Analog Devices Inc./Maxim Integrated MAX6738XKRD3

Overview

The MAX6738XKRD3 from Maxim Integrated is a dual-voltage microprocessor supervisor IC with one factory-trimmed reset threshold (VTH1 = 3.075V) and one adjustable reset input (RSTIN, 0.488V reference), open-drain active-low RESET output, manual reset input (MR), and 150ms minimum reset timeout period. It monitors primary I/O supply (VCC1) and secondary core supply (VCC2) in portable, multivoltage systems requiring precise power sequencing and low-quiescent-current supervision.

For engineers reviewing the MAX6738XKRD3 datasheet, MAX6738XKRD3 pinout, MAX6738XKRD3 application, or MAX6738XKRD3 equivalent, this device delivers verified dual-supply monitoring with adjustable threshold capability, SC70-5 packaging for space-constrained designs, and 6µA typical supply current - critical for battery-powered equipment where supply integrity and standby power are tightly coupled.

Technical Context

The MAX6738XKRD3 implements independent voltage comparators for VCC1 and VCC2, each referenced to precision internal thresholds, plus a dedicated 0.488V comparator for RSTIN. Reset assertion occurs when any monitored voltage falls below its threshold, and the internal timer enforces a guaranteed 150ms (min) reset hold time after all supplies recover.

Its open-drain RESET output requires an external pullup and supports bidirectional µP reset interfaces; MR provides CMOS-compatible active-low manual reset with internal 1.5kΩ pullup to VCC1 and 150ms timeout. The device operates across -40°C to +85°C and draws only 6µA total supply current at 3.3V/2.5V supplies.

Key Specifications

Pinout & Package

MAX6738XKRD3 is housed in a 5-pin SC70-5 package (2.0mm × 1.25mm, 0.65mm pitch), optimized for space-constrained portable electronics. Pin 1 is RESET (open-drain active-low), Pin 2 is GND, Pin 3 is MR (manual reset input), Pin 4 is VCC2 (secondary supply input), and Pin 5 is VCC1 (primary supply input).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisor applications.

Compared with MAX6738XKRD3, MAX6739XKRD3 offers push-pull drive but sacrifices bidirectional reset compatibility, while TPS3808G15DBVR reduces functionality and increases quiescent current - making MAX6738XKRD3 the optimal choice for dual-rail, low-power, and interface-flexible designs.

Availability

MAX6738XKRD3 is available at Aetrix Electronics and suitable for portable medical sensors, industrial handheld terminals, notebook computers, GPS tracking modules, and POS equipment requiring stable component supply and long-term production continuity.

Supply support for MAX6738XKRD3 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 solutions for industrial, automotive, and communications markets.

The MAX6736–MAX6745 family was designed specifically for ultra-low-power dual- and triple-voltage supervision in battery-operated and space-constrained systems - emphasizing precision thresholds, minimal supply current, and compact SC70 packaging.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6738XKRD3?

The MAX6738XKRD3 has a factory-trimmed VCC1 reset threshold of 3.075V (±2.5%) and a VCC2 threshold of 2.625V (±2.5%), both specified over the full -40°C to +85°C operating range. These values are confirmed by Maxim's Ordering Information Table 2 and Electrical Characteristics tables, and are encoded in the "RD" suffix of MAX6738XKRD3.

Does the MAX6738XKRD3 support manual reset, and how is it implemented?

Yes, the MAX6738XKRD3 includes a dedicated active-low manual reset (MR) input on Pin 3. Pulling MR low for ≥1µs forces RESET low; RESET remains asserted for 150ms after MR returns high. An internal 1.5kΩ pullup to VCC1 eliminates external biasing, enabling direct connection to pushbutton switches or logic outputs without additional components.

What is the function of the RSTIN pin on the MAX6738XKRD3, and what voltage does it monitor?

The RSTIN pin (Pin 4) on the MAX6738XKRD3 provides an adjustable reset input referenced to a precise 0.488V internal comparator threshold. It enables monitoring of auxiliary voltages - such as battery level or auxiliary DC-DC outputs - using an external resistor divider. Input leakage is <10nA, allowing high-value resistors to minimize system power draw.

Is the MAX6738XKRD3 pin-compatible with other devices in the MAX6736–MAX6745 family?

Yes, the MAX6738XKRD3 shares the identical 5-pin SC70-5 pinout with MAX6736, MAX6737, MAX6739, MAX6740, MAX6742, and MAX6745. Pin assignments (RESET, GND, MR, VCC2, VCC1) are consistent across these variants, enabling drop-in replacement where functional features align - though RESET output type (open-drain vs. push-pull) and feature sets (e.g., PFI/PFO) differ.

What is the supply current consumption of the MAX6738XKRD3 under typical operating conditions?

The MAX6738XKRD3 draws 6µA typical total supply current (ICC1 + ICC2) at +25°C with VCC1 = 3.3V and VCC2 = 2.5V, as measured in the Typical Operating Characteristics section (Figure toc01). This ultra-low quiescent current is maintained across the full -40°C to +85°C temperature range, making it ideal for battery-critical applications.