Diodes Incorporated PAM2805AF

Overview

PAM2805AF from Diodes Incorporated is a 3-mode step-up DC-DC white LED driver IC with integrated 2A/100mΩ NMOS switch, 1MHz fixed-frequency operation, 95mV feedback voltage, and selectable output current up to 750mA via external resistor. It delivers 100% brightness, 25% dimming, and 8.5Hz blinking modes without external MCU control, targeting portable flashlight applications powered by 1–2-cell alkaline or NiMH batteries.

For engineers reviewing the PAM2805AF datasheet, PAM2805AF pinout, PAM2805AF application, or PAM2805AF equivalent, key selection criteria include low 0.9V start-up voltage, over-voltage (4.5V) and over-temperature (150°C) protection, TSOT26 package thermal resistance (θJA = 250°C/W), and FB-based LED current setting accuracy dependent on external resistor tolerance.

Technical Context

The PAM2805AF implements a constant-frequency current-mode boost converter architecture with internal power switch and analog feedback loop referenced to 95mV at the FB pin. Its 3-mode cycling logic is implemented in hardwired state machine logic-no firmware or external timing components required.

Mode transitions are triggered solely by VIN power-on/off events with automatic reset to full-brightness mode after >5s power-off interval. Blinking frequency is set by external 1µF capacitor on BLK pin and is trimmed to 8.5Hz ±15% across temperature and supply.

Key Specifications

Pinout & Package

Package: TSOT26 (6-pin, 1.6mm × 2.9mm × 0.6mm, 0.5mm pitch, Pb-free, RoHS-compliant).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar WLED boost driver applications.

Compared with AL8805W-7 and MT9700, the PAM2805AF uniquely integrates 3-mode sequencing, 1MHz switching, and 2A switch in TSOT26-reducing total solution size and eliminating firmware dependency for basic flashlight functionality.

Availability

PAM2805AF is available at Aetrix Electronics and suitable for portable flashlight, emergency beacon, USB-powered LED lamp, and industrial inspection light applications requiring stable component supply and long-term manufacturability.

Supply support for PAM2805AF 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 manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The PAM2805AF belongs to Diodes' Power Management product line, designed specifically for compact, battery-efficient lighting solutions where integration, low-voltage operation, and autonomous mode control are primary system requirements.

FAQ

What is the minimum input voltage required for the PAM2805AF to start regulating LED current?

The PAM2805AF starts regulation at 0.9V typical when delivering 200mA LED current. This low start-up voltage enables reliable operation across the full discharge curve of a single alkaline or NiMH cell, making it ideal for cost-sensitive, battery-constrained flashlight designs where runtime extension is critical.

How is LED current accuracy affected by the external sense resistor?

LED current is calculated as I_LED = 95mV / R_S, so accuracy depends directly on resistor tolerance and temperature coefficient. A 1% tolerance, 100ppm/°C resistor yields ±1.5% current error over –40°C to +85°C. Lower-tolerance resistors improve accuracy but increase cost; design trade-offs must consider LED binning and thermal derating requirements.

Can the blinking mode be disabled or reconfigured without modifying hardware?

No-the 3-mode cycling (bright → dim → blink → bright) is hardwired and cannot be disabled or reordered via pins or registers. Leaving the BLK pin unconnected disables blinking, forcing only bright/dim cycling. Full mode disable requires external VIN control or PCB-level modification; no software or configuration interface exists.

What thermal considerations apply when operating the PAM2805AF at 750mA output current?

At 750mA with 3.4V LED forward voltage and 2.4V input, power dissipation reaches ~350mW. With θJA = 250°C/W, junction temperature rise is ~88°C above ambient. To stay within 125°C max T_J, ambient must remain below 37°C unless PCB copper area or airflow is enhanced-thermal relief pads and 2oz copper are strongly recommended.