NXP Semiconductors SSL2109T/1,118

Overview

SSL2109T/1,118 from NXP Semiconductors is a high-voltage LED driver IC designed for non-dimmable, high-power-factor LED lighting applications operating directly from rectified mains (100 V, 120 V, or 230 V AC). It delivers ±5 % LED current accuracy, supports boundary conduction mode (BCM) operation up to 100 kHz, and enables buck, buck-boost, or flyback topologies using an external MOSFET. Its internal dV/dt supply and HV startup current source eliminate need for auxiliary windings in compact retrofit lamps.

For engineers reviewing the SSL2109T/1,118 datasheet, SSL2109T/1,118 pinout, SSL2109T/1,118 application, or SSL2109T/1,118 equivalent, key selection criteria include its driver-only architecture, valley-switching capability for ZVS turn-off, integrated brownout and short-winding protection, and compatibility with NTC-based thermal management in space-constrained LED lamp designs.

Technical Context

The SSL2109T/1,118 implements a peak-current-controlled Boundary Conduction Mode (BCM) controller with valley detection on the DRAIN pin to enable zero-voltage switching (ZVS) turn-off and minimize capacitive switching losses. Its internal dV/dt supply draws power capacitively from the drain node, eliminating auxiliary windings while maintaining stable VCC regulation across input voltage ranges.

It features cycle-by-cycle current control with leading-edge blanking (300 ns typ), overcurrent protection threshold of 500 mV on SOURCE, and latched short-winding protection triggered at 1.5 V on SOURCE. The DRIVER pin delivers 10.5 V max output with 0.28 A sink capability at 2 V, enabling robust gate drive for external high-voltage MOSFETs.

Key Specifications

Pinout & Package

SSL2109T/1,118 is housed in an SO8 package (SOT96-1), 3.9 mm body width, with standard 1.27 mm lead pitch and JEDEC MS-012 outline. Thermal resistance R_th(j-a) is 159 K/W in free air on a 2-layer 2 cm × 3 cm PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SSL21083T/1,118, the SSL2109T/1,118 trades integrated switch convenience for topology flexibility and lower standby loss; versus UCC28810DR, it delivers superior efficiency, reduced EMI, and enhanced protection integration - making it optimal for compact, high-reliability retrofit lamps.

Availability

SSL2109T/1,118 is available at Aetrix Electronics and suitable for LED retrofit lamps, compact AC-DC LED drivers, thermally sensitive LED fixtures, and mains-powered indicator lighting requiring stable component supply and long-term lifecycle continuity.

Supply support for SSL2109T/1,118 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The SSL2109T/1,118 belongs to NXP's SSL (Solid-State Lighting) controller family, engineered specifically for high-efficiency, non-dimmable LED drivers in space-constrained, cost-sensitive general lighting applications.

FAQ

What is the primary function of the SSL2109T/1,118 in an LED lighting system?

The SSL2109T/1,118 functions as a high-voltage, driver-only LED controller that manages an external MOSFET to regulate constant current through LED strings. It operates in boundary conduction mode with valley detection to achieve high efficiency (>95 %) and power factor >0.9 in buck, buck-boost, or flyback topologies. The SSL2109T/1,118 does not include an integrated power switch, distinguishing it from the SSL2108x series.

How does the SSL2109T/1,118 achieve startup without an auxiliary winding?

The SSL2109T/1,118 uses an internal high-voltage current source connected to the HV pin to provide initial power until the dV/dt supply on the DVDT pin becomes active. This allows direct startup from rectified mains voltage without requiring an auxiliary winding or external bias supply. Once running, the IC derives power capacitively from the drain node oscillation, sustaining VCC regulation. The SSL2109T/1,118 internal clamp limits VCC to 20 V maximum.

Can the SSL2109T/1,118 be used in dimmable applications?

No, the SSL2109T/1,118 is explicitly designed for non-dimmable LED lighting applications. It lacks dedicated dimming interfaces such as analog dimming pins or TRIAC-compatible leading-edge detection circuitry. While the NTC pin supports PWM-style on/off control via external digital signals, this is not compliant with industry-standard phase-cut or 0–10 V dimming protocols. For dimmable operation, NXP recommends the SSL2129AT or SSL21084AT instead of the SSL2109T/1,118.

What protection features are implemented in the SSL2109T/1,118?

The SSL2109T/1,118 integrates UnderVoltage LockOut (UVLO), Leading-Edge Blanking (LEB), OverCurrent Protection (OCP), Short-Winding Protection (SWP), Output Short Protection (OSP), Internal OverTemperature Protection (OTP), Brownout protection, and LED overtemperature control. SWP and OSP are latched protections requiring power cycle reset, while OTP and LED thermal protection use safe-restart behavior. All protections are validated per NXP's SSL2109T/1,118 datasheet Rev. 5.

What is the significance of the DRAIN pin in SSL2109T/1,118 operation?

The DRAIN pin on the SSL2109T/1,118 serves two critical roles: it provides valley detection for zero-voltage switching (ZVS) turn-on and acts as the high-side switch node for external MOSFET connection. During demagnetization, the IC monitors drain voltage oscillation amplitude (≥20 V) and frequency (200–1000 kHz) to identify the valley point and initiate the next switching cycle. This reduces switching losses and EMI. The SSL2109T/1,118 DRAIN pin is rated for −0.4 V to +600 V, supporting direct interface with 600 V MOSFETs.