Texas Instruments TPS7A1108PDRVT

Overview

TPS7A1108PDRVT from Texas Instruments is a 500-mA ultra-low dropout linear regulator (LDO) with dual-rail operation (IN and BIAS), fixed 0.8-V output, 0.75-V minimum input voltage, 140-mV max dropout at 500 mA (DRV package), and 1.6-µA typical input quiescent current. It delivers 1.5% output accuracy over load, line, and temperature for powering low-voltage MCU cores and analog sensors in space-constrained portable electronics.

For engineers reviewing the TPS7A1108PDRVT datasheet, TPS7A1108PDRVT pinout, TPS7A1108PDRVT application, or TPS7A1108PDRVT equivalent, key selection criteria include its LILO (low-input/low-output) capability enabled by separate IN/BIAS rails, active output discharge, thermal shutdown, and compatibility with sub-1-V supply architectures requiring high PSRR (64 dB @ 1 kHz) and low noise (93.9 µVRMS).

Technical Context

The TPS7A1108PDRVT implements a dual-supply LDO architecture where the IN pin supplies power to the pass element while the BIAS pin powers internal control circuitry-enabling stable regulation even when VIN is as low as 0.75 V and VOUT is 0.8 V. Its global UVLO combines independent IN and BIAS undervoltage detection via AND logic to prevent startup until both rails exceed their thresholds (VIN > 675 mV, VBIAS > 1.54 V).

It features foldback current limiting (990 mA typical for DRV package), thermal shutdown at 160°C, and an active pulldown circuit (120-Ω resistor) for controlled output discharge during disable or fault. The device supports ceramic output capacitors from 2.2 µF to 22 µF with ESR < 250 mΩ and requires no external compensation.

Key Specifications

Pinout & Package

TPS7A1108PDRVT is housed in a 2.00-mm × 2.00-mm WSON-6 (DRV) package with exposed thermal pad. Pin 1 = OUT, Pin 2 = NC (no internal connection; recommended grounded for thermal relief), Pin 3 = EN, Pin 4 = BIAS, Pin 5 = GND, Pin 6 = IN.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A1108PDRVT, the 1.2-V and 0.5-V variants retain identical thermal, PSRR, and quiescent current behavior but shift the regulated output level-making them suitable for different core voltage requirements without altering board layout or support components.

Availability

TPS7A1108PDRVT is available at Aetrix Electronics and suitable for smart wearables, wireless earbuds, and portable medical devices requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for TPS7A1108PDRVT 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 power management technologies with decades of LDO design expertise.

The TPS7A11 family was engineered specifically for ultra-low-voltage, ultra-low-power portable systems-delivering LILO regulation, nanoscale quiescent current, and high PSRR in wafer-level chip-scale packages.

FAQ

What is the minimum input voltage required for TPS7A1108PDRVT to regulate 0.8 V?

The TPS7A1108PDRVT requires a minimum input voltage of 0.75 V. With its 140-mV maximum dropout at 500 mA (DRV package), it can sustain regulation down to VIN = VOUT + VDO = 0.94 V under full load. At light load, dropout drops further-enabling operation even closer to 0.8 V. This makes TPS7A1108PDRVT uniquely suited for deeply discharged batteries or stacked-cell architectures where headroom is extremely limited.

Does TPS7A1108PDRVT require an external pull-up resistor on the EN pin?

No, TPS7A1108PDRVT does not require an external pull-up on EN. The EN pin has negligible leakage (<10 nA), and the device supports direct connection to VIN or BIAS if enable control is unnecessary-provided VIN > 0.9 V. When interfacing with low-voltage GPIO (e.g., 0.8-V logic), a level-shifter or dedicated enable controller is needed since the EN threshold is fixed at 0.9 V minimum.

How does the BIAS pin improve efficiency in TPS7A1108PDRVT designs?

The BIAS pin in TPS7A1108PDRVT powers internal circuitry independently from the IN rail, allowing the main input (IN) to operate at ultra-low voltages (as low as 0.75 V) without compromising control loop stability or accuracy. For example, IN can be fed from a highly efficient buck converter's 0.85-V output, while BIAS is supplied from a 3.3-V battery or auxiliary rail-reducing total system power loss versus single-rail LDOs that force both functions through one low-voltage path.

Can TPS7A1108PDRVT be used without the BIAS supply?

No-TPS7A1108PDRVT requires a valid BIAS supply between 1.7 V and 5.5 V to operate. The BIAS pin is not optional; it powers the bandgap reference, error amplifier, and UVLO comparators. If only a single low-voltage rail is available, a charge pump or auxiliary LDO must generate the required BIAS voltage. Omitting BIAS causes the global UVLO to hold the device disabled regardless of IN or EN state.

What is the purpose of the NC pin on TPS7A1108PDRVT, and how should it be handled?

The NC (No Connect) pin on TPS7A1108PDRVT (Pin 2) is not internally bonded. TI recommends connecting it to GND to enhance thermal dissipation through the package body and improve solder joint reliability. Leaving it floating is electrically acceptable but forfeits thermal benefits. It must never be connected to any active signal or voltage rail, as it has no internal function and could risk unintended coupling.