MAX146AEAP - 12-Bit 8-Ch 133 kSPS SAR ADC | Analog Devices
MPN: MAX146AEAP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $15.66 | $15.66 |
| 10 | $14.09 | $140.90 |
| 100 | $12.53 | $1,253.00 |
| 500 | $11.27 | $5,635.00 |
| 1,000 | $10.02 | $10,020.00 |
| 2,500 | $8.95 | $22,375.00 |
MAX146AEAP Overview
A SAR ADC is a type of analog-to-digital converter that uses a binary-search successive-approximation algorithm to convert an analog input to a digital code in a fixed number of clock cycles per conversion. SAR ADCs sit between delta-sigma converters (which trade speed for resolution) and flash ADCs (which offer speed but consume large power and silicon area), making them the workhorse choice for multiplexed data-acquisition channels at medium speeds (10 kSPS to 1 MSPS) and moderate resolution (10 to 16 bits).
Key features of the MAX146AEAP include 133 kSPS throughput, low 1.3 mA operating supply current (shutting down to 1 microamp between conversions), single +2.7V to +5.25V analog supply operation, hard-wired active-low SHDN-bar input plus software-controllable auto-shutdown at end-of-conversion, an internal 2.5V reference with ±1.5% adjustable range via the reference-buffer amplifier, and integrated input protection rated to ±16V (allowing direct connection to industrial sensor lines without external clamping).
The device uses a capacitive-DAC SAR core with auto-calibrated MSBs and a low-drift buried-zener reference, achieving ±1 LSB INL (max) and ±1 LSB DNL (no missing codes at 12 bits). The high-bandwidth track-and-hold supports input bandwidths above 2 MHz, preserving accurate capture of fast transient signals. A serial digital interface runs from a separate +2.7V to +5.25V digital supply, enabling mixed-voltage designs where the ADC and downstream microcontroller use different rails.
Typical applications for the MAX146AEAP include portable battery-powered data loggers, multichannel sensor-front-end digitizers (thermocouple, strain-gauge bridge, pressure transducer), industrial process-control instrumentation with 4-20 mA loop inputs, patient-monitoring medical devices, and automotive body-system sensor acquisition. The integrated 8-channel mux and internal reference minimize BOM cost and PCB area.
When designing with the MAX146AEAP, place a 0.1 microfarad ceramic bypass capacitor within 5 mm of AVDD and a 1 microfarad tantalum or ceramic capacitor between REF and AGND, and connect AVSS/DVSS to a clean ground plane. Drive unused analog input pins to a valid DC level (AVDD or AVSS) to prevent input-channel crosstalk; do not leave analog inputs floating.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MAX146AEAP — 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 MAX146AEAP (same form factor and footprint) — differing in Resolution, Operating Temperature, Package, RoHS Status, Number of Input Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX147AEAP
✅ Drop-In✓ In Stock
$4.88 / Unit
View Datasheet →MAX147AEAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX146ACAP
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1202ACAP
✅ Drop-In✓ In Stock
$7.17 / Unit
View Datasheet →MAX1165AEUI+T
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$8.9 / Unit
View Datasheet →MAX146AEAP Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Input Channels | 8 (single-ended) / 4 (differential) |
| Conversion Rate | 133 kSPS |
| Architecture | SAR (Successive Approximation) |
| Analog Supply Voltage (AVDD) | +2.7 V to +5.25 V |
| Digital Supply Voltage (DVDD) | +2.7 V to +5.25 V |
| Supply Current (operating) | 1.3 mA (typ) |
| Supply Current (shutdown) | 1 microA (typ) |
| Internal Reference Voltage | 2.5 V (MAX146 variant) |
| Reference Adjustment Range | ±1.5% |
| Input Overvoltage Protection | ±16 V |
| INL (max) | ±1 LSB |
| DNL (max) | ±1 LSB (no missing codes) |
| Track-and-Hold Bandwidth | 2 MHz (typ) |
| Serial Interface | SPI / QSPI / MICROWIRE-compatible |
| Shutdown Mode | Hardware SHDN-bar + software auto-shutdown |
| Package | 20-pin SSOP |
| Operating Temperature | -40 C to +85 C |
| RoHS Status | Compliant |
MAX146AEAP Pin Configuration
| Pin 1 | CH0 — Analog input channel 0 |
| Pin 2 | CH1 — Analog input channel 1 |
| Pin 3 | CH2 — Analog input channel 2 |
| Pin 4 | CH3 — Analog input channel 3 |
| Pin 5 | CH4 — Analog input channel 4 |
| Pin 6 | CH5 — Analog input channel 5 |
| Pin 7 | CH6 — Analog input channel 6 |
| Pin 8 | COM — Common analog input for single-ended conversions |
| Pin 9 | REF — Reference voltage input/output (MAX147 external, MAX146 internal 2.5V) |
| Pin 10 | AGND — Analog ground |
| Pin 11 | AVDD — Analog supply (+2.7V to +5.25V) |
| Pin 12 | AVSS — Analog negative supply |
| Pin 13 | SCLK — Serial clock input |
| Pin 14 | DOUT — Serial data output |
| Pin 15 | DIN — Serial data input |
| Pin 16 | CS-bar — Active-low chip select |
| Pin 17 | SHDN-bar — Active-low shutdown input |
| Pin 18 | DVDD — Digital supply (+2.7V to +5.25V) |
| Pin 19 | DGND — Digital ground |
| Pin 20 | CH7 — Analog input channel 7 |
Typical Applications
MAX146AEAP is suitable for 7 applications: Portable Battery-Powered Data Loggers, Multichannel Sensor-Front-End Digitizers, Industrial Process Control and 4-20 mA Loop Inputs, Patient Monitoring Medical Devices, Automotive Body-System Sensor Acquisition, IoT and Smart-Home Sensor Hubs, Test and Measurement Instrumentation.
Portable Battery-Powered Data Loggers
The MAX146AEAP's 1.3 mA active supply current and 1 microA shutdown current combined with 133 kSPS throughput make it ideal for portable battery-powered data loggers sampling 4-8 thermocouple or strain-gauge channels at low duty cycle. The internal 2.5V reference eliminates the need for a separate reference IC, reducing BOM cost and quiescent draw. In a typical thermocouple logger, all 8 channels are scanned at 1 kSPS aggregate, the converter auto-shuts down between conversions, and 4 AA cells power the design for months. Hard-wired SHDN-bar allows a microcontroller to gate the ADC's supply current entirely during deep-sleep intervals.
Recommended
Multichannel Sensor-Front-End Digitizers
The MAX146AEAP's 8-input multiplexer (8 single-ended or 4 differential) lets one ADC IC digitize temperature, pressure, strain, and flow sensors simultaneously - replacing 8 single-channel ADCs. The ±16V overvoltage-protected analog inputs survive industrial miswiring (a 24V sensor supply accidentally applied to a 5V channel) without smoke. 133 kSPS throughput captures fast-changing process variables at kHz rates, and the 1 LSB INL keeps absolute readings within ±0.024 percent. Differential inputs reject 50/60 Hz common-mode noise picked up by long sensor cables.
Recommended
Industrial Process Control and 4-20 mA Loop Inputs
In a 4-20 mA loop-input module, 125 ohm sensing resistors generate 0.5-2.5 V signals that the MAX146AEAP digitizes across 8 isolated channels. The ±16V input protection withstands the line transients that 24V industrial wiring induces, removing the need for external TVS clamp diodes and reducing PCB cost. The MAX146AEAP's split analog/digital supply rails plus an internal 2.5V reference simplify galvanic-isolator designs where one side runs from loop power and the other from logic power. SPI runs through the isolator to the host microcontroller.
Recommended
Patient Monitoring Medical Devices
The MAX146AEAP's low 1 microA shutdown current and ±16V-protected 8-channel mux support multi-parameter patient monitors (ECG, SpO2, respiration, temperature) where battery life and patient safety are paramount. The MAX146AEAP's 133 kSPS throughput captures ECG waveforms at standard 500 Hz sampling per channel across all 8 channels simultaneously. Solid pinouts with isolated digital ground and 12-bit no-missing-codes performance produce diagnostic-grade waveform fidelity. The internal 2.5V reference keeps the input-referred noise below 5 microV rms and the bipolar inputs handle ±5V sensor outputs.
Recommended
Automotive Body-System Sensor Acquisition
The MAX146AEAP is well-suited to automotive body-system modules measuring 8 analog sensors - seat-occupancy pressure, climate-control temperatures, battery-cell voltages - where the 12V automotive supply bus is stepped down to 5V. Each MAX146AEAP input tolerates the ±16V transient pulses generated by load-dump events, protecting the converter directly without external TVS clamps. The 8-channel mux replaces eight single-channel ADCs, halving PCB area. The SHDN-bar logic pin lets the body-control module wake the ADC only when actively sampling, saving 1.3 mA during ignition-off quiescent states.
Recommended
IoT and Smart-Home Sensor Hubs
Smart-home sensor hubs reading 8 environmental inputs (temperature, humidity, CO2, light, motion-derived analog, water-leak sensing, soil moisture, airflow) use the MAX146AEAP to consolidate multiple sensor analog signals into a single SPI/QSPI bus interfaced to a low-cost Wi-Fi or BLE microcontroller. The MAX146AEAP's 1 microA shutdown current ensures battery-powered multi-year sensor life, and the internal 2.5V reference eliminates the cost of an external reference IC, keeping the BOM under $1.50 per sensor hub. The 2 MHz track-and-hold bandwidth captures fast motion-event pulses accurately.
Recommended
Test and Measurement Instrumentation
Bench-top multimeters, datalogging oscilloscopes, and lab-grade signal analyzers benefit from the MAX146AEAP's ±16V-protected inputs and 8-channel mux, which lets one ADC service multiple signal-conditioning channels behind relays or FET muxes. The MAX146AEAP's 1 LSB INL/DNL and 133 kSPS throughput deliver 12-bit precision at digitizer-class speeds. Internal 2.5V reference provides stable readings across production calibration cycles, and SPI compatibility allows direct connection to FPGA-based capture engines at full 133 kSPS without wait states.
Recommended
Recommended Products Summary
Engineering reference data for MAX146AEAP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX147AEAP | MAX146ACAP | MAX1202ACAP | MAX1165AEUI+ |
|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) |
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same |
| Resolution | 12 bits | 12 bits | 12 bits | 14 bits (better) | 12 bits |
Key Differentiators
- Internal 2.5V reference eliminates external reference IC cost (vs MAX147AEAP)
- Higher resolution (14 bits) with integrated PGA (vs MAX1202ACAP)
- Higher sampling rate and more input channels (vs MAX1165AEUI+)
Design Notes
Place a 0.1 microfarat ceramic bypass capacitor within 5 mm of the AVDD pin and a 0.1 microfarat ceramic bypass on DVDD, both connected directly to a clean ground plane. Add a 1 microfarad (tantalum or ceramic) bulk capacitor between the REF pin and AGND for reference-noise reduction. Keep analog and digital grounds separate on the schematic and join them at a single point beneath the IC. Use a guard trace or ground plane around the analog input pins to minimize digital-switching coupling into high-impedance sensor signals.
When the MAX146AEAP is active, AVDD and DVDD typically draw 1.3 mA combined from a +2.7V to +5.25V supply. Tie SHDN-bar high (DVDD) for continuous-conversion mode, or drive it low between conversions for sub-microwatt quiescent power. The MAX146AEAP's software auto-shutdown mode (set via the configuration byte) automatically powers down the ADC at end-of-conversion, achieving typ. 1 microA between samples - critical for battery-powered data loggers.
Drive analog input traces with a low-impedance source (buffer amplifier or op amp follower); 0.1 nA input leakage through 10 kiloohms can cause 1 LSB of error at 12-bit resolution. Tie unused analog inputs to a known DC level (AVDD or AVSS) - never leave them floating - to prevent the input mux from injecting crosstalk onto the selected channel. For cable runs longer than 100 mm, add a small RC filter (100 ohm + 1 nF) at each analog input to reject RF pickup without degrading the MAX146AEAP's 2 MHz track-and-hold bandwidth.
Do not decouple the REF pin to AVDD or AVSS - decouple it to AGND only, since the reference source-follower expects AGND as its return path. Sequencing: drive SHDN-bar high AFTER AVDD stabilizes, never before; activating SHDN-bar with AVDD=0 can latch up the input ESD cells. When migrating from MAX146 (internal reference) to MAX147 (external reference), supply the REF pin with a low-noise buffered 2.5V source such as a MAX6125.
Compliance Information
RoHS-compliant per Analog Devices / Maxim product page (MAX146AEAP+ variant). Not AEC-Q100 qualified - for automotive applications consult the dedicated MAX22530/MAX22531 automotive-grade parts.
