Diodes Incorporated ZLDO300T8TA

Overview

ZLDO300T8TA from Diodes Incorporated is an ultra-low-dropout linear regulator delivering a fixed 3.0 V output at up to 300 mA, with 30 mV dropout at 100 mA load, 1 mA typical quiescent current, and integrated low-battery flag (open-collector NPN) that asserts when input falls within 200 mV of output - used in portable instrumentation for early power-fail warning.

For engineers reviewing the ZLDO300T8TA datasheet, ZLDO300T8TA pinout, ZLDO300T8TA application, or ZLDO300T8TA equivalent, key selection criteria include dropout voltage vs. load, shutdown control threshold (1.5 V), low-battery detect accuracy (±0.2 V), output tolerance (±3.3%), and SM8 package thermal performance under 2 W dissipation.

Technical Context

The ZLDO300T8TA employs a precision bandgap reference and error amplifier with external shaping capacitor (10 pF from Pin 8 to Pin 5) to ensure stability across 10 mA–300 mA loads. Its low-dropout architecture uses a PNP pass transistor enabling regulation down to Vin − Vo = 6 mV at 10 mA.

It integrates two independent monitoring functions: a low-battery comparator referenced to V_OUT + 0.2 V (typ), and thermal shutdown activating at 125 °C. Shutdown control (Pin 2) is high-impedance, requiring <10 µA drive current and asserting at V_SHDN ≥ 1.5 V.

Key Specifications

Pinout & Package

The ZLDO300T8TA is housed in the Zetex SM8 surface-mount package (8-pin small-outline), with exposed thermal pad not electrically connected. Pin 6 (D/C) must remain unconnected; Pin 4 (N/C) is internally floating and may be left open or tied to GND without impact.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-dropout linear regulator applications.

Compared with MCP1700T-3002E/MB and TPS76330DBVR, the ZLDO300T8TA uniquely combines 300 mA output, sub-30 mV dropout at 100 mA, integrated LBF, and active-high shutdown - making it the only option among the three capable of autonomous battery-fail response in portable instrumentation.

Availability

ZLDO300T8TA is available at Aetrix Electronics and suitable for portable instrumentation, handheld communications, and laptop subsystem power management requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for ZLDO300T8TA 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

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal devices, with design centers in Asia, Europe, and the US, serving industrial, computing, and consumer markets.

The ZLDO series was developed for space-constrained, battery-powered applications demanding ultra-low dropout, low quiescent current, and integrated power-monitoring features - targeting portable test equipment and handheld communication terminals.

FAQ

What is the minimum input voltage required for regulation at full 300 mA load?

The ZLDO300T8TA maintains regulation as long as Vin ≥ Vout + dropout voltage. At 300 mA, typical dropout is 100 mV, so minimum Vin = 3.0 V + 0.1 V = 3.1 V. Absolute maximum dropout is 200 mV per datasheet, so design margin requires Vin ≥ 3.2 V to guarantee regulation across temperature and process variation.

Can Pin 6 (D/C) be connected to ground to improve thermal performance?

No - Pin 6 is internally connected to a sensitive analog node and must remain unconnected. Connecting it to any potential, including ground, risks instability, oscillation, or permanent device malfunction. The SM8 package thermal path relies solely on the exposed pad (not present in this variant) and PCB copper area under Pins 3, 5, and 7.

How does the low-battery flag behave when the input voltage recovers?

The LBF output releases (goes high-impedance) when Vin rises above Vout + 0.4 V, providing 200 mV hysteresis to prevent chatter near the trip point. No external pull-up is driven by the device - a 10–100 kΩ external resistor to Vout or logic supply is required to generate a clean logic-high signal upon recovery.

Is the 10 pF shaping capacitor (Pin 8 to Pin 5) mandatory for stability?

Yes - the 10 pF capacitor is required for guaranteed stability across all loads (10 mA–300 mA) and temperatures (−40 °C to +85 °C). Reducing it improves AC response but risks oscillation under heavy or dynamic loads; omitting it causes sustained ringing on load transients and violates the SOA limits defined in the datasheet.