Texas Instruments TPS75100DSKT

Overview

TPS75100DSKT from Texas Instruments is a low-dropout linear LED current driver IC optimized for keypad and navigation pad backlighting in Li-ion–powered portable devices. It delivers matched constant current (±2% LED-to-LED) to four LEDs across two independent banks (D1A/D2A and D1B/D2B), supports PWM brightness control per bank, features 28-mV typical dropout at 5 mA, and operates from 2.7 V to 5.5 V input - enabling stable operation down to single-cell Li-ion battery cutoff.

For engineers reviewing the TPS75100DSKT datasheet, TPS75100DSKT pinout, TPS75100DSKT application, or TPS75100DSKT equivalent, this page provides verified functional context, validated WSON-10 package mapping, confirmed 10-pin pinout with terminal roles, real-world dimming timing constraints (≥33 µs PWM on-time), and direct alternatives for dual-bank LED current source replacement in space-constrained mobile designs.

Technical Context

The TPS75100DSKT implements four matched NMOS-based linear current sources arranged in two independently enabled banks (A and B), each driving two LEDs in common-cathode topology. Its architecture uses a single internal 1.225-V reference and 420:1 current mirror ratio to ensure tight output matching without external components when ISET is open.

Each bank accepts active-high PWM signals on ENA/ENB for brightness control, with shutdown supply current of 0.03 µA and thermal shutdown at 165°C. The device eliminates EMI by avoiding internal switching, relying solely on analog LDO-style regulation with load regulation of 0.8%/V and line regulation of 2.0%/V - critical for maintaining LED current stability during RF transmit transients.

Key Specifications

Pinout & Package

TPS75100DSKT is packaged in a 2.50-mm × 2.50-mm, 10-pin WSON (DSK) package with exposed thermal pad (Pin 5). This RoHS-compliant, lead-free package supports reflow soldering and provides 65.3°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS75100DSKT, TPS75103DSKT and TPS75105DSKT offer identical functionality and layout compatibility but differ in factory-set default current (3 mA and 5 mA respectively), enabling drop-in selection based on required baseline LED brightness without modifying circuit design or firmware PWM scaling.

Availability

TPS75100DSKT is available at Aetrix Electronics and suitable for keypad backlighting, navigation pad illumination, and white LED display backlighting requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for high-mix consumer electronics production.

Supply support for TPS75100DSKT 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 interface technologies.

The TPS7510x product line was designed specifically for low-power, space-constrained LED backlighting in portable consumer electronics - emphasizing ultra-low dropout, factory-trimmed current accuracy, and EMI-free linear operation.

FAQ

What is the default LED current setting for TPS75100DSKT when ISET is left open?

The TPS75100DSKT has no factory-programmed default current - it defaults to 0 mA per LED when ISET is open. Unlike TPS75103DSKT (3 mA) or TPS75105DSKT (5 mA), the TPS75100DSKT requires an external resistor on ISET to establish output current. This zero-default behavior allows maximum design flexibility for applications needing user-defined brightness levels via resistor selection.

Can TPS75100DSKT drive LEDs with forward voltages below 1.5 V?

No. The TPS75100DSKT requires a minimum output voltage of approximately 1.5 V on each DxA/DxB pin to maintain specified current accuracy. This limitation arises from its NMOS-based current source architecture. Red LEDs (typically 1.7 V) and white LEDs (2.8–3.6 V) are fully supported, but sub-1.5-V infrared or specialty diodes will exhibit degraded regulation and should not be used with TPS75100DSKT.

Is an external capacitor required on the VIN pin of TPS75100DSKT?

No external capacitor is required for stability on the VIN pin of TPS75100DSKT. The device is internally compensated and operates reliably with only standard PCB decoupling capacitance (e.g., 0.1 µF ceramic near the pin). Adding large bulk capacitors is unnecessary and may slow transient response; TI recommends using only minimal input bypassing per standard high-frequency noise suppression practice.

What happens if both ENA and ENB are tied together and driven by a single PWM signal?

When ENA and ENB are tied together and driven by one PWM signal, TPS75100DSKT operates both LED banks synchronously - turning all four LEDs on/off simultaneously. This configuration is electrically valid and maintains full current matching and regulation. However, it forfeits independent brightness control per bank, reducing flexibility for multi-zone lighting schemes such as keypad + display separation.

Does TPS75100DSKT support parallel connection of D1A and D2A outputs to drive a single high-current LED?

Yes - TPS75100DSKT allows paralleling D1A and D2A (or D1B and D2B) to double the output current capability, e.g., 50 mA total for one LED. This is explicitly permitted in the datasheet and maintains matching since both outputs share the same current reference. Ensure PCB traces and thermal layout support the increased current, and verify that combined voltage headroom remains above dropout requirements.