Diodes Incorporated ZSM330GTA

Overview

ZSM330GTA from Zetex Semiconductors is a 3-terminal under-voltage monitor IC for microprocessor power-on reset and brown-out detection, featuring a fixed 3.1 V threshold, 20 mV hysteresis, open-collector output sinking ≥10 mA, and guaranteed operation from 1.0 V to 6.5 V supply. It integrates a precision voltage reference and comparator with internal clamp diode, housed in SOT223 package.

For engineers reviewing the ZSM330GTA datasheet, ZSM330GTA pinout, ZSM330GTA application, or ZSM330GTA equivalent, key selection criteria include threshold accuracy over temperature (±0.04 V), low quiescent current (120–180 µA at 3.3 V), propagation delay (2.2 µs), output sink capability at low Vcc (0.25 V @ 0.1 mA, Vcc = 1.0 V), and TO92/SOT223 package compatibility.

Technical Context

The ZSM330GTA implements a bandgap-referenced comparator with built-in hysteresis to reject supply noise and prevent chatter during slow-rising or dipping rails. Its internal clamp diode enables direct connection to RC delay networks for programmable reset timing without external components.

Operation is defined by two thresholds: VIH = 3.01–3.15 V (rising edge) and VIL = 3.01–3.15 V (falling edge), yielding 10–50 mV hysteresis. Output remains low below 1.0 V and asserts low again if Vcc drops below VIL after initial power-up, providing robust brown-out protection.

Key Specifications

Pinout & Package

SOT223 package (suffix G), 4-pin configuration with Pin 4 internally floating or connected to Pin 2 (ground). Standard pinout: Pin 1 = Vcc, Pin 2 = GND, Pin 3 = Open-collector output, Pin 4 = GND (thermal pad).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3+T and TLV803EB31DBZR, the ZSM330GTA uniquely combines internal clamp diode functionality, 10 mA sink drive, and validated -40°C to +85°C performance in a thermally enhanced SOT223 - making it optimal for cost-sensitive, timing-critical, and thermally demanding reset applications.

Availability

ZSM330GTA is available at Aetrix Electronics and suitable for microprocessor systems, battery-powered instrumentation, and automotive body control modules requiring stable component supply and long-term industrial availability.

Supply support for ZSM330GTA 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 (now part of Diodes Incorporated) specialized in high-performance analog and power management ICs, with emphasis on reliability, precision, and thermal efficiency for industrial and automotive markets.

The ZSM330 belongs to Zetex's supply monitoring product line, designed specifically for deterministic power-on reset and brown-out protection in resource-constrained embedded systems without external timing components.

FAQ

What is the minimum supply voltage required for ZSM330GTA to assert a valid reset?

The ZSM330GTA begins asserting low output at supply voltages as low as 1.0 V and maintains it until Vcc rises above the upper threshold (3.01–3.15 V). This ensures reset remains active during ultra-low-voltage start-up sequences, such as cold-cranking or depleted battery conditions, before stable operation is achieved.

Can ZSM330GTA be used with a 5 V microcontroller system?

Yes - the ZSM330GTA operates up to 6.5 V and its open-collector output can interface to 5 V logic via an external pull-up resistor. The 3.1 V threshold remains appropriate for detecting brown-out in 5 V systems powered by regulated 5 V supplies that may sag below 4.5 V under load.

How does the internal clamp diode affect reset timing design?

The internal clamp diode automatically discharges the external timing capacitor when Vcc falls below threshold, eliminating the need for a separate discharge transistor or diode. This simplifies RC-based delay circuits and improves repeatability across temperature and unit-to-unit variation.

Is ZSM330GTA pin-compatible with ZSM330C (TO92 version)?

No - ZSM330GTA uses SOT223 (4-pin, thermal pad) while ZSM330C uses TO92 (3-pin, axial lead). Though functionally identical, their footprints, thermal paths, and pin assignments differ; PCB layout and assembly processes must be adapted for each package variant.