SSL5251T Mains dimmable buck-boost LED driver IC Rev. 1 20 July 2015 Preliminary data sheet 1. General description The SSL5251T is a highly integrated, high-precision dimmable controller with an external MOSFET. It is intended to drive LED lamps in dimmable lighting applications up to 25 W. The SSL5251T is designed for high power factor, phase-dimmable applications. The SSL5251T operates in Boundary Conduction Mode (BCM) with constant on-time control. It provides a constant output current control with good LED output current accuracy. Adaptive switching frequency gives freedom to choose the inductor, which enables the optimization of inductor size, efficiency and EMI. The SSL5251T can start up and operate in switching mode directly from an external resistor without capacitor charge pump supply or auxiliary supply. This feature simplifies the V supply. So, a low-cost off-the-shelf inductor can be used, which provides flexibility CC in application design. 2. Features and benefits Supports most available dimming solutions Deep dimming level Flicker-free dimming Low component count ensuring a compact solution and small, single layer Printed-Circuit Board (PCB) footprint Excellent line regulation and load regulation and good LED output current accuracy Efficient BCM operation with: Minimal reverse recovery losses in freewheel diode Zero Current Switching (ZCS) and Valley switching for turn-on of switch Minimum inductance value and size required High efficiency (up to 88 %) Ultra low IC current during operation (< 190 A) Auto-recovery protections: UnderVoltage LockOut (UVLO) Cycle-by-cycle OverCurrent Protection (OCP) Internal OverTemperature Protection (OTP) Output OverVoltage Protection (OVP) Output Short Protection (OSP) Extended IC lifetimeSSL5251T NXP Semiconductors Mains dimmable buck-boost LED driver IC 3. Applications The SSL5251T is intended for low-cost, non-isolated dimmable lighting applications that work from single mains voltage. 4. Quick reference data Table 1. Quick reference data Symbol Parameter Conditions Min Typ Max Unit 1 V supply voltage operating range 9.9 - 16 V CC R on-state source-switch DSon resistance T =25 C - 0.81 - j T = 125 C-1.2- j I input current on duty cycle < 20 % 2- +2 A I(SW) pin SW V input voltage on current limited at 8.8 mA 0.4 - +22 V I(SW) pin SW internal switch-off V input voltage on operating range in 0- 1.2 V I(ISNS) pin ISNS application V input/output operating range in 2- 4V IO(COMP) voltage on pin application COMP V input voltage on operating range in 0- 2V I(DIM) pin DIM application 1 An internal clamp sets the supply voltage. The current into the VCC pin must not exceed the maximum I VCC value (see Table 4). 5. Ordering information Table 2. Ordering information Type number Package Name Description Version SSL5251T SO8 plastic surface-mounted package 8 leads SOT96-1 SSL5251T All information provided in this document is subject to legal disclaimers. NXP Semiconductors N.V. 2015. All rights reserved. Preliminary data sheet Rev. 1 20 July 2015 2 of 18