Diodes Incorporated ZXSC300E5TA

Overview

ZXSC300E5TA from Zetex Semiconductors is a PFM-based LED driver controller IC designed for single- or multi-cell white LED applications powered by 0.8–8 V sources (e.g., 1.2 V NiMH, 1.5 V alkaline). It delivers fixed-output constant-current pulses via external switching transistor control, achieves 94% efficiency at 1.5 V input, and operates down to 0.8 V startup voltage. Used with FMMT617 NPN and ZHCS1000 Schottky diode, it enables compact boost converters for flashlight and backlight systems.

For engineers reviewing the ZXSC300E5TA datasheet, ZXSC300E5TA pinout, ZXSC300E5TA application, or ZXSC300E5TA equivalent, key selection criteria include minimum operating voltage (0.8 V), ISENSE threshold (19 mV), VDRIVE output capability (−0.5 mA high-side drive), quiescent current (0.2 mA), and SOT23-5 package compatibility with discrete power stage components.

Technical Context

The ZXSC300E5TA implements a pulse-frequency modulation (PFM) architecture where output current is regulated by comparing voltage across an external sense resistor to an internal 19 mV reference. A monostable circuit enforces a fixed 1.7 µs discharge time (TOFF) to ensure inductor reset before next cycle.

Its VDRIVE pin supplies dynamic base drive current (1.5–3.6 mA) to an external NPN transistor (e.g., FMMT617), enabling fast turn-off (<30 ns) and low conduction loss. Operating frequency is load- and input-dependent-typically ~200 kHz under nominal conditions-but varies with input voltage, LED forward voltage, and programmed peak current.

Key Specifications

Pinout & Package

SOT23-5 surface-mount package (JEDEC MO-178AA); 3.0 × 2.5 mm footprint, 1.1 mm max height; lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED driver controller applications.

Compared with MAX1910EUT+T and TPS61060DRCR, the ZXSC300E5TA uniquely supports sub-1 V operation with discrete NPN control, delivering highest efficiency in ultra-low-voltage, cost-sensitive LED flashlights and solar lights where external transistor selection (e.g., FMMT617) enables fine-tuned trade-offs between saturation loss and gain.

Availability

ZXSC300E5TA is available at Aetrix Electronics and suitable for LED flashlights, solar-powered path lights, and industrial panel indicators requiring stable component supply across extended temperature ranges and low-voltage battery chemistries.

Supply support for ZXSC300E5TA 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) is a UK-based designer of high-performance analog and power semiconductors, ISO 9001/TS16949 certified, with focus on efficiency-critical discrete and controller solutions.

The ZXSC300 belongs to Zetex's low-voltage LED driver controller product line, engineered specifically for cost-optimized, high-efficiency boost conversion from single primary or rechargeable cells in portable lighting and instrumentation.

FAQ

What external components are mandatory for ZXSC300E5TA operation?

The ZXSC300E5TA requires three mandatory external components: an NPN switching transistor (e.g., FMMT617), a current-sense resistor connected to ISENSE, and an inductor (e.g., 100 µH). A Schottky diode (e.g., ZHCS1000) is required only in rectified-output configurations; pulsed-output designs omit it. No input/output capacitors are strictly mandatory but recommended for EMC and ripple control.

Can ZXSC300E5TA drive multiple LEDs in series?

Yes - the ZXSC300E5TA regulates current, not voltage, so it can drive series-connected white LEDs as long as the total forward voltage remains within the boost converter's capability (determined by input voltage, inductor value, and peak current). With a 1.5 V input and 100 µH inductor, up to three 3.2 V white LEDs are supported in typical reference designs.

How is output current set, and what tolerance applies?

Output current is set by the ISENSE sense resistor: ILED = 19 mV / RSENSE. The ISENSE threshold has a typical value of 19 mV with ±5 mV variation across temperature and unit-to-unit, resulting in ±26% current tolerance unless trimmed. For tighter regulation, use precision resistors and consider temperature-compensated layouts.

Is ZXSC300E5TA suitable for automotive applications?

No - while it operates from −40°C to +85°C, the ZXSC300E5TA lacks AEC-Q100 qualification, has no built-in watchdog or fault reporting, and its 10 V absolute maximum supply rating falls short of automotive load-dump requirements. It is intended for consumer, industrial, and solar-powered portable equipment-not automotive subsystems.