Analog Devices Inc./Maxim Integrated MAX709SESA+T

Overview

MAX709SESA+T from Maxim Integrated is a precision power-supply monitor IC with active-low reset output, designed for +3V systems requiring reliable brownout detection and 140ms minimum power-on reset delay. It features a 2.93V nominal reset threshold, operates down to 1V supply, consumes only 35µA typical supply current, and is housed in an 8-pin SO package. It ensures microprocessor reset integrity during power-up, power-down, and transient voltage sags.

For engineers reviewing the MAX709SESA+T datasheet, MAX709SESA+T pinout, MAX709SESA+T application, or MAX709SESA+T equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), immunity to short VCC transients (<40µs at 100mV overdrive), guaranteed RESET state down to VCC = 1V, and compatibility with 3V/3.3V/5V logic interfaces without external components.

Technical Context

The MAX709SESA+T integrates a precision voltage reference, comparator, and reset timer circuit to assert RESET low when VCC drops below 2.93V (±1.5%) and hold it active for ≥140ms after VCC recovers above threshold. Its internal architecture eliminates trimming components and supports operation across -40°C to +85°C.

It uses a dedicated open-drain RESET output capable of sinking 1.2mA at VCC = reset threshold min, with guaranteed logic-low voltage ≤0.4V at 100µA sink load. The device exhibits <100µs power-down reset delay and maintains stable reset threshold over temperature (±0.3% typical drift).

Key Specifications

Pinout & Package

MAX709SESA+T is supplied in an 8-pin SO (Small Outline) package, 150mil width, lead-free (RoHS-compliant) with +T suffix indicating tape-and-reel packaging.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-supply monitor applications.

Compared with MAX709SESA+T, MAX706RSESA+T offers earlier reset assertion for lower-voltage rails but reduces noise margin, while TPS3808G33DBVR trades package size and adjustability for reduced transient resilience and non-drop-in layout compatibility.

Availability

MAX709SESA+T is available at Aetrix Electronics and suitable for industrial control systems, medical handheld devices, and automotive body electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX709SESA+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 high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and computing markets.

The MAX709 belongs to Maxim's µP supervisory circuit family, engineered specifically to replace discrete reset solutions in cost-sensitive, space-constrained embedded systems requiring guaranteed power-on and brownout reset behavior.

FAQ

What is the exact reset threshold voltage of the MAX709SESA+T?

The MAX709SESA+T has a nominal reset threshold voltage of 2.93V, with a guaranteed tolerance of ±1.5% over the full operating temperature range (-40°C to +85°C). This value is laser-trimmed at wafer test and confirmed in the Electrical Characteristics table of the official datasheet. The 'S' suffix in MAX709SESA+T explicitly denotes the 2.93V version, distinguishing it from other variants like MAX709RESA+T (2.63V) or MAX709LESA+T (4.65V).

Does the MAX709SESA+T require external components to function?

No, the MAX709SESA+T requires no external resistors, capacitors, or trimming components to perform its core reset supervision function. It integrates a precision voltage reference, comparator, and reset timer. A 0.1µF ceramic bypass capacitor is recommended at the VCC pin for noise immunity, but this is a standard decoupling practice-not a functional requirement for basic operation. The RESET output is open-drain and needs only an external pull-up resistor to interface with most µP reset inputs.

Can the MAX709SESA+T operate reliably below 3.0V supply?

Yes, the MAX709SESA+T is fully specified to operate down to VCC = 1.0V. Its RESET output remains valid (guaranteed low or high-impedance) across this entire range, and the reset comparator continues to monitor VCC relative to the 2.93V threshold even as VCC falls. At VCC < 1.0V, RESET becomes high-impedance, but this condition is outside the guaranteed operating range and aligns with system shutdown behavior in most 3V designs.

Is the MAX709SESA+T pin-compatible with other MAX709 variants?

Yes, all MAX709 variants-including MAX709SESA+T, MAX709RESA+T, and MAX709LESA+T-share identical 8-pin SO package dimensions, pinout, and electrical interface. The only functional difference is the factory-trimmed reset threshold voltage. No PCB layout changes are needed when substituting between S, R, L, M, or T suffix versions, making them drop-in replacements for threshold tuning during design validation or production ramp.

What is the maximum transient duration the MAX709SESA+T can ignore without asserting reset?

The MAX709SESA+T can ignore negative-going VCC transients up to 40µs in duration when the transient magnitude is 100mV below its 2.93V reset threshold (i.e., VCC dips to 2.83V). This immunity is characterized per Figure 1 in the datasheet and applies across the full temperature range. For deeper transients (e.g., 200mV overdrive), the allowable pulse width decreases proportionally, maintaining robust operation in electrically noisy environments such as motor-driven industrial equipment.