Analog Devices Inc./Maxim Integrated MAX6724UTSYD3+

Overview

MAX6724UTSYD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and RSTIN (adjustable down to 0.626V) with 210ms minimum reset timeout, push-pull active-low RST output, and power-fail input/output capability - used for reliable reset assertion in multivoltage telecom and industrial power systems.

For engineers reviewing the MAX6724UTSYD3+ datasheet, MAX6724UTSYD3+ pinout, MAX6724UTSYD3+ application, or MAX6724UTSYD3+ equivalent, key selection criteria include dual-supply monitoring with factory-trimmed thresholds, externally adjustable third-voltage detection, guaranteed reset validity down to VCC = 0.8V, and integrated PFI/PFO for early power-fail warning in battery-backed or server-grade power architectures.

Technical Context

The MAX6724UTSYD3+ implements independent voltage comparators for VCC1 and VCC2 with ±1.5% threshold accuracy and 20ppm/°C tempco, plus a high-impedance RSTIN input referenced to a 626.5mV internal bandgap. It asserts reset when any monitored supply falls below its threshold and holds reset for ≥210ms after all supplies recover.

Its power-fail comparator (PFI) uses the same 626.5mV reference and drives an open-drain PFO output with 2µs propagation delay; the push-pull RST output guarantees VOL ≤ 0.4V at ISINK = 3.2mA and VOH ≥ 0.8×VCC1 at ISOURCE = 800µA - enabling direct interface to 1.8V–5.0V µP reset inputs without external level-shifting.

Key Specifications

Pinout & Package

MAX6724UTSYD3+ is housed in a 6-pin SOT23-6 package (1.6mm × 2.9mm × 1.1mm), surface-mount, RoHS-compliant, with gull-wing leads and thermal pad not connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6723UTSYD3+, the MAX6724UTSYD3+ offers direct-drive reset capability eliminating pullup resistors, while TPS3808G33DBVR trades triple-monitoring and PFI/PFO for lower IQ and simpler dual-rail use cases - making MAX6724UTSYD3+ optimal for complex multivoltage systems requiring guaranteed reset integrity and early power-fail signaling.

Availability

MAX6724UTSYD3+ is available at Aetrix Electronics and suitable for telecom power management, industrial PLC power sequencing, and server baseboard management requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX6724UTSYD3+ 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, automotive, and communications applications.

The MAX6715–MAX6729 family delivers compact, ultra-low-power supervisory solutions for multivoltage systems - engineered to replace discrete reset circuits and improve reliability in space-constrained, mission-critical power architectures.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6724UTSYD3+?

The MAX6724UTSYD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with ±1.5% tolerance over temperature and supply voltage. This value is encoded in the "SY" suffix per Maxim's Reset Voltage Threshold Suffix Guide and is verified across -40°C to +85°C. The MAX6724UTSYD3+ uses this threshold to detect brownout on primary 5V rails before system instability occurs.

Does the MAX6724UTSYD3+ support monitoring a third voltage, and how is it configured?

Yes, the MAX6724UTSYD3+ supports third-voltage monitoring via the RSTIN pin, which compares the applied voltage against an internal 626.5mV reference. To set a custom threshold (e.g., 1.8V), connect a resistor divider from the target supply to GND with RSTIN at the midpoint - using VEXT_TH = 626.5mV × ((R1 + R2)/R2). The MAX6724UTSYD3+ guarantees RSTIN input current ≤ ±25nA, enabling high-resistance dividers for minimal power draw.

What is the function of the PFI and PFO pins on the MAX6724UTSYD3+?

The PFI (power-fail input) pin is a high-impedance comparator input referenced to 626.5mV; when voltage at PFI drops below this threshold, the PFO (power-fail output) pin asserts low. PFO is open-drain and requires an external pullup. In the MAX6724UTSYD3+, PFO provides sub-2µs response to supply collapse - enabling firmware-triggered data save or interrupt-driven shutdown before full brownout, distinct from the reset timeout behavior of the RST pin.

How does the reset timeout period of 210ms affect system design with the MAX6724UTSYD3+?

The MAX6724UTSYD3+ guarantees a minimum reset timeout of 210ms after all monitored supplies exceed their thresholds, ensuring µPs and peripherals fully stabilize before release. This fixed delay eliminates reliance on external RC timing networks and prevents premature release during marginal power recovery. Designers must verify that their µP's minimum reset pulse width requirement is met - the MAX6724UTSYD3+'s 210ms satisfies all common ARM, x86, and RISC-V processors' specifications.

Is the MAX6724UTSYD3+ compatible with both 3.3V and 5V microprocessor reset inputs?

Yes, the MAX6724UTSYD3+'s push-pull RST output is fully compatible with 3.3V and 5V µP reset inputs: VOH ≥ 0.8×VCC1 at ISOURCE = 800µA (e.g., ≥4.0V at VCC1 = 5V), and VOL ≤ 0.4V at ISINK = 3.2mA. Its guaranteed operation down to VCC1 = 0.8V ensures valid logic levels even during brownout - unlike open-drain alternatives that require external pullups and suffer voltage droop under load. This makes the MAX6724UTSYD3+ ideal for mixed-voltage systems.