Diodes Incorporated PAM2861CBR

Overview

PAM2861CBR from Diodes Incorporated is a continuous-mode inductive step-down LED driver IC with integrated 40V NDMOS switch, designed to drive single or multiple series-connected LEDs from 6V–40V input. It delivers up to 1A output current (±5% accuracy), supports DC/PWM dimming via VSET pin, and includes open/short LED protection. Used in industrial lighting and illuminated signage where high efficiency (up to 97%) and wide input range are critical.

For engineers reviewing the PAM2861CBR datasheet, PAM2861CBR pinout, PAM2861CBR application, or PAM2861CBR equivalent, key selection criteria include its internal switch rating (40V, 0.3Ω R_DS(on)), adjustable current sensing (0.1V threshold), soft-start control via external capacitor on VSET, and dual-package availability (SOT89-5 for higher thermal performance).

Technical Context

The PAM2861CBR implements a constant-current buck regulator architecture with high-side current sensing using an external resistor between VIN and ISENSE. Its internal comparator monitors voltage drop across RS to regulate average LED current with 100mV nominal sense threshold and ±13% hysteresis.

Control is implemented through the multifunction VSET pin: logic-level shutdown (<0.2V), linear dimming (0.3–2.5V), or PWM dimming (<500Hz); soft-start time scales linearly with external capacitance (1.5ms/nF). Switching frequency operates from 233kHz (typ.) up to 1MHz, with duty cycle constrained between 25% and 75% for stability.

Key Specifications

Pinout & Package

SOT89-5 package: thermally enhanced 5-pin surface-mount outline with exposed pad for improved heat dissipation; JEDEC-compliant footprint (D=4.50mm, E=2.50mm, H=4.10mm); MSL3 moisture sensitivity level.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8862SP-13 and MPQ4425AGU-AEC1-P, the PAM2861CBR offers optimal integration (single-chip solution), widest input range among SOT89-5 LED drivers, and lowest BOM cost for industrial 6–40V applications-without sacrificing protection or dimming flexibility.

Availability

PAM2861CBR is available at Aetrix Electronics and suitable for industrial lighting systems, illuminated signage, low-voltage halogen replacement, and transportation interior lighting requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PAM2861CBR 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, specializing in power management, signal integrity, and connectivity solutions for industrial, computing, and consumer markets.

The PAM2861 belongs to Diodes' LED Driver product line, engineered for high-efficiency, thermally robust constant-current regulation in non-isolated buck topologies-targeting cost-sensitive, space-constrained lighting applications.

FAQ

What is the maximum allowable sense resistor value for 1A output?

The PAM2861CBR sets nominal output current as I_OUT = 0.1 / R_S. For 1A, R_S must be 0.1Ω. The datasheet specifies this as the minimum allowed value under floating-VSET conditions to keep peak switch current below 1.5A. Larger values reduce output current proportionally (e.g., 0.3Ω yields ~333mA), but do not extend beyond the 12–100% dimming range unless VSET is actively driven.

Can the PAM2861CBR drive more than one LED string in parallel?

No-PAM2861CBR is designed for single-string constant-current operation. Driving multiple parallel strings without individual current regulation causes mismatch due to V_F variations, leading to uneven brightness and potential thermal runaway. For multi-string applications, use separate PAM2861CBR channels or a matrix driver IC with per-string sensing.

What is the recommended input capacitor type and placement for PAM2861CBR?

A minimum 10µF X7R ceramic capacitor is required, placed directly between VIN and GND with shortest possible trace length. X7R dielectric ensures stable capacitance across temperature and voltage. Avoid Y5V types due to severe capacitance loss at bias. For high-ripple or low-input-voltage operation, increase to 22µF or add bulk electrolytic in parallel.

Does the SOT89-5 package (CBR suffix) support thermal pad soldering to PCB copper?

Yes-the SOT89-5 package includes an exposed thermal pad (pin 2 is GND-connected) that must be soldered to a minimum 100mm² copper pour with ≥4 thermal vias (0.3mm diameter) to inner ground planes. This achieves the rated θ_JA = 160°C/W and enables full 1A operation at +85°C ambient without derating.