NCL30100 — 70V High-Side Buck Constant-Current LED Driver

Overview

The NCL30100 (NCL30100SNT1G) is a 70V step-down (buck) constant-current LED driver IC manufactured by ON Semiconductor. Enclosed in a compact TSOT-23 5-lead (SOT-23-5) package, it is designed to drive strings of high-brightness LEDs directly from unregulated 6.0V to 70.0V DC power supplies.

Operating on a peak current-mode control scheme with constant off-time, the NCL30100 requires minimal external components (an inductor, Schottky diode, sense resistor, and input capacitor) while delivering up to 95% efficiency. Its dedicated PWM input enables wide-range PWM dimming from low frequencies up to 5 kHz.

Quick reference


Input Supply Voltage (`VIN`)	6.0 V to 70.0 V DC
Maximum Switch Voltage	$70.0\text{ V}$ DC
Control Architecture	Peak Current-Mode / Constant Off-Time
Efficiency	Up to $95\%$ typical
Dimming	Dedicated PWM Dimming Pin (`PWM`, up to 5 kHz)
Package	TSOT-23 5-lead (SOT-23-5)

Pinout (TSOT-23-5 Package)

text

             ┌───┴───┐
        SW  1│ 1   5 │ VIN (+6V to +70V)
       GND  2│       │
       PWM  3│NCL30100│4 CS (Current Sense Input)
             └───────┘

Pin	Name	Type	Description
1	`SW`	Output	Internal MOSFET Switch Drain (Connect to Schottky Diode & Inductor)
2	`GND`	Power	Ground Reference (0 V)
3	`PWM`	Input	Logic PWM Dimming Input (High = Enable output switch; Low = Shutdown output)
4	`CS`	Input	High-Side Peak Current Sense Input
5	`VIN`	Power	Power Supply Input (+6.0V to +70.0V DC)

High Voltage Caution

Caution

High Input Voltage Hazard! The NCL30100 operates at input voltages up to $70.0\text{V}$ DC. Ensure that external Schottky diodes, inductors, and filter capacitors are rated for $\ge 100\text{V}$ breakdown.

Common mistakes

Leaving PWM (Pin 3) ungrounded or floating: PWM is a logic input. Connect PWM directly to VIN (via pull-up resistor) or a 3.3V/5V microcontroller pin for continuous non-dimmed lighting.

Notes

NCL30100 vs AL8807: NCL30100 supports high input voltages up to 70V DC (vs 30V on AL8807).