Analog Devices Inc./Maxim Integrated MAX6338LUB

Overview

MAX6338LUB from Maxim Integrated is a quad voltage monitor IC designed for multivoltage system supervision, monitoring one adjustable input (IN1), +3.3V (IN2), +2.5V with 5% tolerance (IN3), and another adjustable input (IN4). It delivers 25µA typical supply current, operates from +2.5V to +5.5V, and guarantees accurate trip thresholds across –40°C to +85°C using an internal 1.23V bandgap reference. It supports telecom and industrial power-good signaling.

For engineers reviewing the MAX6338LUB datasheet, MAX6338LUB pinout, MAX6338LUB application, or MAX6338LUB equivalent, key selection criteria include its dual adjustable inputs, factory-trimmed ±5% tolerance on +2.5V monitoring, open-drain active-low outputs with internal 10µA pull-ups, wire-OR capability, and µMAX package compatibility in space-constrained embedded supervisory designs.

Technical Context

The MAX6338LUB integrates four independent comparators, each with dedicated input terminals and open-drain outputs. IN1 and IN4 are auxiliary inputs configured for user-adjustable thresholds via external resistor dividers referenced to the internal 1.23V bandgap; IN2 monitors +3.3V with fixed threshold; IN3 monitors +2.5V at –5% tolerance (2.375V trip point). All comparators feature built-in 0.3% hysteresis and share a common undervoltage lockout circuit that forces all outputs low when VCC drops below 2.5V.

Each output (OUT1–OUT4) is open-drain, internally pulled up to VCC with 10µA current, enabling direct wire-OR connection without external components. The device requires no external timing or biasing elements, and its BiCMOS process ensures stable operation across full temperature range while maintaining low quiescent current.

Key Specifications

Pinout & Package

The MAX6338LUB is housed in a 10-pin µMAX® package (3.0mm × 3.0mm, 0.6mm height), compatible with standard surface-mount assembly processes and high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad voltage monitoring applications.

Compared with MAX6340EUB+ and TPS3307-33DGNR, the MAX6338LUB uniquely supports two user-adjustable inputs while retaining factory-trimmed +3.3V and +2.5V (–5%) monitoring - making it optimal for mixed-standard/custom power architectures requiring minimal component count and no external references.

Availability

MAX6338LUB is available at Aetrix Electronics and suitable for telecommunications infrastructure, industrial PLCs, and embedded edge AI gateways requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to +85°C.

Supply support for MAX6338LUB 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 demanding industrial, communications, and computing applications.

The MAX6338LUB belongs to Maxim's voltage supervisor product line, engineered specifically for multirail power integrity verification in space- and power-constrained embedded systems with mixed standard and custom supply voltages.

FAQ

What voltage rails does the MAX6338LUB monitor by default?

The MAX6338LUB monitors one adjustable input (IN1), +3.3V (IN2), +2.5V with –5% tolerance (IN3), and a second adjustable input (IN4). Unlike fixed-rail variants, it does not preset IN1 or IN4 to standard voltages - those require external resistor dividers to set thresholds based on the internal 1.23V reference. This configuration is confirmed in the Selector Guide and Electrical Characteristics table for MAX6338LUB.

Does the MAX6338LUB require external components to monitor +3.3V and +2.5V?

No, the MAX6338LUB requires no external components to monitor +3.3V and +2.5V. Its IN2 pin is factory-trimmed for +3.3V (3.135V nominal trip), and IN3 is factory-trimmed for +2.5V at –5% tolerance (2.375V trip). These thresholds are internally generated using the 1.23V bandgap reference and precision resistor dividers - eliminating the need for external resistors, references, or capacitors for these two rails.

How do I configure the adjustable inputs (IN1 and IN4) on the MAX6338LUB?

To configure IN1 or IN4, connect an external resistor divider between the supply to be monitored and GND, with the divider midpoint fed to the input pin. Use R1 = R2 × ((V_INTH/1.23) – 1), where V_INTH is the desired trip voltage and R2 is typically 100kΩ. For example, to detect 4.5V, R1 ≈ 265kΩ. This method is explicitly defined in the Applications Information section and Figure 6 of the MAX6338LUB datasheet.

What happens to the outputs of the MAX6338LUB when VCC drops below 2.5V?

When VCC drops below 2.5V, the internal undervoltage lockout (UVLO) circuit activates and forces all four outputs (OUT1–OUT4) low, regardless of input voltage conditions. This behavior is guaranteed down to VCC = 1V and prevents spurious resets or undefined logic states during brownout or power-down sequences - a key reliability feature documented in the Pin Description and Absolute Maximum Ratings sections for MAX6338LUB.

Can the MAX6338LUB outputs be wire-ORed together, and what drives them?

Yes, all four outputs of the MAX6338LUB are open-drain and can be wire-ORed to form a single "power good" or system reset signal. Each output has a weak internal 10µA pull-up to VCC, allowing direct connection to other logic without external pull-ups. External pull-ups to any voltage from 0V to +5.5V are also supported, and internal circuitry blocks current flow from the external pull-up to VCC - a capability verified in the Detailed Description and Pin Description sections for MAX6338LUB.