Analog Devices Inc./Maxim Integrated MAX6738XKLD3

Overview

The MAX6738XKLD3 from Maxim Integrated is a low-power dual-voltage microprocessor supervisor IC with one factory-trimmed reset threshold (VTH1 = 4.625V) 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 supply VCC1 (e.g., 5V I/O rail) and secondary supply VCC2 (e.g., 3.3V or 2.5V core rail) in portable and multivoltage systems.

For engineers reviewing the MAX6738XKLD3 datasheet, MAX6738XKLD3 pinout, MAX6738XKLD3 application, or MAX6738XKLD3 equivalent, key selection considerations include its SC70-5 package footprint, 6µA quiescent current, dual-supply monitoring capability with adjustable RSTIN, -40°C to +85°C operating range, and compatibility with battery-powered and space-constrained embedded designs.

Technical Context

The MAX6738XKLD3 implements dual-supply supervision using independent comparators for VCC1 and VCC2, plus an auxiliary comparator for the RSTIN input referenced to a precision 0.488V internal bandgap. Its reset assertion logic triggers when any monitored voltage falls below its respective threshold and holds RESET low for ≥150ms after all voltages recover.

It features a dedicated active-low MR input with internal 1.5kΩ pullup to VCC1, enabling external pushbutton or logic-initiated reset; the MR pulse width must exceed 1µs, and MR-to-RESET delay is 300ns. The open-drain RESET output requires an external pullup resistor and supports bidirectional µP reset interfaces.

Key Specifications

Pinout & Package

MAX6738XKLD3 is housed in a 5-pin SC70-5 package (2.0mm × 1.25mm, 0.65mm pitch), optimized for high-density portable designs. 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-supply supervisory applications.

Compared with MAX6739XKLD3, the MAX6738XKLD3 offers open-drain flexibility for bidirectional reset interfaces but requires an external pullup; versus TPS3808G15DBVR, it provides true dual-rail supervision and RSTIN expandability at the cost of higher unit price and slightly larger footprint.

Availability

MAX6738XKLD3 is available at Aetrix Electronics and suitable for portable/battery-powered equipment, multivoltage systems, and notebook computer subsystems requiring stable component supply and long-term industrial temperature support.

Supply support for MAX6738XKLD3 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, communications, and consumer applications.

The MAX6736–MAX6745 family was designed specifically for low-power, space-constrained multivoltage systems-emphasizing ultra-low quiescent current, factory-trimmed accuracy, and flexible reset configuration across portable, computing, and instrumentation markets.

FAQ

What is the function of the RSTIN pin on the MAX6738XKLD3?

The RSTIN pin on the MAX6738XKLD3 is an adjustable reset threshold input referenced to an internal 0.488V comparator. When the voltage at RSTIN falls below this threshold, the device asserts the open-drain RESET output low. It enables monitoring of a third supply voltage-such as a battery or auxiliary rail-using an external resistor divider network. The MAX6738XKLD3 datasheet specifies RSTIN threshold tolerance as ±1.6% over -40°C to +85°C.

Does the MAX6738XKLD3 require external pullup resistors?

Yes, the MAX6738XKLD3 requires an external pullup resistor on the open-drain RESET pin to ensure proper logic-high deassertion. The MR pin has an internal 1.5kΩ pullup to VCC1 and does not require an external resistor. No pullup is needed for VCC1 or VCC2 inputs. The RESET pullup value is typically 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements.

What are the exact reset threshold voltages for MAX6738XKLD3?

The MAX6738XKLD3 has two factory-trimmed reset thresholds: VTH1 = 4.625V for VCC1 (I/O supply) and VTH2 = 3.075V for VCC2 (core supply), both specified with ±1.5% tolerance over -40°C to +85°C. Its RSTIN input uses a fixed 0.488V internal reference (±1.6%), allowing external monitoring of voltages down to ~0.5V via resistor division. These values are confirmed in Tables 1 and 2 of the MAX6736–MAX6745 datasheet.

Can the MAX6738XKLD3 be used in automotive applications?

The MAX6738XKLD3 is rated for -40°C to +85°C operation and meets industrial temperature requirements, but it is not AEC-Q200 qualified or specified for under-hood automotive use. It is suitable for infotainment head units, telematics modules, or GPS receivers located in climate-controlled cabin environments. For engine bay or safety-critical applications, designers should select AEC-Q100-qualified alternatives.

How does the manual reset (MR) function interact with the power-on reset timeout?

The MR input on the MAX6738XKLD3 operates independently of the VCC reset timeout: pulling MR low for ≥1µs forces RESET low immediately, and RESET remains low for the full 150ms (D3) timeout period after MR returns high-even if VCC1 and VCC2 remain valid. This ensures reliable manual recovery without interference from ongoing power-supply monitoring logic.