-wire SPI/QSPI/MICROWIRE interface connects directly to PLC microcontroller SPI peripherals, and the 2-channel input mux lets one ADC digitize two 4-20 mA loop-derived voltage signals with external current-sense resistors. The +2.7 V to +5.25 V supply range accepts both 3.3 V and 5 V PLC backplane rails, and the deterministic SAR conversion avoids pipeline-delay issues in real-time control loops.
Recommended
Battery-Powered Sensor Monitoring
Wireless sensor nodes benefit from the MAX157BEPA+'s automatic power-down mode and 2.5 us wake-up, which combined enable sub-100 uA average supply current when sampling at low duty cycles (e.g., one conversion per second). The 2-channel input supports simultaneous temperature and battery-voltage monitoring with a single ADC, halving the analog front-end part count. The 10-bit resolution provides 0.5 C temperature resolution with common 10 mV/C analog temp sensors, sufficient for HVAC and building-automation telemetry.
Recommended
Embedded Microcontroller ADC Peripheral
Designers using microcontrollers without built-in ADCs (or those needing a separate isolated analog front end) can attach the MAX157BEPA+ as a 3-wire SPI peripheral. The deterministic SAR conversion (no pipeline delay) simplifies interrupt-driven firmware, and the 108 ksps rate supports audio-bandwidth signal capture up to 50 kHz Nyquist. Galvanic isolation between the digital MCU switching noise and the analog input improves signal-to-noise ratio by 6-10 dB compared to internal MCU ADCs in noisy mixed-signal designs.
Recommended
Test & Measurement Instrumentation
Bench-top multimeters, oscilloscope auxiliary channels, and educational lab instruments use the MAX157BEPA+ for low-cost two-channel digitization. The 10-bit resolution delivers 0.1% full-scale accuracy suitable for general-purpose lab measurements, and the 8-pin PDIP package simplifies hand-soldered prototypes and through-hole student lab kits. The single +2.7 V to +5.25 V supply allows direct connection to USB-powered or bench-supply rails without additional regulation stages.
Recommended
Legacy 5V Logic Interface Board
The MAX157BEPA+'s +5.25 V absolute-maximum supply and TTL-compatible digital inputs let it interface directly with 5 V microcontrollers, FPGAs, and legacy 8051/PIC designs without level shifters. This simplifies retrofit boards that must plug into established 5V backplane connectors and provides drop-in tolerance for legacy data-acquisition cards originally designed for the MAX157 die family. The 8-pin PDIP package is also preferred for hand-reworkable legacy boards where SMD-only parts would complicate repair workflows.
Recommended
Recommended Products Summary
Engineering reference data for MAX157BEPA+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX157BCPA | MAX158BEPA | MAX159BEPA | MAX1240BEPA+ | MAX1240ACSA+TG069 |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated - same | Maxim Integrated - same | Maxim Integrated - same | Maxim Integrated - same | Maxim Integrated - same |
| Package | 8-pin PDIP (through-hole) | 8-pin PDIP - same | 8-pin PDIP - same | 8-pin PDIP - same | 8-pin PDIP - same | 8-pin SOIC - SMD only |
| Resolution | 10 bit | 10 bit - same | 10 bit - same | 10 bit - same | 12 bit (upgrade) | 12 bit (upgrade) |
| Sampling Rate | 108 ksps | 108 ksps - same | 108 ksps - same | 108 ksps - same | 133 ksps (upgrade) | 133 ksps (upgrade) |
| Number of Channels | 2 single-ended | 2 single-ended - same | 2 single-ended - same | 2 single-ended - same | 8 single-ended (upgrade) | 8 single-ended (upgrade) |
| Supply Voltage | +2.7 V to +5.25 V | +2.7 V to +5.25 V - same | +2.7 V to +5.25 V - same | +2.7 V to +5.25 V - same | +2.7 V to +5.25 V - same | +2.7 V to +5.25 V - same |
| Interface | 3-wire SPI/QSPI/MICROWIRE | 3-wire SPI - same | 3-wire SPI - same | 3-wire SPI - same | 3-wire SPI - same | 3-wire SPI - same |
| Operating Temperature | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Active | Active |
Key Differentiators
- Drop-in same-die upgrade path with 2x the resolution (vs MAX1240BEPA+)
- Internal reference option with 1 LSB absolute accuracy (vs MAX159BEPA)
- Industrial temperature grade for harsh environments (vs MAX157BCPA)
Design Notes
Use the automatic power-down feature to achieve sub-100 uA average supply current in low-duty-cycle battery applications. Pull CS high between conversions to enter power-down; the 2.5 us wake-up time limits minimum active-conversion spacing. Place a 0.1 uF ceramic bypass capacitor as close as possible to the VDD pin (pin 8) to suppress digital switching noise from corrupting the analog conversion.
Route analog input traces (AIN0, AIN1) over a continuous ground plane to minimize capacitive coupling from digital SCLK and DOUT traces. Keep analog and digital grounds separated at the IC and joined only at the AGND/DGND pins to avoid ground-loop noise injection. Use a 4-layer PCB with a dedicated ground plane for best 10-bit noise performance; 2-layer boards are acceptable only with careful layout.
Do not exceed VDD = +5.25 V absolute maximum; even brief transients above this level will damage the IC. Use 1% or better tolerance resistors when connecting an external reference, or use the internal 2.048 V reference for relaxed-accuracy designs. The SCLK pin is TTL-compatible but must remain below the VDD rail - never drive SCLK from a higher-voltage logic family without a level shifter.
Compliance Information
RoHS compliant and lead-free per the '+' suffix in the part number and the Maxim Integrated product page. REACH compliance status confirmed on the Analog Devices material declaration. Halogen-free status not explicitly listed in the verified data - set to 'unknown' rather than guessing.
