Diodes Incorporated ZLDO485T8TC

Overview

ZLDO485T8TC from Diodes Incorporated (formerly Zetex) is an ultra-low-dropout linear regulator delivering a fixed 4.85 V output with 300 mA load capability, 30 mV dropout at 100 mA, 1 mA typical quiescent current, and integrated low-battery flag (LBF) and active-high shutdown control - used in battery-backed portable instrumentation where supply margin and graceful shutdown are critical.

For engineers reviewing the ZLDO485T8TC datasheet, ZLDO485T8TC pinout, ZLDO485T8TC application, or ZLDO485T8TC equivalent, key selection criteria include dropout voltage vs. load, LBF activation threshold (Vo + 0.2–0.4 V), shutdown leakage (<100 nA), thermal shutdown at 125°C, and SM8 package layout constraints for high-density PCBs.

Technical Context

The ZLDO485T8TC employs a precision bandgap reference to maintain ±2.5% output tolerance over –40°C to +85°C and achieves 100 ppm/°C typical output voltage temperature coefficient. Its error amplifier uses an external 10 pF capacitor (pin 8 to pin 5) for stability optimization.

It integrates dual protection functions: over-temperature shutdown at 125°C and low-battery detection triggered when Vin falls within 200–400 mV of Vout. The open-collector LBF output pulls low with ≤0.4 V saturation at 100 µA sink, while shutdown reduces quiescent current to 11 µA (typ).

Key Specifications

Pinout & Package

Package: SM8 (8-pin small-outline surface-mount, 4.9 mm × 6.0 mm, 1.27 mm pitch), thermally enhanced for 2 W dissipation on 2″×2″ PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-4802E/TT and TPS76348DBVR, the ZLDO485T8TC uniquely delivers 300 mA at ≤30 mV dropout *with* integrated LBF and thermal shutdown - making it irreplaceable in battery-critical portable systems where both runtime extension and fail-safe behavior are mandatory.

Availability

ZLDO485T8TC is available at Aetrix Electronics and suitable for battery-powered portable instrumentation, post-converter regulation in telecom power supplies, microcontroller-controlled power sequencing, and over-temperature monitoring systems requiring stable component supply and long-term lifecycle support.

Supply support for ZLDO485T8TC 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 solutions, with design and manufacturing operations across Asia, Europe, and the US.

The ZLDO series was developed by Zetex (acquired by Diodes Inc. in 2008) specifically for ultra-low-power, space-constrained battery-operated systems demanding sub-50 mV dropout, integrated fault signaling, and robust thermal behavior.

FAQ

What is the minimum input voltage required to maintain regulation at 300 mA load?

The ZLDO485T8TC maintains regulation as long as Vin ≥ Vout + dropout voltage. At 300 mA, maximum dropout is 200 mV (per datasheet absolute max), so minimum Vin = 4.85 V + 0.2 V = 5.05 V. For reliable operation, design with ≥5.1 V to accommodate tolerance and transient droop.

Can the LBF output drive a microcontroller interrupt pin directly?

Yes - the open-collector LBF output can sink ≥100 µA with ≤0.4 V saturation. Connect a 10 kΩ pull-up to 3.3 V or 5 V; the resulting logic-low signal meets standard CMOS input thresholds. No level-shifting is needed unless the MCU operates below 1.8 V.

Is the SM8 package RoHS-compliant and lead-free?

Yes - the ZLDO485T8TC in SM8 packaging (suffix T8) is RoHS-compliant and lead-free per Diodes Incorporated's product change notice PCN-2012-001, with matte-tin termination and halogen-free molding compound.

Why does the datasheet state "NOT RECOMMENDED FOR NEW DESIGNS"?

This advisory reflects Diodes Inc.'s end-of-life planning: newer alternatives like AP7361D-48YG-13 offer improved PSRR and lower IQ, but ZLDO485T8TC remains fully supported for legacy production and repair. Aetrix guarantees supply continuity through 2028 per manufacturer notification.