Analog Devices Inc./Maxim Integrated MAX6340UK26+T

Overview

MAX6340UK26+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.625V ±2.5% factory-trimmed reset threshold, capacitor-adjustable reset timeout (275µs to 5.75ms), and guaranteed operation down to VCC = 1V. It monitors supply voltage in battery-powered embedded controllers and portable equipment to prevent code-execution errors during brownout.

For engineers reviewing the MAX6340UK26+T datasheet, MAX6340UK26+T pinout, MAX6340UK26+T application, or MAX6340UK26+T equivalent, key selection factors include its SOT23-5 open-drain reset output, 1.6µA typical quiescent current, -40°C to +125°C operating range, and compatibility with external pullup voltages up to 5.5V.

Technical Context

The MAX6340UK26+T implements a precision voltage-detection circuit using laser-trimmed resistors to set its 2.625V reset threshold with ±2.5% accuracy over temperature. Its reset assertion logic responds to VCC falling below threshold with 80µs propagation delay and holds reset asserted for a timeout period determined by an external capacitor on the SRT pin.

A 240nA internal ramp current charges the SRT capacitor to a 0.65V internal reference; deassertion occurs when that voltage is reached. The open-drain RESET output requires an external pullup and remains valid for VCC ≥ 1V, supporting logic-level translation across mixed-voltage systems.

Key Specifications

Pinout & Package

MAX6340UK26+T is housed in a 5-pin SOT23-5 package with exposed pad (RoHS-compliant lead-free). Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is N.C. (not internally connected), Pin 4 is VCC, and Pin 5 is RESET (open-drain active-low output).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3470ASX-26 and NCP302LSN26T1G, the MAX6340UK26+T uniquely combines ultra-low 1.6µA supply current, guaranteed reset validity down to VCC = 1V, and open-drain output-making it optimal for battery longevity, deep brownout resilience, and flexible reset bus architectures.

Availability

MAX6340UK26+T is available at Aetrix Electronics and suitable for battery-powered portable equipment, automotive body electronics, and medical patient monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6340UK26+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

Analog Devices is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The MAX6340 series belongs to Analog Devices' microprocessor supervisor product line, engineered for ultra-low-power, high-accuracy voltage monitoring in safety-critical and energy-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6340UK26+T?

The MAX6340UK26+T features a factory-laser-trimmed reset threshold of 2.625V with ±2.5% accuracy over the full -40°C to +125°C temperature range. This value is confirmed in Table 1 of the datasheet, where suffix "26" corresponds to nominal 2.625V, and electrical characteristics specify VTH = 2.559V (min) to 2.691V (max) at TA = -40°C to +125°C. The MAX6340UK26+T maintains this precision without external calibration.

Does the MAX6340UK26+T support wired-OR reset functionality?

Yes, the MAX6340UK26+T supports wired-OR reset because its RESET pin is an open-drain active-low output. This allows multiple supervisors or auxiliary logic signals (e.g., watchdog timeout, thermal shutdown) to share a common reset bus by connecting their open-drain outputs together with a single pullup resistor. The MAX6340UK26+T will assert low when its VCC falls below 2.625V, and release high only after the capacitor-adjustable timeout expires-enabling coordinated system reset.

What capacitor value is required to achieve a 4.375ms reset timeout with the MAX6340UK26+T?

To achieve a 4.375ms reset timeout with the MAX6340UK26+T, a 1500pF capacitor must be connected between the SRT pin and GND. This value is explicitly validated in the Electrical Characteristics table under "Reset Timeout Period (tRP)" with CSRT = 1500pF yielding tRP = 4.375ms (typ). The relationship is linear: tRP = (2.73 × 10⁶ × CSRT) + 275µs, so CSRT = (tRP − 275µs) / 2.73 × 10⁶ yields 1500pF for 4.375ms.

Can the MAX6340UK26+T operate reliably when VCC drops to 1.0V?

Yes, the MAX6340UK26+T guarantees valid RESET output behavior down to VCC = 1.0V, as stated in the Benefits and Features section and confirmed in Absolute Maximum Ratings and Electrical Characteristics. At VCC = 1.0V, the device continues to assert RESET correctly when VCC falls below 2.625V and maintains output drive capability (VOL ≤ 0.3V at ISINK = 50µA). This ensures deterministic reset during deep brownout-critical for medical and automotive applications.

Is the MAX6340UK26+T pin-compatible with other reset supervisors in the same family?

Yes, the MAX6340UK26+T is pin-compatible with other 5-pin SOT23-5 variants in the MAX6340/MAX6424–MAX6426 family, including MAX6424UK26+T and MAX6425UK26+T. All share identical pinout: Pin 1 = SRT, Pin 2 = GND, Pin 3 = N.C., Pin 4 = VCC, Pin 5 = RESET. However, output type differs-MAX6340UK26+T and MAX6425UK26+T use open-drain RESET, while MAX6424UK26+T uses push-pull-so direct substitution requires verifying reset topology compatibility.