Infineon Technologies TLF4949SJXUMA1

Overview

TLF4949SJXUMA1 from Infineon is a monolithic 5 V low-dropout linear voltage regulator with integrated reset circuit, voltage sense comparator, and preregulator output-designed for automotive microcontroller supply. It operates from 5.5 V to 28 V input, delivers up to 100 mA, maintains ±1% output accuracy at 5 V, and features <0.5 V dropout at 100 mA load in automotive environments.

For engineers reviewing the TLF4949SJXUMA1 datasheet, TLF4949SJXUMA1 pinout, TLF4949SJXUMA1 application, or TLF4949SJXUMA1 equivalent, key selection criteria include AEC-Q100 qualification, programmable reset delay via external capacitor, open-collector sense/reset outputs, thermal shutdown behavior, and PG-DSO-8 exposed pad thermal performance.

Technical Context

The TLF4949SJXUMA1 integrates a bandgap-referenced LDO regulator, undervoltage reset generator with adjustable delay (via capacitor on D pin), and independent voltage sense comparator (SI/SO). Its preregulator output (PRE) supplies auxiliary circuitry while enabling extended input operation down to 3.5 V in tracking mode.

It implements foldback current limiting (120–400 mA), thermal shutdown at 165 °C, short-circuit protection, and supports transient input up to 40 V for <1 s. The device uses an internal pass transistor with 0.1–0.5 V dropout across 10–100 mA load range and maintains 4.85–5.15 V output over full temperature and load conditions.

Key Specifications

Pinout & Package

TLF4949SJXUMA1 is housed in PG-DSO-8 package with exposed thermal pad (EP), optimized for automotive PCB layouts requiring high thermal reliability and compact footprint. The exposed pad must be soldered to PCB ground plane and thermal copper area for effective heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive LDO regulator applications.

Compared with TLF4949SJXUMA1, the EJ variant improves thermal performance by 55% but requires larger PCB thermal pad; the TLF49492SJ offers tighter regulation and lower IQ at cost of minor footprint compatibility-both retain identical pinout and functional interface.

Availability

TLF4949SJXUMA1 is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera ECUs, and telematics gateways requiring stable component supply under AEC-Q100-compliant automotive conditions.

Supply support for TLF4949SJXUMA1 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 German semiconductor manufacturer specializing in power management, automotive ICs, and security solutions, with global manufacturing and automotive qualification infrastructure.

The OPTIREG™ linear product line delivers AEC-Q100-qualified voltage regulators for automotive subsystems-designed specifically for robustness against load dump, cold crank, and long-term reliability in harsh environments.

FAQ

What is the maximum transient input voltage the TLF4949SJXUMA1 can withstand?

The TLF4949SJXUMA1 supports transient input voltages up to 40 V for durations less than 1 second, as specified in its absolute maximum ratings. This capability enables reliable operation during automotive load-dump events. Sustained operation above 28 V is not permitted, and thermal limits must be observed during transients-especially at high output current-to avoid exceeding 165 °C junction temperature.

How is the reset delay time configured on the TLF4949SJXUMA1?

The reset delay is set by connecting an external capacitor between pin D (pin 4) and GND. The delay time scales approximately linearly with capacitance-e.g., 100 nF yields ~100 ms, 1 µF yields ~1 s-per the datasheet's characteristic curve. No resistor is required; the internal current source charges the capacitor to generate the timed reset release. The delay begins after VOUT reaches regulation and ends when the internal threshold is crossed.

Does the TLF4949SJXUMA1 require an external pull-up resistor on the RO pin?

Yes, the RO (reset output) pin is an open-collector output and requires an external pull-up resistor to a valid logic-high voltage (e.g., 5 V or 3.3 V) to generate a functional active-low reset signal. Typical values range from 4.7 kΩ to 10 kΩ. Without pull-up, RO remains floating and cannot assert reset to downstream logic. The same applies to the SO (sense output) pin when used.

Can the SI (sense input) pin monitor voltages outside the 5 V output rail?

Yes, the SI pin accepts input voltages from –30 V to +40 V relative to GND, enabling direct monitoring of battery, alternator, or other system rails independent of the 5 V output. The internal comparator triggers SO when SI falls below VOUT × 0.9 (typical), allowing flexible undervoltage detection thresholds. No level-shifting circuitry is needed, simplifying multi-rail supervision.