TPS715A-NM Datasheet, PDF (9/20 Pages) Texas Instruments – 24-V High Input Voltage, Micropower, 80-mA LDO Voltage Regulator

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TPS715A-NM
SBVS340 – JUNE 2017
6.3 Feature Description
6.3.1 Wide Supply Range
This device has an operational input supply range of 2.5 V to 24 V, allowing for a wide range of applications. This
wide supply range is ideal for applications that have either large transients or high dc voltage supplies.
6.3.2 Low Supply Current
This device only requires 3.2 µA (typical) of supply current and has a maximum current consumption of 5.8 µA at
–40°C to 125°C.
6.3.3 Stable With Any Capacitor ≥ 0.47 µF
Any capacitor, including both ceramic and tantalum, greater than or equal to 0.47 μF properly stabilizes this loop.
6.3.4 Internal Current Limit
The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. The
LDO is not designed to operate in a steady-state current limit. During a current limit event, the LDO sources
constant current. Therefore, the output voltage falls when load impedance decreases.
NOTE
If a current limit occurs and the resulting output voltage is low, excessive power is
dissipated across the LDO, resulting in possible damage to the device.
6.3.5 Reverse Current
The TPS715A-NM device PMOS-pass transistor has a built-in back diode that conducts current when the input
voltage drops below the output voltage (for example, during power down). Current is conducted from the output
to the input and is not internally limited. If extended reverse voltage operation is anticipated, external limiting may
be required.
6.4 Device Functional Modes
Table 1 provides a quick comparison between the normal, dropout, and disabled modes of operation.
Table 1. Device Functional Mode Comparison
OPERATING MODE
Normal
Dropout
Disabled
PARAMETER
V_IN
V_IN > V_OUT(nom) + V_DO
V_IN < V_OUT(nom) + V_DO
—
I_OUT
I_OUT < I_CL
I_OUT < I_CL
—
6.4.1 Normal Operation
The device regulates to the nominal output voltage under the following conditions:
• The input voltage is greater than the nominal output voltage plus the dropout voltage (V_OUT(nom) + V_DO).
• The output current is less than the current limit (I_OUT < I_CL).
• The device junction temperature is less than 125°C.
6.4.2 Dropout Operation
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, the output voltage
tracks the input voltage. During this mode, the transient performance of the device becomes 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.
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