Analog Devices Inc./Maxim Integrated MAX6855UK38D1+T

Overview

The MAX6855UK38D1+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring active-high push-pull reset output, manual reset input (MR), and factory-trimmed 3.800V reset threshold (±2.5%). It delivers ultra-low 170nA typical supply current and guarantees valid reset assertion down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices requiring long-term reliability under brownout conditions.

For engineers reviewing the MAX6855UK38D1+T datasheet, MAX6855UK38D1+T pinout, MAX6855UK38D1+T application, or MAX6855UK38D1+T equivalent, this device supports critical low-power system initialization, manual recovery, and transient-immune voltage monitoring in space-constrained embedded designs where supply current and VCC operating margin are design-critical.

Technical Context

This device implements a precision bandgap-based voltage monitor with 0.5% hysteresis, a fixed 10ms minimum reset timeout period (D1 option), and MR input with 250ns propagation delay and 1µs minimum pulse width. Its internal 10kΩ MR pullup eliminates external components while maintaining immunity to 40µs VCC transients at 100mV overdrive.

The active-high push-pull RESET output drives high to VCC (≥0.8×VCC at 500µA source) and sinks low to ≤0.3V (at 1.2mA sink), ensuring robust logic-level compatibility across 1.2V–5.5V supply rails without external pullups or level shifters.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (1.6mm × 2.9mm × 1.1mm), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with TPS3837K33DBVR and MAX6361KA29D2+T, the MAX6855UK38D1+T uniquely combines 3.800V precision threshold, 10ms fast timeout, active-high push-pull drive, and nanopower 170nA operation - making it the sole option for next-gen medical wearables demanding both high-VCC margin and decade-scale battery life.

Availability

MAX6855UK38D1+T is available at Aetrix Electronics and suitable for glucose monitoring systems, patient vital sign monitors, and handheld diagnostic tools requiring stable component supply with full traceability and long-lifecycle support.

Supply support for MAX6855UK38D1+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) designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications - emphasizing reliability, low power, and small-footprint integration.

The MAX6855UK38D1+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for battery-critical medical and portable electronics where sub-µA quiescent current and guaranteed reset validity at ultra-low VCC are non-negotiable.

FAQ

What is the exact reset threshold voltage of the MAX6855UK38D1+T?

The MAX6855UK38D1+T has a factory-trimmed reset threshold voltage of 3.800V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "38" corresponds to 3.800V nominal. The MAX6855UK38D1+T maintains guaranteed reset assertion down to VCC = +1.1V, independent of threshold accuracy.

Does the MAX6855UK38D1+T include a watchdog timer function?

No, the MAX6855UK38D1+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input; the MAX6855UK38D1+T is a manual-reset-only supervisory circuit with MR input and active-high push-pull RESET output - confirmed by its absence in all WDI-related electrical characteristics and functional diagrams.

What is the reset timeout period for the MAX6855UK38D1+T?

MAX6855UK38D1+T uses the D1 reset timeout option, providing a minimum reset timeout period of 10ms (typical 15ms, maximum 25ms). This is encoded in the part number suffix "D1", referenced in Table 4 (Reset Timeout Periods) and confirmed in the Ordering Information section specifying "D1" as the timeout code for this variant.

Can the MAX6855UK38D1+T operate with a 1.2V supply?

Yes, the MAX6855UK38D1+T operates across VCC = 1.2V to 5.5V. Its supply current remains ultra-low (170nA typ at 1.8V), and RESET output is guaranteed valid down to VCC = +1.1V. However, at 1.2V, the 3.800V reset threshold cannot be asserted - the device functions only as a supervisor for rails ≥3.8V; VCC = 1.2V is supported solely for biasing internal circuitry during low-VCC brownout detection.

Is the MAX6855UK38D1+T pin-compatible with other MAX68xx devices?

The MAX6855UK38D1+T shares the same 5-pin SOT23-5 package and pinout as MAX6854/MAX6856/MAX6858/MAX6860–MAX6869 variants, but pin functionality differs: MAX6855UK38D1+T uses Pin 1 for active-high RESET (not open-drain or active-low), and lacks WDI or CT pins. Direct substitution is not recommended without verifying RESET polarity, threshold, and timeout compatibility in the target application.