TLV70433DBVR

The TLV70433DBVR is the 3.3-V fixed-output variant of TI’s TLV704 family of ultra-low-quiescent-current LDO regulators. The device is designed for battery-powered and low-power MCU applications where extended battery life is paramount. The 3.4-µA typical quiescent current (4.5 µA max) is stable across the entire 0-150 mA output load range, meaning the regulator draws virtually no extra current at light loads.

The wide 2.5-V to 24-V input range (30 V absolute max for new chip) allows direct connection to unregulated supplies such as 12-V or 24-V industrial buses, unconditioned solar panels, or multi-cell battery packs without pre-regulation. This eliminates the need for a front-end buck converter in many low-power applications, reducing BOM count and cost.

The 850-mV typical dropout voltage at 100 mA reflects the high input-to-output differential that the device can tolerate. While not a low-dropout device in the traditional sense (compared to sub-200-mV LDOs), the TLV704 trades dropout performance for ultra-low IQ, which is the correct trade-off for always-on battery-powered systems where load current is modest.

Internal soft-start limits inrush current into the output capacitor during power-up, preventing voltage overshoot on the output rail. The overcurrent protection uses a brick-wall current limit scheme that clamps output current during faults. Reverse polarity protection prevents damage when input voltage is applied in reverse, a common failure mode in battery-powered systems.

The SOT-23-5 package (2.9 x 1.6 mm) occupies only 4.64 mm² of board area, making the TLV70433DBVR one of the smallest 24-V LDOs available. The MSL-1 rating allows unlimited floor life before soldering, simplifying manufacturing logistics. The device requires only a 0.47-µF minimum output capacitor (1 µF recommended), enabling compact layouts.

**CMOS Pass Element:** The TLV704 uses a P-channel MOSFET pass element controlled by an error amplifier. The error amplifier compares a fraction of the output voltage (via an internal R1/R2 divider for fixed-output versions) with a 1.205-V bandgap reference. The PMOS gate is driven to maintain regulation. The high RDS(on) of the PMOS accounts for the relatively high dropout voltage but enables the ultra-low 3.4-µA ground current.

**Ultra-Low Quiescent Current:** The TLV704 achieves 3.4-µA IQ by using a micropower bandgap reference and a minimal bias current architecture. Unlike bipolar LDOs that require 0.5-5 mA of ground current, the CMOS design draws nearly constant IQ across the entire load range, because the error amplifier and reference consume the vast majority of the ground current.

**Internal Soft-Start:** During power-up, an internal current source charges the output capacitor gradually. This limits inrush current, reduces output voltage overshoot, and prevents stress on the input supply. The soft-start time is proportional to the output capacitor value.

**Overcurrent Protection:** A brick-wall current limit senses output current and clamps it to a fixed level (typically 300 mA). When the load exceeds this limit, the output voltage drops while the current remains clamped. The device enters thermal cycling if power dissipation causes overheating.