Analog Devices Inc./Maxim Integrated MAX1085BCSA+T

Overview

MAX1085BCSA+T from Maxim Integrated is a 10-bit, 300ksps serial analog-to-digital converter (ADC) optimized for low-voltage, battery-powered systems. It operates from a single +2.7V to +3.6V supply, integrates a precision +2.5V internal reference (±1 LSB INL, ±15 ppm/°C tempco), features SPI/QSPI/MICROWIRE 3-wire interface, and delivers 60dB SINAD at 75kHz input - ideal for portable medical instruments and remote sensor nodes.

For engineers reviewing the MAX1085BCSA+T datasheet, MAX1085BCSA+T pinout, MAX1085BCSA+T application, or MAX1085BCSA+T equivalent, this page provides verified electrical specs, validated 8-pin SO package mapping, confirmed timing behavior (tACQ = 625ns, tCONV = 3.3µs), and real-world design context for embedded data acquisition with strict power and space constraints.

Technical Context

The MAX1085BCSA+T employs a successive-approximation register (SAR) architecture with integrated track/hold, enabling precise sampling of signals up to 3MHz full-power bandwidth. Its internal 2.5V reference drives both the ADC core and external circuitry, with 4.7µF bypassing required for stable operation and wake-up delay control.

Conversion is initiated by CS falling edge and clocked via SCLK (up to 4.8MHz); output is unipolar 10-bit MSB-first serial data preceded by three leading zeros. Shutdown mode reduces supply current to 2–10µA, with wake-up time dependent on REF capacitor discharge history.

Key Specifications

Pinout & Package

MAX1085BCSA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead(Pb)-free, with standard JEDEC MO-153 footprint (5.0mm × 4.0mm, 1.27mm pitch). Thermal resistance θ_JA = 170°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit serial ADC applications.

Compared with ADS7822U and MAX11100ETE+, the MAX1085BCSA+T uniquely balances 10-bit precision, integrated reference + T/H, ultra-low shutdown current, and compact 8-pin SO packaging - making it optimal for space-constrained, battery-driven systems where component count and power budget are primary constraints.

Availability

MAX1085BCSA+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered data loggers, and industrial process monitoring requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for MAX1085BCSA+T 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 markets.

The MAX1085 belongs to Maxim's precision low-power ADC product line, designed specifically for space- and energy-constrained embedded systems requiring integrated reference, small footprint, and guaranteed performance across industrial temperature ranges.

FAQ

What is the operating temperature range for MAX1085BCSA+T?

The MAX1085BCSA+T is rated for operation from –40°C to +85°C. This extended industrial temperature range is confirmed in the Ordering Information table and Absolute Maximum Ratings section of the official datasheet. The device maintains specified DC accuracy (±0.5 LSB INL) and dynamic performance (60dB SINAD) across this full range, making it suitable for deployment in harsh environments such as factory floors or outdoor sensor nodes. All parametric limits in the Electrical Characteristics tables for MAX1085B apply under these conditions.

Does MAX1085BCSA+T require an external reference voltage?

No, the MAX1085BCSA+T does not require an external reference voltage. It integrates a factory-trimmed +2.50V internal reference with ±2mV initial accuracy and ±15 ppm/°C temperature coefficient. The REF pin (Pin 4) provides this voltage for both internal ADC operation and optional use by external circuitry, and must be bypassed with a 4.7µF capacitor to ensure stability and low-noise performance. Using the internal reference eliminates external component cost and board space while maintaining system-level accuracy.

What is the maximum serial clock frequency supported by MAX1085BCSA+T?

The MAX1085BCSA+T supports a maximum serial clock (SCLK) frequency of 4.8MHz, as specified in the ELECTRICAL CHARACTERISTICS-MAX1085 table under "Serial Clock Frequency". This timing is validated for reliable 300ksps operation with 50% duty cycle and defines the upper limit for data readout speed. Exceeding 4.8MHz may cause timing violations in tCL, tCH, or tCP parameters, leading to incorrect data capture. The device uses 16 clock cycles per conversion, so 4.8MHz SCLK yields the rated 300ksps sampling rate.

How does shutdown mode affect the internal reference in MAX1085BCSA+T?

In shutdown mode (SHDN = low), the internal reference of the MAX1085BCSA+T is disabled and its output at the REF pin drops to near-zero volts. The 4.7µF bypass capacitor discharges slowly during shutdown, causing a wake-up delay of up to 1.4ms upon SHDN deassertion - the time required for the reference to re-stabilize before valid conversions can begin. This behavior is documented in the "Using SHDN to Reduce Supply Current" section and Figure 7 of the datasheet. Designers must account for this delay in low-duty-cycle applications.

Is MAX1085BCSA+T pin-compatible with MAX1084 series devices?

Yes, the MAX1085BCSA+T is pin-compatible with the MAX1084 series (e.g., MAX1084BCSA+) in the same 8-pin SO package. Both share identical pin configuration (VDD, AIN, SHDN, REF, GND, DOUT, CS, SCLK) and mechanical footprint. However, they differ electrically: MAX1085 operates at +2.7V–+3.6V and 300ksps, while MAX1084 requires +4.5V–+5.5V and achieves 400ksps. Swapping them requires verifying supply voltage and timing compliance - the pinout itself is identical and mechanically interchangeable.