The TPS73xx devices are members of a family of micropower low-dropout (LDO) voltage regulators. They are differentiated from the TPS71xx and TPS72xx LDOs by their integrated delayed microprocessor-reset function. If the precision delayed reset is not required, the TPS71xx and TPS72xx should be considered.
The RESET\ output of the TPS73xx initiates a reset in microcomputer and microprocessor systems in the event of an undervoltage condition. An internal comparator in the TPS73xx monitors the output voltage of the regulator to detect an undervoltage condition on the regulated output voltage.
If that occurs, the RESET\ output (open-drain NMOS) turns on, taking the RESET\ signal low. RESET\ stays low for the duration of the undervoltage condition. Once the undervoltage condition ceases, a 200-ms (typ) time-out begins. At the completion of the 200-ms delay, RESET\ goes high.
An order of magnitude reduction in dropout voltage and quiescent current over conventional LDO performance is achieved by replacing the typical pnp pass transistor with a PMOS device.
Because the PMOS device behaves as a low-value resistor, the dropout voltage is very low (maximum of 35mV at an output current of 100 mA for the TPS7350) and is directly proportional to the output current (see Figure1). Additionally, since the PMOS pass element is a voltage-driven device, the quiescent current is low and remains constant, independent of output loading (typically 340 uA over the full range of output current, 0 mA to 500mA). These two key specifications yield a significant improvement in operating life for battery-powered systems.
The LDO family also features a sleep mode; applying a logic high signal to EN\ (enable\) shuts down the regulator, reducing the quiescent current to 0.5 uA maximum at TJ = 25°C.
The TPS73xx is offered in 2.5-V, 3-V, 3.3-V, 4.85-V, and 5-V fixed-voltage versions and in an adjustable version (programmable over the range of 1.2 V to 9.75 V). Output voltage tolerance is specified as a maximum of 2% over line, load, and temperature ranges (3% for the 2.5 V and the adjustable version). The TPS73xx family is available in PDIP (8 pin), SO (8 pin) and TSSOP (20 pin) packages. The TSSOP has a maximum height of 1.2mm.
