SBVS054J November 2004 – April 2015 TPS730
The TPS730 family of low-dropout (LDO) regulators has been optimized for use in noise-sensitive, battery-operated equipment. The device features extremely low dropout voltages, high PSRR, ultra-low output noise, low quiescent current (170 μA typically), and enable-input to reduce supply currents to less than 1 μA when the regulator is turned off.
The TPS730 uses an undervoltage lockout (UVLO) circuit that disables the output until the input voltage is greater than the rising UVLO voltage. This circuit ensures that the device does not exhibit any unpredictable behavior when the supply voltage is lower than the operational range of the internal circuitry, VIN(min).
The enable pin (EN) is active high. Enable the device by forcing the EN pin to exceed VEN(high) (1.7 V, minimum). Turn off the device by forcing the EN pin to drop below 0.7 V. If shutdown capability is not required, connect EN to IN.
The TPS730 features internal current limiting and thermal protection. During normal operation, the TPS730 limits output current to approximately 400 mA. When current limiting engages, the output voltage scales back linearly until the overcurrent condition ends. While current limiting is designed to prevent gross device failure, do not exceed the power dissipation ratings of the package or the absolute maximum voltage ratings of the device.
The device regulates to the nominal output voltage under the following conditions:
If the input voltage is lower than the nominal output voltage plus the specified dropout voltage, but all other conditions are met for normal operation, the device operates in dropout mode. In this mode of operation, the output voltage is the same as the input voltage minus the dropout voltage. The transient performance of the device is significantly degraded because the pass device is in the linear region and no longer controls the current through the LDO. Line or load transients in dropout can result in large output voltage deviations.
The device is disabled under the following conditions:
Table 1 shows the conditions that lead to the different modes of operation.
|Normal mode||VIN > VOUT(nom) + VDO and
VIN > VIN(min)
|VEN > VEN(high)||IOUT < ILIM||TJ < 125°C|
|Dropout mode||VIN(min) < VIN < VOUT(nom) + VDO||VEN > VEN(high)||—||TJ < 125°C|
(any true condition disables the device)
|VIN < UVLOfalling||VEN < VEN(low)||—||TJ > 165°C(1)|