Diodes Incorporated ZSH330C

Overview

ZSH330C from Zetex Semiconductors (now Diodes Incorporated) is a three-terminal under-voltage monitor IC for microprocessor power-on reset and brownout detection. It features a fixed 3.1 V threshold, 20 mV hysteresis, open-collector output capable of sourcing ≥10 mA, guaranteed operation from 1.0 V to 6.5 V supply, and internal clamp diode for delay capacitor discharge - deployed in embedded controllers and battery-powered instrumentation.

For engineers reviewing the ZSH330C datasheet, ZSH330C pinout, ZSH330C application, or ZSH330C equivalent, key selection considerations include its precise 3.1 V trip point for 3.3 V logic systems, low quiescent current (130–180 µA), TO92 package compatibility, and open-collector interface requiring only one external pull-up resistor.

Technical Context

The ZSH330C integrates a precision bandgap voltage reference and comparator with built-in hysteresis to eliminate oscillation near the threshold. Its output remains high during power-up until V_CC exceeds 3.09 V (typ.), then transitions low; on falling V_CC, it reasserts high below 3.07 V (typ.), delivering clean reset assertion without external timing components.

It operates across –40°C to +85°C with threshold drift ≤±10 mV over temperature and supports reset delay generation via external R–C network (TDY = R·C_d·ln[(V_IN−V_TH)/(V_IN−V_SAT)]) - enabling configurable reset hold time for diverse MCU boot requirements.

Key Specifications

Pinout & Package

Package: TO92 (suffix C), through-hole mounting; pin 1 = V_CC, pin 2 = GND, pin 3 = Output (open-collector).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809SCSA+ and TPS3808G01DBVR, the ZSH330C offers lowest BOM cost for fixed 3.1 V reset in TO92 layouts, retains analog simplicity with integrated clamp diode, and delivers fastest propagation delay - ideal for cost-sensitive, space-tolerant industrial controls.

Availability

ZSH330C is available at Aetrix Electronics and suitable for microprocessor reset, battery-powered instrumentation, and industrial control panels requiring stable component supply with long-term obsolescence management.

Supply support for ZSH330C 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 power management ICs for industrial and automotive markets.

The ZSH330 series was designed specifically for robust, low-cost power-supply monitoring in resource-constrained embedded systems - emphasizing accuracy, hysteresis stability, and ease of integration without external passive tuning.

FAQ

What is the function of the internal clamp diode in the ZSH330C?

The internal clamp diode discharges the external timing capacitor (C_d) when the output transitions from low to high. This eliminates the need for an external diode in RC-based delayed reset circuits, reducing component count and improving reliability in battery-operated equipment where leakage paths must be minimized.

Can the ZSH330C be used with a 5 V supply?

Yes - the ZSH330C operates across 1.0 V to 6.5 V input range. At 5 V, its 3.1 V threshold still provides valid reset assertion for 3.3 V logic domains powered from the same rail, and its output saturation voltage remains below 0.4 V at 2 µA load, ensuring clean logic-level compatibility.

Why does the ZSH330C specify both rising and falling threshold voltages?

Rising (V_IL) and falling (V_IH) thresholds define hysteresis - 3.09 V (typ.) for release and 3.07 V (typ.) for reassertion. This 20 mV gap prevents output oscillation during slow or noisy supply transients, ensuring single, clean reset pulses even under marginal power conditions.

Is the ZSH330C pin-compatible with the ZSH330G?

No - ZSH330C uses TO92 (3-pin, V_CC/GND/OUT), while ZSH330G uses SOT223 (4-pin, with exposed thermal pad tied to GND). Pin 4 on ZSH330G is electrically isolated or connected to pin 2; layout and footprint differ significantly, requiring separate PCB designs for each variant.