Diodes Incorporated ZSM560C

Overview

ZSM560C from Zetex Semiconductors is a three-terminal under-voltage monitor IC designed for power-on reset and brownout detection in 5 V microprocessor systems. It features a fixed 4.6 V threshold, 20 mV hysteresis, open-collector output capable of sinking ≥10 mA, and guaranteed operation from 1.0 V to 6.5 V supply. Its TO92 package supports through-hole mounting in space-constrained embedded control applications.

For engineers reviewing the ZSM560C datasheet, ZSM560C pinout, ZSM560C application, or ZSM560C equivalent, key selection considerations include its precise 4.6 V trip point, low 200 µA quiescent current at 5 V, −40°C to +85°C operating range, open-collector interface compatibility, and TO92 mechanical footprint for legacy board designs.

Technical Context

The ZSM560C integrates a precision bandgap voltage reference and a comparator with built-in hysteresis to ensure stable switching between high- and low-threshold states (V_IH = 4.61 V typ., V_IL = 4.59 V typ.). Its internal clamp diode enables direct connection to external delay capacitors for programmable reset timing.

Operation begins at V_CC ≥ 1.0 V; below threshold, the output remains low to assert reset; above threshold, the output floats high (open-collector), requiring only one pull-up resistor. Propagation delay is 1.5 µs typical under standard test conditions (R_L = 10 kΩ).

Key Specifications

Pinout & Package

Package: TO92 (3-pin, through-hole, plastic). Pin configuration confirmed per Zetex Issue 4 datasheet (p. 4-363, bottom view): 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 TLV7031DBVR, the ZSM560C offers proven TO92 fit for legacy repair and prototyping, fixed 4.6 V accuracy without calibration, and robust 10 mA sink drive - ideal where mechanical form factor and simplicity outweigh ultra-low IQ requirements.

Availability

ZSM560C is available at Aetrix Electronics and suitable for microprocessor power-on reset, industrial PLC supervision, automotive body control modules, and battery-powered data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZSM560C 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 (now part of Diodes Incorporated) was a UK-based analog and power semiconductor specialist focused on high-reliability discrete and supervisory ICs for industrial and automotive markets.

The ZSM560 series belongs to Zetex's voltage supervisor product line, engineered specifically for deterministic reset generation in 5 V logic systems where predictable threshold accuracy and hysteresis stability are critical to system boot integrity.

FAQ

What is the function of the internal clamp diode in the ZSM560C?

The internal clamp diode connects between the output pin and ground, enabling direct connection of an external timing capacitor (C_d) to generate a programmable reset delay. When the output goes low, the diode discharges C_d; when high, it blocks reverse current. This eliminates need for an external diode in RC reset circuits, reducing BOM count and PCB area.

Can the ZSM560C operate reliably at 1.0 V supply?

Yes - the ZSM560C is fully specified to operate from V_CC = 1.0 V upward. At voltages below 4.6 V, the output remains actively pulled low to maintain reset assertion. Its internal reference and comparator remain functional down to 1.0 V, ensuring valid reset behavior during initial power ramp-up before the 5 V rail reaches regulation.

Is the ZSM560C pin-compatible with the SOT223-packaged ZSM560G?

No - while electrically identical, ZSM560C (TO92) and ZSM560G (SOT223) have different pinouts and physical footprints. TO92 uses bottom-view pin order (1-V_CC, 2-GND, 3-OUT); SOT223 uses top-view with pin 4 floating or tied to pin 2. They are not mechanically interchangeable without PCB redesign.

Does the ZSM560C require an external pull-up resistor on its output?

Yes - the ZSM560C has an open-collector output. A pull-up resistor to the target logic rail (e.g., 5 V or 3.3 V) is mandatory to establish a defined high state when the device is not asserting reset. Typical values range from 4.7 kΩ to 10 kΩ, balancing rise time and power consumption while ensuring sufficient drive for downstream reset inputs.