Texas Instruments TPS75105YFFT

Overview

TPS75105YFFT from Texas Instruments is a low-dropout linear LED current driver with two independent 2-LED banks in common-cathode topology, delivering up to 25 mA per channel with ±0.5% typical factory-set current accuracy, 28 mV typical dropout voltage at 5 mA, and PWM-controlled brightness via ENA/ENB pins. It targets Li-ion–powered keypad and navigation pad backlighting in compact mobile handsets.

For engineers reviewing the TPS75105YFFT datasheet, TPS75105YFFT pinout, TPS75105YFFT application, or TPS75105YFFT equivalent, key selection considerations include per-bank PWM dimming capability, factory-programmable default current (5 mA for TPS75105), ultra-low EMI due to no internal switching, WSON-10 package thermal performance (R_θJA = 65.3°C/W), and compatibility with single-cell battery input (2.7 V to 5.5 V).

Technical Context

The TPS75105YFFT implements four matched NMOS-based linear current sources-two per bank-with shared ISET reference and 420:1 current mirroring ratio. Its LDO architecture enables stable operation down to 28 mV headroom, supporting Li-ion battery discharge down to ~2.8 V while maintaining 5 mA output.

Each bank (A/B) features independent active-high enable inputs (ENA/ENB) that accept PWM signals with ≥33 µs minimum on-time; brightness scaling is achieved by duty-cycle modulation without altering current-setting components. Current matching across all four channels is maintained concurrently, not per-bank, with ≤2% variation at 25°C and ≤6% over –40°C to +85°C in the DSK (WSON) package.

Key Specifications

Pinout & Package

TPS75105YFFT uses the 2.50 mm × 2.50 mm, 10-pin WSON (DSK) package with exposed thermal pad (Pin 5). Pin 6 is NC (not connected); Pin 5 is GND pad and must be soldered for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS75105YFFT, TPS75103YFFT delivers lower baseline brightness with reduced power consumption, while TPS75100YFFT provides double the current for demanding optical output - all share identical control timing, thermal behavior, and PCB layout.

Availability

TPS75105YFFT is available at Aetrix Electronics and suitable for keypad backlighting, navigation pad illumination, and cellular handset LED applications requiring stable component supply, long-term manufacturability, and automotive-grade reliability screening.

Supply support for TPS75105YFFT 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 company specializing in analog and embedded processing solutions, with leadership in power management, signal chain, and high-reliability ICs.

The TPS7510x family is designed specifically for low-power, multi-LED backlighting in space-constrained portable electronics, emphasizing factory-trimmed accuracy, zero-EMI operation, and seamless integration with Li-ion battery systems.

FAQ

What is the factory-set LED current for TPS75105YFFT?

The TPS75105YFFT is factory-programmed to deliver 5 mA per LED channel with ±0.5% typical accuracy when the ISET pin is left unconnected. This eliminates the need for an external resistor and simplifies BOM management. The device automatically detects absence of external R_SET by monitoring ISET current (<3 µA) and defaults to this preset value. TPS75105YFFT maintains this accuracy across –40°C to +85°C operating temperature.

Can TPS75105YFFT drive LEDs with different forward voltages on the same bank?

Yes, TPS75105YFFT supports mixed-color LEDs (e.g., red and green) on the same bank due to its tight load regulation (0.8%/V) and minimum 1.5 V output requirement. Each current source operates independently, so variations in LED V_F - from 1.7 V (red) to 3.3 V (white) - do not affect current matching or stability, provided headroom (VIN – V_F) remains ≥100 mV. This capability is confirmed in the Electrical Characteristics table and Figure 12.

What is the minimum PWM on-time supported by TPS75105YFFT?

The TPS75105YFFT requires a minimum PWM on-time of 33 µs to achieve full rated current (5 mA) on any channel. Shorter pulses result in reduced average current due to finite turn-on slew rate. If one bank is already enabled, the second bank's minimum on-time decreases by ~10–12 µs (per Figure 4 and Figure 5), enabling faster interleaved dimming. This specification is explicitly stated in Section 6.3 (Recommended Operating Conditions) and validated in Figure 4.

Does TPS75105YFFT require output capacitors for stability?

No, TPS75105YFFT does not require external output capacitors. Its linear current-source architecture is inherently stable without compensation components. Section 8.1.3 explicitly states: "The TPS7510x does not require the use of any external capacitors for stable operation." Adding output caps may degrade transient response and is discouraged. Only standard 1-µF ceramic input decoupling at VIN is recommended per the Typical Application Diagram (Figure 13).

How does thermal performance differ between TPS75105YFFT and the DSBGA variant?

TPS75105YFFT uses the WSON-10 (DSK) package with R_θJA = 65.3°C/W, whereas the DSBGA (YFF) variant has R_θJA = 101.6°C/W. This 36% lower thermal resistance allows TPS75105YFFT to sustain 25 mA per channel at higher ambient temperatures or in tighter layouts. The WSON package also features an exposed thermal pad (Pin 5) that must be soldered to the PCB ground plane - a requirement not present in the 9-ball DSBGA. Both packages share identical electrical specs and pin functions.