Texas Instruments TPS75103YFFT

Overview

TPS75103YFFT from Texas Instruments is a low-dropout linear LED current driver with two independent 2-LED banks (D1A/D2A and D1B/D2B), delivering up to 25 mA per channel in common-cathode topology. It features 2% LED-to-LED current matching, 28-mV typical dropout at 5 mA, factory-programmable default current (±0.5% typical accuracy), and PWM brightness control via ENA/ENB pins - optimized for Li-ion–powered keypad and display backlighting in mobile handsets.

For engineers reviewing the TPS75103YFFT datasheet, TPS75103YFFT pinout, TPS75103YFFT application, or TPS75103YFFT equivalent, key selection criteria include per-bank PWM dimming capability, ultra-low dropout for battery headroom preservation, factory-set current options (3–10 mA), thermal shutdown (165°C), and compatibility with 0.4-mm-pitch DSBGA (YFF) packaging for space-constrained portable designs.

Technical Context

The TPS75103YFFT implements four matched NMOS-based linear current sources, each regulated by a precision 1.225-V internal reference and mirrored with 420:1 ratio. Current matching is performed across all four channels concurrently, not per bank, enabling consistent illumination despite LED V_F variation. Dropout voltage remains stable down to 28 mV at 5 mA, supporting operation as low as 2.7 V input - critical for single-cell Li-ion discharge profiles.

Each bank (A/B) accepts independent active-high PWM signals on ENA/ENB pins, with minimum 33-µs on-time required for full-current settling. The ISET pin auto-detects external resistor presence (>3 µA current) and defaults to factory EEPROM-programmed current when open - eliminating BOM components while maintaining ±0.5% typical accuracy without trimming.

Key Specifications

Pinout & Package

TPS75103YFFT uses a 9-ball, 0.4-mm pitch wafer chip-scale package (DSBGA/YFF), measuring 1.208 mm × 1.208 mm. This ultra-compact footprint is optimized for front-side placement beneath narrow bezels in smartphones and PDAs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED current source applications.

Compared with TPS75103YFFT, TPS75105YFFT offers plug-and-play 5-mA operation without resistor selection overhead, while TPS75100YFFT provides lowest quiescent current among the YFF variants - enabling trade-offs between brightness, power, and BOM simplicity within the same footprint and layout.

Availability

TPS75103YFFT is available at Aetrix Electronics and suitable for keypad backlighting, display edge lighting, and navigation pad illumination requiring stable component supply across consumer electronics production cycles.

Supply support for TPS75103YFFT 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and digital signal technologies, with decades of expertise in power management and precision analog ICs.

The TPS7510x family was designed specifically for low-power, space-constrained LED backlighting in mobile handsets - prioritizing ultra-low dropout, factory-programmable current, and EMI-free linear operation over switching efficiency.

FAQ

What is the factory-programmed default current for TPS75103YFFT?

The TPS75103YFFT is factory-programmed to deliver 3 mA per LED channel when the ISET pin is left unconnected. This value is trimmed to ±0.5% typical accuracy using on-die EEPROM, eliminating the need for external current-setting resistors in basic implementations. The device supports seven other factory presets (4–10 mA) across the TPS7510x family, but TPS75103YFFT specifically ships with the 3-mA configuration.

Can TPS75103YFFT drive LEDs with forward voltages above 3.3 V?

Yes, TPS75103YFFT supports LED forward voltages up to VIN – V_DO, where V_DO is as low as 28 mV at 5 mA. With a 3.8-V supply, it can regulate LEDs with V_F up to ~3.77 V. However, minimum recommended V_F is 1.5 V for optimal accuracy due to NMOS output stage headroom requirements - making it suitable for white (3.0–3.6 V) and red (1.7–2.2 V) LEDs, but not sub-1.5-V IR types.

How does PWM dimming work on TPS75103YFFT, and what is the minimum pulse width?

TPS75103YFFT uses active-high PWM signals applied directly to ENA and ENB pins to modulate LED current. The duty cycle determines average brightness, with full current sourced during high periods. The minimum recommended on-time is 33 µs to ensure output current settles to target level; shorter pulses cause undershoot and nonlinear dimming. If one bank is already enabled, the second bank's minimum on-time reduces to ~22 µs due to shared internal biasing.

Is an external resistor required for TPS75103YFFT operation?

No, an external resistor is optional. TPS75103YFFT defaults to its factory-programmed 3-mA current when ISET is left open. An external resistor between ISET and GND is only needed to achieve non-standard currents (e.g., 7.5 mA) or tighter absolute accuracy than the ±0.5% typical factory trim. The device auto-detects resistor presence by monitoring ISET current (>3 µA triggers external mode).

What thermal considerations apply to TPS75103YFFT in a DSBGA package?

TPS75103YFFT in the YFF (DSBGA) package has a junction-to-ambient thermal resistance (R_θJA) of 101.6°C/W. At maximum 25 mA per channel (100 mA total) and 3.8-V input, power dissipation reaches ~100 mW - raising die temperature by ~10°C above ambient with minimal copper. For continuous full-load operation, use ≥2 cm² of inner-layer ground copper connected to the exposed die pad via multiple vias to maintain T_J ≤85°C.