Diodes Incorporated ZLDO285T8TA

Overview

ZLDO285T8TA from Diodes Incorporated is an ultra-low-dropout linear regulator delivering a fixed 2.85 V output with 300 mA maximum load current, 30 mV dropout at 100 mA, and integrated low-battery flag (open-collector LBF) and active-high shutdown control - used in battery-powered logic supplies where input-to-output margin is as low as 300 mV.

For engineers reviewing the ZLDO285T8TA datasheet, ZLDO285T8TA pinout, ZLDO285T8TA application, or ZLDO285T8TA equivalent, key selection criteria include dropout voltage vs. load, quiescent current in active/shutdown modes, LBF threshold accuracy, thermal shutdown behavior, and SM8 package layout compatibility for space-constrained PCBs.

Technical Context

The ZLDO285T8TA employs a precision bandgap reference and error amplifier with external shaping capacitor (10 pF from Pin 8 to Pin 5) to achieve ±2.5% output tolerance and stable regulation across –40°C to +85°C. Its dropout voltage is defined at 100 mV output deviation from nominal, measured with Vin = Vout + 1 V baseline.

It integrates two independent monitoring functions: a low-battery comparator triggering when Vin falls within 200–400 mV of Vout (typ. 300 mV), and thermal shutdown activating at ~125°C die temperature. Shutdown control (Pin 2) draws <10 µA and disables regulation while reducing Iq to 11 µA (typ).

Key Specifications

Pinout & Package

Package: SM8 (Zetex 8-pin small-outline surface-mount), 5.0 mm × 6.2 mm footprint, exposed pad not electrically connected. Requires minimal board area and supports reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2802E/TT and NCP1117ST28T3G, the ZLDO285T8TA uniquely combines sub-50 mV dropout, integrated LBF, and shutdown control in an 8-pin SM8 package - making it the only choice for compact, battery-aware, interrupt-driven embedded systems.

Availability

ZLDO285T8TA is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, and industrial data loggers requiring stable component supply with guaranteed long-term availability and full traceability.

Supply support for ZLDO285T8TA 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 across Asia, Europe, and the US.

The ZLDO series was developed specifically for ultra-low-headroom battery-powered applications demanding high accuracy, low noise, and intelligent power monitoring - targeting portable instrumentation and communications equipment.

FAQ

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

The ZLDO285T8TA requires Vin ≥ Vout + dropout voltage. At 300 mA, dropout is 100 mV (max), so minimum Vin = 2.85 V + 0.1 V = 2.95 V. Operation below this will cause output sag; the LBF activates earlier (at ~3.05 V) to warn of impending dropout.

Can Pin 6 (D/C) be grounded to simplify layout?

No - Pin 6 is internally connected to a sensitive bias node and must remain unconnected. Grounding or routing it risks destabilizing the error amplifier, causing oscillation or erratic regulation. The datasheet explicitly states "Do Not Connect" and warns against any external connection.

How does the low-battery flag behave under temperature variation?

The LBF threshold shifts with temperature: at –40°C it triggers at ~3.04 V, at +85°C at ~3.10 V (for Vout = 2.85 V). This corresponds to a ΔV of ±30 mV over full range - sufficient for reliable system-level warning without false triggers in most battery chemistries.

Is an input capacitor required for stable operation?

An input capacitor is not mandatory per datasheet, but a 100 nF ceramic cap placed near Pin 3 (Vin) is strongly recommended to suppress high-frequency noise coupling and limit voltage spikes during load transients - especially when sourced from long traces or switching converters.