Diodes Incorporated ZM331643GTA

Overview

ZM331643GTA from Zetex Semiconductors is a three-terminal under-voltage monitor IC for microprocessor power-on reset and brownout detection, featuring a fixed 2.68 V threshold, 60 mV hysteresis, open-collector output capable of sinking ≥10 mA, and guaranteed operation from 1.0 V to 10 V supply. It integrates a precision voltage reference and comparator with internal clamp diode, and is qualified for automotive and battery-powered systems.

For engineers reviewing the ZM331643GTA datasheet, ZM331643GTA pinout, ZM331643GTA application, or ZM331643GTA equivalent, key selection criteria include reset threshold accuracy over temperature (±0.06 V), sink current capability at low V_CC (0.25 V saturation at 0.1 mA), quiescent current (125–190 µA), and SOT223 package thermal performance (2 W dissipation).

Technical Context

The ZM331643GTA implements a bandgap-referenced comparator with built-in hysteresis to eliminate oscillation during slow-rising or noisy supply transitions. Its output remains low until V_CC exceeds 2.71 V (rising threshold) and stays low again if V_CC falls below 2.65 V (falling threshold), delivering clean, glitch-free reset assertion.

It supports time-delayed reset via external RC network connected to the internal clamp diode, enabling programmable delay (T_DY = R·C_d·ln[1/(1−V_TH(MPU)/V_IN)]) without additional components. The device operates across −40 °C to +85 °C with threshold drift ≤ ±20 mV over full temperature range.

Key Specifications

Pinout & Package

SOT223-4 package (suffix G), with Pin 4 internally floating or optionally tied to Pin 2 (V_OUT) for enhanced thermal conduction. Standard 3-pin functional configuration: Pin 1 = V_CC, Pin 2 = V_OUT (open-collector), Pin 3 = GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar under-voltage monitor applications.

Compared with TLV803EB26DPWR and MAX809SEUR+T, the ZM331643GTA offers optimal balance of threshold accuracy (±0.06 V), low-temperature drift, and robust 10 mA sink drive-critical for driving reset lines with capacitive loads in industrial and automotive control units without added buffering.

Availability

ZM331643GTA is available at Aetrix Electronics and suitable for microprocessor reset, battery-powered instrumentation, and automotive body electronics requiring stable component supply with full lifecycle traceability and extended temperature support.

Supply support for ZM331643GTA 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

Zetex Semiconductors plc was a UK-based analog and power semiconductor specialist, acquired by Diodes Incorporated in 2008; its legacy voltage supervisors remain widely deployed in industrial and automotive designs.

The ZM33164 series belongs to Zetex's precision voltage monitoring product line, designed specifically for reliable power-on and brownout reset generation in resource-constrained embedded systems with minimal external components.

FAQ

What is the maximum sink current the ZM331643GTA can deliver at 1.0 V supply?

At V_CC = 1.0 V and I_sink = 0.1 mA, the output saturation voltage is specified at 0.25 V maximum. This confirms the device remains functional and capable of pulling low even during deep brownout conditions well below its 2.68 V threshold, enabling fail-safe reset assertion prior to logic failure.

Can the ZM331643GTA be used with a 5 V microcontroller reset input?

Yes-the open-collector output is compatible with 5 V systems when paired with a 5 V pull-up resistor. The device's absolute maximum off-state output voltage is 12 V, and its leakage current remains below 0.5 µA at 3 V output potential, ensuring safe interface without level-shifting circuitry.

How does the internal clamp diode enable reset delay functionality?

The internal clamp diode connects between V_OUT and GND. When an RC network is attached from V_OUT to V_CC, the diode discharges the capacitor during normal operation. At power-up, the capacitor charges through R, delaying reset release until voltage crosses the microprocessor's internal reset threshold-enabling precise, component-free timing.

Is the SOT223 package thermally rated for continuous 20 mA sink current at 85 °C ambient?

Yes-the SOT223 package has a 2 W power dissipation rating. At 20 mA sink and 0.4 V saturation (typical), power dissipation is 8 mW, well within thermal limits. Derating is unnecessary up to 85 °C ambient, provided PCB copper area meets Zetex's recommended 1-inch² thermal pad layout.