UMW PT4115 Overview
The UMW PT4115 is a step-down (buck) constant current LED driver IC operating in continuous inductor current conduction mode (CCM), purpose-designed to provide precise, efficient LED current regulation for single or multi-LED series strings from a wide DC input supply. With an input voltage range of 6V to 30V, a maximum output current of 1.2A, and a switching frequency of 1MHz, the UMW PT4115 covers the power requirements of LED arrays from low-power indicator strings to multi-watt high-brightness lighting modules — depending on the input voltage and external inductor selection. Output current accuracy is guaranteed at ±5%, ensuring consistent LED brightness across production batches without individual trimming.
A key integration feature of the UMW PT4115 is its built-in power switch combined with high-side current sampling, which sets the average LED current via a single external sense resistor — eliminating the need for an external switching MOSFET and simplifying the overall circuit to very few external components: typically just an inductor, a diode, a sense resistor, and filter capacitors. The DIM pin is a versatile multipurpose input that supports three control modes from a single connection: LED on/off switching (digital control), analogue dimming (by varying the DIM voltage between 0.3V and VIN), and PWM dimming (by applying a PWM signal, with duty cycle linearly controlling LED current). When the DIM voltage falls below 0.3V, the internal switch is turned off and the PT4115 enters a standby state with extremely low quiescent current — making it suitable for battery-powered and energy-managed lighting systems where idle power draw matters.
The UMW PT4115 achieves up to 97% conversion efficiency thanks to its CCM operation, integrated low RDS(on) power switch, and 1MHz switching frequency that minimises inductor copper losses. This efficiency level is particularly valuable in high-power LED applications where thermal management is critical. UMW manufactures the PT4115 in the SOT-89-5 package — a compact, thermally capable 5-pin SMD format with an exposed tab that facilitates heat dissipation to the PCB copper. ABL Semi stocks the UMW PT4115 as a fully authentic, original factory product with flexible MOQ and compliance documentation for UK and European customers, and as a direct pin-to-pin replacement for the original PT4115 and comparable LED driver ICs.
Key Specifications
| Parameter | Value |
|---|---|
| Device Type | Step-Down (Buck) Constant Current LED Driver |
| Input Voltage Range (VInput) | 6V to 30V DC |
| Maximum Output Current (IOutput) | 1.2A |
| Output Current Accuracy | ±5% |
| Switching Frequency | 1MHz |
| Conversion Efficiency | Up to 97% |
| Conduction Mode | Continuous Inductor Current (CCM) |
| Integrated Power Switch | Yes (built-in, high-side current sampling) |
| DIM Pin Functions | On/off switch, analogue dimming, PWM dimming (multiplexed) |
| Standby Threshold (DIM pin) | <0.3V → ultra-low quiescent current standby |
| Current Setting Method | Single external sense resistor |
| Package | SOT-89-5 |
Applications
The UMW PT4115 is suited to any DC-input LED lighting application requiring accurate constant current regulation, high efficiency, and flexible dimming control from a compact, low-component-count driver IC. Primary application areas include LED downlight and spotlight drivers, solar-powered LED garden and pathway lighting, automotive LED interior and exterior strip lighting, LED signage and display panel drivers, and industrial work light modules. The device is equally applicable in e-bike and electric vehicle LED lighting systems, portable battery-powered LED torches and lanterns, and smart home LED retrofit bulb drivers, where its 6V–30V input range, 97% efficiency, and single-pin PWM dimming provide a versatile and energy-efficient constant current LED drive solution.
Pin-to-Pin Compatible Alternatives
The UMW PT4115 shares the SOT-89-5 package and constant current buck LED driver pinout with the original PT4115 and several widely used LED driver ICs, enabling direct board-level substitution to reduce procurement cost and establish secondary supply sources without any circuit or layout changes.
| Reference Part Number | Original Manufacturer | Why Choose UMW PT4115 |
|---|---|---|
| PT4115 | PowTech (original designer) | The original reference device; UMW PT4115 is a fully pin-compatible replacement in SOT-89-5 with identical 30V/1.2A/1MHz specification and ±5% current accuracy at a lower unit cost from ABL Semi stock |
| AL8805W5-7 | Diodes Inc. | Step-down LED driver in SOT-89-5 with comparable 1MHz switching and buck constant current architecture; UMW PT4115 provides equivalent performance with up to 97% efficiency and the same DIM pin versatility |
| LM3409MYX/NOPB | Texas Instruments | Hysteretic buck LED controller in SOT-23; UMW PT4115 provides a simpler fully integrated solution in SOT-89-5 with a built-in switch, higher 97% efficiency, and a single external sense resistor for current setting |
| NCV3065DR2G | onsemi | Step-down LED driver in SOP-8; UMW PT4115 offers an equivalent constant current buck solution in the smaller SOT-89-5 footprint with 1MHz switching enabling smaller external passives |
| CAT4201TD-GT3 | onsemi | Constant current LED driver in SOT-89; UMW PT4115 provides comparable drive capability with higher efficiency (97%), wider 6V–30V input range, and PWM/analogue/digital triple dimming from a single DIM pin |
Frequently Asked Questions
Is UMW PT4115 RoHS compliant?
Yes. The UMW PT4115 is fully RoHS compliant. UMW manufactures the PT4115 in accordance with EU RoHS Directive 2011/65/EU, ensuring the device is free from restricted hazardous substances including lead and mercury. ABL Semi can provide full compliance and trade documentation upon request to support UK and European regulatory and procurement requirements.
What are the pin-to-pin replacements for UMW PT4115?
The UMW PT4115 is a direct pin-to-pin replacement for the original PowTech PT4115 and is footprint-compatible with the Diodes Inc. AL8805W5-7 and onsemi CAT4201TD in the SOT-89-5 package, all sharing a comparable step-down constant current LED driver architecture. Refer to the compatibility table above for a detailed comparison.
What is the minimum order quantity (MOQ) for UMW PT4115?
ABL Semi offers flexible MOQ for UMW PT4115, supporting both prototype quantities and mass production orders. Contact us for current stock and pricing.
What package options are available for UMW PT4115?
The UMW PT4115 is available in the SOT-89-5 (5-pin small outline transistor) surface-mount package. The SOT-89-5 provides an exposed tab on the underside that, when soldered to PCB copper, improves thermal dissipation — an important consideration at 1.2A output current in continuous operation. The pinout is shared with the original PowTech PT4115 and equivalent LED driver ICs from Diodes Inc. and onsemi in the same package. Contact ABL Semi to confirm current stock availability.
How do I calculate the output current setting resistor for the UMW PT4115?
The UMW PT4115 sets average LED current using a single external sense resistor (RSET) connected between the CS pin and ground. The LED current is determined by the formula: ILED = 0.1V / RSET, where 0.1V is the typical internal reference threshold voltage at the CS pin. For example, to set a 350mA LED current: RSET = 0.1V / 0.35A ≈ 0.286Ω (use 0.27Ω or 0.3Ω standard value). For the maximum 1.2A output: RSET = 0.1V / 1.2A ≈ 0.083Ω (use 82mΩ or 100mΩ). The sense resistor must be rated for the power dissipation: P = I² × R — at 1.2A and 83mΩ, this is approximately 120mW, so a 0402 or 0603 resistor rated at 250mW or above is appropriate. A 1% tolerance resistor is recommended to achieve the specified ±5% LED current accuracy.
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