Analog Devices Inc./Maxim Integrated MAX6355SVUT

Overview

MAX6355SVUT from Maxim Integrated is a dual-voltage microprocessor supervisory IC with open-drain active-low reset output, designed to monitor VCC1 and VCC2 supply rails and a third voltage via RSTIN input. It features factory-set thresholds of 2.93V (VCC1) and 1.58V (VCC2), 20µA supply current, 100ms min reset pulse width, and operates over –40°C to +85°C. Used in multivoltage embedded systems requiring reliable power-on and brownout detection.

For engineers reviewing the MAX6355SVUT datasheet, MAX6355SVUT pinout, MAX6355SVUT application, or MAX6355SVUT equivalent, key selection criteria include its open-drain RST output referenced to VCC1, RSTIN threshold of 1.22V for third-voltage monitoring, guaranteed RESET validity down to VCC1 = 1V or VCC2 = 1V, and compatibility with low-power portable/battery-powered equipment.

Technical Context

The MAX6355SVUT implements independent precision voltage comparators for VCC1 and VCC2, asserting reset when either drops below its respective threshold (2.93V/1.58V). Its RSTIN pin provides an adjustable third-voltage monitor with a fixed 1.22V internal reference, enabling external resistive divider configuration.

It uses an open-drain RST output referenced to VCC1, requiring an external pull-up resistor, and includes a debounced TTL/CMOS-compatible manual reset (MR) input. The device guarantees functional reset assertion as long as either VCC1 ≥ 1.0V or VCC2 ≥ 1.0V - critical for low-voltage brownout recovery scenarios.

Key Specifications

Pinout & Package

MAX6355SVUT is housed in a 6-pin SOT23-6 package with 1.6mm × 2.9mm footprint and 0.95mm height, suitable for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6356SVUT, MAX6355SVUT offers open-drain flexibility for shared reset busses and lower leakage in high-impedance configurations; compared with TPS3808G33, it delivers integrated dual-rail supervision and RSTIN-based third-voltage monitoring - eliminating BOM cost and board area for discrete solutions.

Availability

MAX6355SVUT is available at Aetrix Electronics and suitable for industrial control systems, portable medical devices, automotive body electronics, and smart metering applications requiring stable component supply and long-term lifecycle support.

Supply support for MAX6355SVUT 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 and mixed-signal ICs for industrial, automotive, communications, and computing markets.

The MAX6351–MAX6360 family was developed specifically for multivoltage microprocessor systems needing simultaneous, independent supervision of two or three supply rails with minimal external components.

FAQ

What is the function of the RSTIN pin on the MAX6355SVUT?

The RSTIN pin on the MAX6355SVUT serves as an adjustable third-voltage monitor input with a fixed internal reference of 1.22V. When an external voltage applied to RSTIN falls below this threshold, the device asserts the RST output. To monitor voltages higher than 1.22V, a resistive divider must be used between the target supply and RSTIN. This feature allows the MAX6355SVUT to supervise three distinct rails - VCC1, VCC2, and a third voltage - making it ideal for complex multivoltage systems without adding extra ICs.

Does the MAX6355SVUT provide watchdog timer functionality?

No, the MAX6355SVUT does not include a watchdog timer. Watchdog functionality is exclusive to the MAX6358/MAX6359/MAX6360 variants in the same family. The MAX6355SVUT is specifically configured for dual-voltage supervision plus third-voltage monitoring via RSTIN, with no WDI pin or associated timeout circuitry. If watchdog capability is required, engineers should select MAX6358SVUT, MAX6359SVUT, or MAX6360SVUT instead - all of which share identical VCC1/VCC2 thresholds and RSTIN functionality but add the 46.4s startup and 2.9s normal watchdog timeout modes.

What is the recommended pull-up resistor value for the RST output of the MAX6355SVUT?

The MAX6355SVUT features an open-drain RST output, requiring an external pull-up resistor. For standard CMOS µP interfaces operating at VCC1 = 3.3V, a 10kΩ pull-up to VCC1 is recommended to ensure fast rise time (<1µs) and adequate noise margin. At VCC1 = 5.0V, values up to 47kΩ remain acceptable for low-power applications. The device guarantees VOL ≤ 0.3V at ISINK = 50µA over temperature, so the selected resistor must limit sink current to within this specification while maintaining sufficient voltage level for the driven load. Always verify timing margins with actual load capacitance in final layout.

Can the MAX6355SVUT operate with VCC1 and VCC2 supplied from different voltage sources?

Yes, the MAX6355SVUT is explicitly designed to operate with VCC1 and VCC2 sourced from independent power rails - for example, +3.3V and +1.8V - and will assert RST if either drops below its factory-set threshold (2.93V and 1.58V respectively). The device remains functional as long as at least one supply is ≥ 1.0V, and its internal architecture isolates the two monitoring paths. This independence enables robust supervision in systems with asynchronous power sequencing, such as FPGAs with separate core/I/O supplies or SoCs with multiple domain regulators - all without cross-coupling or shared reference dependencies.

How does the MAX6355SVUT handle power supply transients?

The MAX6355SVUT incorporates built-in transient immunity: it ignores negative-going VCC1 and VCC2 transients shorter than ~100ns (at 100mV overdrive), as verified in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph. This filtering prevents false resets caused by switching noise or brief dips during load transients. The reset delay is also tightly controlled - typically 20µs - ensuring predictable timing behavior. Combined with 20ppm/°C tempco on reset thresholds and guaranteed hysteresis, the MAX6355SVUT maintains reliable supervision even in electrically noisy environments like motor drives or RF modules where supply rail integrity cannot be assumed.