Analog Devices Inc./Maxim Integrated MAX187BEPA+

Overview

MAX187BEPA+ from Maxim Integrated is a +5V, low-power, 12-bit successive-approximation analog-to-digital converter (ADC) with integrated track/hold, on-chip 4.096V buffered reference, and 3-wire SPI-compatible serial interface. It delivers 75ksps throughput, ±½ LSB integral nonlinearity (A-grade), 1.5µs acquisition time, and operates in 0°C to +70°C industrial temperature range within an 8-pin PDIP package.

For engineers reviewing the MAX187BEPA+ datasheet, MAX187BEPA+ pinout, MAX187BEPA+ application, or MAX187BEPA+ equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative parts with documented differences, and supply-ready availability details - all specific to the MAX187BEPA+ variant.

Technical Context

The MAX187BEPA+ implements a single-supply +5V 12-bit SAR ADC architecture with internal track/hold and monolithic bandgap reference. Its conversion cycle requires 8.5 clock periods (t_CONV), and it uses unipolar serial output with MSB-first format, including one leading high bit signaling end-of-conversion.

It supports three-level SHDN control: pulled high enables internal 4.096V reference; floating disables it for external reference use; pulled low enters shutdown mode (<10µA I_DD). The 3-wire interface (CS, SCLK, DOUT) is electrically and timing-compatible with SPI, QSPI, and MICROWIRE protocols without external logic.

Key Specifications

Pinout & Package

MAX187BEPA+ is housed in an 8-pin plastic dual-inline package (PDIP) with 0.3-inch width and through-hole mounting. Pin functions are validated per Maxim's official datasheet revision 1 (March 2012).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit serial ADC applications.

Compared with MAX187CEPA+, the MAX187BEPA+ offers tighter DC accuracy (±½ vs. ±1 LSB INL) at identical price point and package - making it preferred for calibrated instrumentation. Compared with ADS7816U, MAX187BEPA+ trades speed for integration (on-chip reference + T/H), reducing BOM count and layout complexity in space-constrained designs.

Availability

MAX187BEPA+ is available at Aetrix Electronics and suitable for portable data logging, remote DSP, isolated data acquisition, and high-accuracy process control requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX187BEPA+ 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, communications, and consumer systems.

The MAX187BEPA+ belongs to Maxim's precision data-converter product line, designed specifically for low-power, space-constrained, single-supply applications demanding integrated reference and simple digital interfacing - such as battery-operated sensors and distributed control nodes.

FAQ

What is the reference voltage configuration of the MAX187BEPA+?

The MAX187BEPA+ features an on-chip, laser-trimmed, buffered 4.096 V bandgap reference. When the SHDN pin is pulled high, this internal reference is enabled and drives the REF pin. This eliminates the need for external reference components and ensures stable 1 mV/LSB scaling across temperature. The MAX187BEPA+ does not require an external reference unless SHDN is left floating - a configuration that disables the internal reference and allows external reference use.

Does the MAX187BEPA+ support SPI communication without additional level-shifting?

Yes, the MAX187BEPA+ supports direct SPI communication with 3.3 V or 5 V microcontrollers. Its digital inputs (CS, SCLK, SHDN) accept VIH ≥ 2.4 V and VIL ≤ 0.8 V, and its DOUT output drives VOH ≥ 4.0 V at 1 mA load - fully compliant with standard 5 V SPI logic levels. No level-shifting circuitry is needed when interfacing with 5 V MCUs; for 3.3 V MCUs, verify that their output high level meets MAX187BEPA+'s 2.4 V VIH minimum - most modern 3.3 V devices satisfy this.

What is the maximum recommended source impedance for the AIN pin of the MAX187BEPA+?

The MAX187BEPA+ specifies a maximum source impedance of 5 kΩ for optimal AC performance. Its input capacitance is 16 pF, and acquisition time t_ACQ = 9 × (R_S + R_IN) × 16 pF, where R_IN = 5 kΩ. For R_S ≤ 5 kΩ, t_ACQ remains at the guaranteed 1.5 µs minimum. Exceeding 5 kΩ increases acquisition time and may degrade THD and SINAD - especially above 10 kHz input frequencies. Use a unity-gain buffer (e.g., MAX400 or OP07) for high-impedance sensors.

How does shutdown mode affect conversion timing in the MAX187BEPA+?

In shutdown mode (SHDN low), the MAX187BEPA+ draws <10 µA and halts all internal operations, including reference buffer and clock generation. To resume conversion, SHDN must be deasserted (pulled high or floated), after which a 2-clock-cycle wake-up delay (t_WAKE) occurs before CS can initiate a valid conversion. During this wake-up, the internal reference stabilizes - no external delay is required beyond t_WAKE. Full accuracy resumes immediately after the first completed conversion post-wake-up.

Can the MAX187BEPA+ operate with an external reference while retaining its internal reference pin functionality?

No - the MAX187BEPA+ cannot simultaneously use its internal reference and accept an external reference. The SHDN pin selects the mode: pulled high enables the internal 4.096 V reference and drives REF; floating disables the internal reference and configures REF as an input for external reference (2.5 V to VDD). There is no provision for internal reference bypass or dual-reference operation. Using an external reference requires disabling the internal buffer, and the REF pin then serves solely as an input - not an output.