Infineon Technologies IRS2505LTRPBF

Overview

IRS2505LTRPBF from Infineon is a critical-conduction mode (CrCM) PFC and SMPS control IC in 5-pin SOT-23 package, delivering regulated DC output voltage, cycle-by-cycle over-current protection, and output over-voltage protection without requiring a secondary winding. It achieves high power factor (>0.98) and ultra-low THD (<5%) in off-line LED drivers and electronic ballasts.

For engineers reviewing the IRS2505LTRPBF datasheet, IRS2505LTRPBF pinout, IRS2505LTRPBF application, or IRS2505LTRPBF equivalent, key selection criteria include VBUS regulation voltage (4.1 V), VCC clamp (20.8 V), minimum on-time (0.9 µs), OVP threshold (4.5 V), and CrCM operation with zero-crossing detection.

Technical Context

The IRS2505LTRPBF integrates a transconductance OTA-based error amplifier, smart zero-crossing detection circuitry referenced to VBUS, and a latch-free gate driver optimized for CrCM boost PFC stages. Its internal watchdog timer (140 µs nominal pulse interval) and blanking timers (tZXBLNK = 0.5 µs, tOC = 300 ns) ensure robust fault recovery and noise immunity during line transitions.

It operates with no auxiliary winding: VBUS sensing directly regulates output voltage via a resistor divider, while VPFC pin detects valley switching points using dual-threshold (0.40 V rising/falling) zero-crossing detection. The CMP pin delivers rail-to-rail OTA output (10.2 V high / 0 V low) driving external MOSFET gates through integrated 50 mA source / 450 mA sink capability.

Key Specifications

Pinout & Package

5-pin SOT-23 package with exposed thermal pad (JEDEC MO-178AA); compact footprint suitable for space-constrained LED drivers and ballasts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CrCM PFC control applications.

Compared with FAN7930C and UCC28051, the IRS2505LTRPBF uniquely combines CrCM operation, integrated gate driver, VBUS-sensed OVP, and ultra-low start-up current in a 5-pin SOT-23 - making it optimal for cost-sensitive, space-constrained, single-stage LED and ballast designs.

Availability

IRS2505LTRPBF is available at Aetrix Electronics and suitable for LED power supplies, electronic ballasts, off-line AC-DC adapters, and industrial control power supplies requiring stable component supply and long-term manufacturability.

Supply support for IRS2505LTRPBF 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

Infineon Technologies is a global semiconductor leader specializing in power management, automotive, and industrial control ICs, with core expertise in high-voltage analog and mixed-signal design.

The IRS2505L family targets cost-optimized, single-stage PFC solutions for lighting and industrial power conversion - emphasizing integration, reliability, and qualification to industrial standards (JEDEC JESD47E, MSL1).

FAQ

What is the function of the VBUS pin on the IRS2505LTRPBF?

The VBUS pin serves as the primary feedback and protection node: it senses the DC bus voltage via an external resistor divider to regulate output (4.1 V nominal), and simultaneously triggers over-voltage (4.5 V) and over-current (0.53 V) protection events. Its dual role eliminates need for separate sense and protection circuits.

Does the IRS2505LTRPBF require an auxiliary winding for start-up or bias?

No - the IRS2505LTRPBF uses ultra-low start-up current (46 µA max) to charge VCC directly from the rectified AC line via a high-value resistor, and derives regulation and protection from the main DC bus (VBUS). No auxiliary winding is needed for start-up, bias, or feedback.

How does the IRS2505LTRPBF achieve zero-crossing detection without a current-sense transformer?

It uses valley-switching detection on the PFC pin, sampling the boost diode cathode voltage through a resistive divider. Internal dual-threshold comparators (0.40 V rising/falling) detect the inductor current zero-crossing point, enabling CrCM timing without auxiliary windings or current-sense resistors.

What protection features are integrated into the IRS2505LTRPBF?

The IRS2505LTRPBF integrates cycle-by-cycle over-current protection (with 300 ns blanking), output over-voltage protection (4.5 V threshold on VBUS), VCC under-voltage lockout (7.9 V falling threshold), internal 20.8 V VCC clamp, and a watchdog timer that disables gate drive if zero-crossing pulses stop - covering startup, steady-state, and fault conditions.