Analog Devices Inc./Maxim Integrated MAX6306UK29D3+T

Overview

The MAX6306UK29D3+T from Maxim Integrated is a 5-pin SOT23 programmable microprocessor supervisory circuit with factory-set 2.9V V_CC reset threshold, 140ms minimum reset timeout, and manual-reset input. It monitors V_CC for undervoltage conditions, asserts an active-low push/pull RESET output, and guarantees valid reset down to V_CC = 1V - ideal for 3.3V embedded systems requiring robust brownout protection.

For engineers reviewing the MAX6306UK29D3+T datasheet, MAX6306UK29D3+T pinout, MAX6306UK29D3+T application, or MAX6306UK29D3+T equivalent, key selection criteria include its 2.9V ±2.5% threshold tolerance over -40°C to +85°C, 8µA supply current, immunity to fast V_CC transients, integrated MR pull-up resistor (63.5kΩ), and compatibility with bidirectional µP reset pins via push/pull drive.

Technical Context

The MAX6306UK29D3+T uses an internal factory-trimmed voltage divider to monitor V_CC against a precise 2.9V threshold, with ±2.5% accuracy over temperature. Its reset generator includes a programmable 140ms minimum timeout (D3 variant) and guarantees RESET assertion while V_CC < 2.9V × 0.975 and deassertion only after V_CC exceeds 2.9V × 1.025 for ≥140ms.

This device integrates a manual-reset input (MR) with TTL/CMOS-compatible logic thresholds, internal 63.5kΩ pull-up, and 1.5µs minimum pulse width requirement. It features push/pull RESET output capable of sinking 3.2mA at V_CC > 4.25V and sourcing 800µA, eliminating external pull-up components in most µP interfaces.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (U5+1), RoHS-compliant lead-free, surface-mount compatible with standard 0.95mm pitch footprint (land pattern 90-0174).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6306UK29D3+T, the leaded MAX6306UK29D3-T offers identical electrical behavior but violates modern environmental directives, while the TPS3808G33DBVR trades manual reset and push/pull drive for lower quiescent current - making MAX6306UK29D3+T optimal for cost-sensitive, RoHS-compliant designs needing integrated reset control.

Availability

The MAX6306UK29D3+T is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, automotive body controllers, and networking edge routers requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6306UK29D3+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 analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.

The MAX6305–MAX6313 family was designed specifically for multivoltage microprocessor supervision in space-constrained, low-power systems - delivering precision reset control with minimal external components and robust transient immunity.

FAQ

What is the exact factory-set reset threshold voltage for MAX6306UK29D3+T?

The MAX6306UK29D3+T has a nominal V_CC reset threshold of 2.9V, with ±2.5% tolerance over the full operating temperature range (-40°C to +85°C). This value is factory-trimmed using an internal resistor divider and corresponds to entry "29" in Table 1 of the datasheet, where 29 = 2.93V nominal (rounded to 2.9V in part numbering). The MAX6306UK29D3+T guarantees reset assertion when V_CC falls below 2.9V × 0.975 and release only after V_CC exceeds 2.9V × 1.025 for ≥140ms.

Does MAX6306UK29D3+T support manual reset functionality, and how is it implemented?

Yes, the MAX6306UK29D3+T includes a dedicated MR (manual reset) input on pin 4. A logic-low pulse ≥1.5µs on this pin forces the RESET output low for the full 140ms timeout period, regardless of V_CC status. The pin features an internal 63.5kΩ pull-up resistor, allowing it to be left unconnected or tied to V_CC when unused. For implementation, connect a normally open momentary switch between MR and GND - no external debounce components are needed due to the device's built-in glitch rejection.

What is the output structure of the RESET pin on MAX6306UK29D3+T, and why does it matter?

The RESET pin on MAX6306UK29D3+T is an active-low push/pull output - meaning it actively drives low (sinking up to 3.2mA) and actively drives high (sourcing up to 800µA). This eliminates the need for an external pull-up resistor, simplifies µP interface design, and ensures fast, well-defined edges during reset assertion/deassertion. Unlike open-drain alternatives, the push/pull structure guarantees valid logic levels even under heavy capacitive loads or noisy environments, making MAX6306UK29D3+T suitable for direct connection to bidirectional reset pins like those found on ARM Cortex-M or Renesas RL78 microcontrollers.

Can MAX6306UK29D3+T monitor voltages other than V_CC?

Yes, the MAX6306UK29D3+T includes an adjustable RST IN input (pin 3) that can monitor a secondary supply rail using an external resistor divider. By connecting R1 and R2 between the target voltage (VIN) and GND, with RST IN at their junction, the device triggers reset when VIN falls below a user-defined threshold calculated as V_TH = (R1 + R2)/R2 × 1.23V. This allows independent supervision of auxiliary rails such as 1.8V sensor supplies or 5V analog domains while the primary V_CC threshold remains fixed at 2.9V - a capability confirmed in the Pin Description and Adjustable Reset Inputs sections of the MAX6306UK29D3+T datasheet.

What is the minimum V_CC voltage at which MAX6306UK29D3+T guarantees valid RESET output operation?

The MAX6306UK29D3+T guarantees valid RESET output operation down to V_CC = 1V. Below this voltage, the push/pull driver's current sourcing/sinking capability degrades significantly, and the output may become indeterminate. This specification ensures deterministic µP behavior during deep brownout events - for example, when a 3.3V system experiences severe line sag or battery depletion. The MAX6306UK29D3+T maintains active-low reset assertion until V_CC recovers above the 2.9V threshold window, then holds reset for the full 140ms timeout before releasing, providing robust protection even in marginal power conditions.