Analog Devices Inc./Maxim Integrated MAX1245BCAP

Overview

MAX1245BCAP from Maxim Integrated is a 12-bit, 8-channel serial analog-to-digital converter (ADC) with integrated track/hold, software-configurable unipolar/bipolar and single-ended/differential inputs, and SPI/QSPI/MICROWIRE-compatible 4-wire serial interface. It operates from a single +2.375V to +3.3V supply, consumes only 0.8mA at 100ksps, and supports 10µA low-power operation at 1ksps - ideal for portable data loggers and battery-powered medical instruments.

For engineers reviewing the MAX1245BCAP datasheet, MAX1245BCAP pinout, MAX1245BCAP application, or MAX1245BCAP equivalent, this page delivers verified technical context, exact pin functions, real-world use scenarios, and two validated alternative parts - all grounded in Maxim's official specifications for the SSOP-20, ±1 LSB INL, 0°C to +70°C variant.

Technical Context

The MAX1245BCAP uses successive-approximation architecture with an internal 12-bit capacitive DAC and on-chip track/hold circuitry. Its acquisition time is fixed at 2.0µs minimum, and conversion timing depends on external clock (1.5MHz typical) or internal clock (1.5MHz when SHDN open, 225kHz when SHDN high).

It supports pseudo-differential sampling via four differential channel pairs (CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7), with COM pin serving as stable reference for single-ended mode. Input voltage range is 0 to VREF (unipolar) or ±VREF/2 (bipolar), and analog inputs tolerate −0.3V to VDD+0.3V with internal clamping diodes.

Key Specifications

Pinout & Package

MAX1245BCAP is housed in a 20-pin SSOP package (30% smaller than 20-pin DIP), with exposed pad not electrically connected. Pin functions are validated per Maxim's official pin description table and typical operating circuit.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1245ACAP, MAX1245BCAP trades 0.5 LSB linearity for lower cost and broader availability; compared with ADS7822U, it provides strobe signaling, wider voltage range, and multi-protocol serial compatibility at the expense of speed and package size.

Availability

MAX1245BCAP is available at Aetrix Electronics and suitable for portable data logging, medical instrumentation, and battery-powered test equipment requiring stable component supply across extended production lifecycles.

Supply support for MAX1245BCAP 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, medical, and communications applications.

The MAX1245 series was designed as a low-power, software-flexible data-acquisition solution for portable and battery-critical systems - emphasizing minimal supply current, wide input configurability, and direct µC interfacing without external components.

FAQ

What is the maximum sampling rate of the MAX1245BCAP?

The MAX1245BCAP achieves a maximum sampling rate of 100ksps when using a 1.5MHz external clock and operating in external clock mode. At this rate, total conversion time is 15 clock cycles (10µs), and supply current is 0.8mA. Lower rates reduce current linearly - e.g., 1ksps draws just 10µA - making MAX1245BCAP highly adaptable to duty-cycled sensing architectures.

Does the MAX1245BCAP require an external reference voltage?

Yes, the MAX1245BCAP requires an external reference voltage applied to the VREF pin. It does not include an internal reference. The device accepts VREF from 0V to VDD, with typical use at 2.048V for clean 0.5mV/LSB resolution. Internal 18kΩ input resistance and 82–120µA bias current must be accounted for in reference driver design.

How does the SHDN pin function on the MAX1245BCAP?

The SHDN pin on the MAX1245BCAP is a three-level control: pulled low → 10µA shutdown mode; left open → 1.5MHz internal clock; pulled high → 225kHz internal clock. This allows hardware-triggered power gating independent of software control, enabling rapid wake-up (<1µs turn-on) and precise clock-rate selection without modifying the control byte.

Can the MAX1245BCAP perform true differential measurements?

No - the MAX1245BCAP implements pseudo-differential sampling. In differential mode, only the positive input (IN+) is actively sampled; the negative input (IN−) serves as a stable reference that must remain within ±0.5 LSB of AGND. True differential rejection is not provided; common-mode rejection relies on external circuit stability and layout.

What serial protocols does the MAX1245BCAP support natively?

The MAX1245BCAP natively supports SPI (CPOL = 0, CPHA = 0), QSPI, MICROWIRE, and TMS320-family DSP interfaces via its 4-wire serial interface (CS, SCLK, DIN, DOUT). SSTRB output enables direct handshake with TMS320 devices, and no external logic is needed for protocol translation - all timing and framing comply with published specifications for these standards.