Analog Devices Inc./Maxim Integrated MAX187CEWE

Overview

MAX187CEWE from Maxim Integrated is a +5V, 12-bit serial analog-to-digital converter (ADC) with integrated 4.096V buffered reference, 75ksps throughput, and SPI/QSPI/MICROWIRE-compatible 3-wire interface. It features an on-chip track/hold, operates in 0V to 4.096V unipolar input range, and targets low-power sensor and remote DSP applications.

For engineers reviewing the MAX187CEWE datasheet, MAX187CEWE pinout, MAX187CEWE application, or MAX187CEWE equivalent, key selection criteria include internal reference accuracy (±0.5% over temperature), shutdown current (≤10µA), 1.5µs acquisition time, and compatibility with microcontrollers lacking dedicated ADC clock resources.

Technical Context

The MAX187CEWE implements a successive-approximation register (SAR) architecture with integrated track/hold and internal bandgap reference. Its conversion cycle requires 8.5 clock periods (t_CONV), and data is output MSB-first after end-of-conversion (EOC) signaling via DOUT high transition.

It supports unipolar operation only, uses external SCLK for serial readout (up to 5MHz), and relies on CS falling edge to initiate conversion. The SHDN pin enables three-state operation: pulled high enables internal reference; floating disables it for external reference use; pulled low enters shutdown mode.

Key Specifications

Pinout & Package

MAX187CEWE is housed in an 8-pin plastic DIP (PDIP) package with gull-wing leads, compatible with through-hole PCB assembly and socket-based prototyping. Thermal performance supports continuous operation at ambient temperatures up to +70°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and MAX11131AUT+T, the MAX187CEWE uniquely combines internal reference buffering, QSPI/MICROWIRE flexibility, and 8-pin DIP packaging-making it optimal for legacy 5V systems requiring rapid prototyping and minimal external components.

Availability

MAX187CEWE 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.

Supply support for MAX187CEWE 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 industrial, medical, and communications applications.

The MAX187CEWE belongs to Maxim's legacy low-power serial ADC product line, engineered specifically for cost-sensitive, space-constrained embedded systems needing single-supply operation and minimal external components.

FAQ

What is the reference voltage accuracy of the MAX187CEWE over its operating temperature range?

The MAX187CEWE internal reference is specified at 4.096V ±0.5% over the 0°C to +70°C commercial temperature range. At T_A = +25°C, typical output is 4.096V with ±20mV variation; over full range, min/max is 4.060V to 4.132V. This corresponds to ±0.5% full-scale error, enabling 1mV/LSB scaling without external trimming. The MAX187CEWE reference tempco is ±30ppm/°C for the AC grade.

Can the MAX187CEWE operate with an external reference, and how is that configured?

Yes, the MAX187CEWE can operate with an external reference applied to the REF pin. To disable the internal reference, leave the SHDN pin floating (not pulled high or low). The device then accepts external reference voltages from +2.5V to V_DD, with specified accuracy maintained only within that range. An external reference must supply ≤350µA load current and have output impedance ≤10Ω; a 0.1µF bypass capacitor is required at REF. The MAX187CEWE does not regulate or buffer external references.

What is the minimum acquisition time required between conversions for the MAX187CEWE?

The MAX187CEWE requires a minimum track/hold acquisition time (t_ACQ) of 1.5µs after CS goes high before the next conversion can be initiated. This is the shortest interval needed for the internal hold capacitor to settle to within ½ LSB. If the analog source impedance exceeds 5kΩ, acquisition time increases per t_ACQ = 9 × (R_S + 5kΩ) × 16pF, so longer inter-conversion delays may be necessary to maintain accuracy. The MAX187CEWE datasheet specifies this as an absolute minimum under ideal conditions.

How does the MAX187CEWE interface with an SPI master controller?

The MAX187CEWE interfaces with SPI masters using CPOL = 0 and CPHA = 0 configuration. A CS falling edge starts conversion; DOUT goes low during conversion and rises to signal end-of-conversion (EOC). After EOC, 13 SCLK falling edges shift out 12 data bits (MSB first), preceded by a leading high bit. Data is valid on SCLK falling edge and can be latched on rising edge. No additional framing or protocol overhead is required-the MAX187CEWE requires no initialization sequence beyond proper power-up and reference stabilization.

What is the power consumption of the MAX187CEWE in shutdown mode, and how quickly does it wake up?

In shutdown mode (SHDN = low), the MAX187CEWE draws ≤10µA supply current at +25°C and across its full 0°C to +70°C operating range. Wake-up time (t_WAKE) is 2 clock periods (2×t_CLK) - approximately 500ns at 4MHz SCLK - after SHDN is deasserted. This allows rapid reactivation between bursts of sampling. The MAX187CEWE maintains full functionality immediately upon wake-up; no recalibration or settling delay is required beyond the standard 1.5µs acquisition window before the first conversion.