Diodes Incorporated ZSH330N8TA

Overview

ZSH330N8TA from Zetex Semiconductors (now Diodes Incorporated) is a three-terminal under-voltage monitor IC for microprocessor power-on reset and brown-out detection in 3.3 V systems. It features a fixed 3.1 V threshold, 20 mV hysteresis, open-collector output sourcing ≥10 mA, guaranteed operation from 1.0 V to 6.5 V supply, and internal clamp diode for RC delay timing.

For engineers reviewing the ZSH330N8TA datasheet, ZSH330N8TA pinout, ZSH330N8TA application, or ZSH330N8TA equivalent, key selection criteria include precise 3.1 V trip point, low quiescent current (180 µA max), SOT223 package compatibility, reset timing predictability via external capacitor, and operation across –40°C to +85°C industrial temperature range.

Technical Context

The ZSH330N8TA integrates a precision bandgap voltage reference, comparator with built-in hysteresis, and open-collector NPN output stage. Its dual-threshold behavior (VIH = 3.07 V typ, VIL = 3.09 V typ) ensures clean reset assertion/deassertion without oscillation during supply ramp-up or brown-out events.

It operates as a standalone supervisory device: output remains high below 1.0 V (power-on reset), transitions low above 3.1 V (normal operation), and reasserts high if supply drops below 3.07 V (brown-out reset). The internal clamp diode enables predictable RC-based reset delay timing without external diodes.

Key Specifications

Pinout & Package

Available in SOT223 (suffix G) and TO92 (suffix C) packages. ZSH330N8TA corresponds to the SOT223 variant with pin 1 = V_CC, pin 2 = GND, pin 3 = OUT, and pin 4 = thermal pad (internally connected to pin 2 or left floating per layout).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV803DBZT and MAX809SEUR+T, ZSH330N8TA uniquely combines integrated clamp diode, 10 mA output drive, and SOT223 thermal capability-making it optimal for cost-sensitive, thermally demanding, or RC-timed reset designs where external component count reduction is critical.

Availability

ZSH330N8TA is available at Aetrix Electronics and suitable for microprocessor reset, battery-powered instrumentation, and industrial PLC I/O modules requiring stable component supply and long-term lifecycle support.

Supply support for ZSH330N8TA 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, acquired by Diodes Incorporated in 2008, specialized in high-performance analog and discrete semiconductors for power management and signal conditioning.

The ZSH330 series was designed specifically for robust, low-cost power-supply supervision in 3.3 V embedded systems-emphasizing thermal resilience, noise immunity, and minimal external component count.

FAQ

What is the function of the internal clamp diode in ZSH330N8TA?

The internal clamp diode discharges the external timing capacitor (C_d) during reset deassertion, enabling precise and repeatable RC-based delay timing without adding an external diode. This reduces BOM count and PCB area while maintaining accuracy across temperature (–40°C to +85°C) and supply voltage (1.0–6.5 V).

Can ZSH330N8TA operate with a 2.5 V supply rail?

No. ZSH330N8TA is specified for 3.3 V systems with a 3.1 V threshold; its VIH/VIL range (3.01–3.15 V) does not overlap with 2.5 V logic. For 2.5 V rails, consider alternatives like the TLV809M25DBZR (2.5 V threshold) or MAX6326XR25D3+T (2.5 V, SOT23).

How is reset delay time calculated for ZSH330N8TA?

Reset delay is set by an external RC network: T_DY = R × C_d × ln[(V_IN − V_TH) / (V_IN − V_SAT)]. V_SAT is output saturation voltage (≈0.4 V at 2 µA), V_TH is 3.1 V, and V_IN is supply voltage-values confirmed in the datasheet's Typical Characteristics section.

Is ZSH330N8TA pin-compatible with ZSH330C (TO92)?

No. ZSH330N8TA uses SOT223 (4-pin, thermal pad), while ZSH330C uses TO92 (3-pin, through-hole). Pin 1–3 functions match (V_CC/GND/OUT), but pin 4 on SOT223 is a thermal pad not present in TO92-requiring separate PCB layout and thermal design.