NCP59150, NCV59150 Series
TYPICAL CHARACTERISTICS
Figure 21. Line Transient Response
Figure 22. Load Transient Response
APPLICATIONS INFORMATION
Output Capacitor and Stability
Enable Input
The NCP59150 series requires an output capacitor for
stable operation. The NCP59150 series is designed to
operate with ceramic output capacitors. The recommended
output capacitance value is 47
mF
or greater. Such capacitors
help to improve transient response and noise reduction at
high frequency.
Input Capacitor
Some NCP59150 series members also feature an enable
input for on/off control of the device. It’s shutdown state
draws “zero” current from input voltage supply (only
microamperes of leakage). The enable input is TTL/CMOS
compatible for simple logic interface, but can be connected
up to V
IN
.
Overcurrent and Reverse Output Current Protection
An input capacitor of 1.0
mF
or greater is recommended
when the device is more than 4 inches away from the bulk
supply capacitance, or when the supply is a battery. Small,
surface−mount chip capacitors can be used for the
bypassing. The capacitor should be place within 1 inch of
the device for optimal performance. Larger values will help
to improve ripple rejection by bypassing the input of the
regulator, further improving the integrity of the output
voltage.
Minimum Load Current
The NCP59150 regulator is specified between finite
loads. A 5 mA minimum load current is necessary for proper
operation.
Error Flag
Some NCP59150 series members feature an error flag
circuit that monitors the output voltage and signals an error
condition when the voltage is 5% below the nominal output
voltage. The error flag is an open−collector output that can
sink up to 5 mA typically during a V
OUT
fault condition.
The FLG output is overload protected when a short circuit
of the pullup load resistor occurs in the application. This is
guaranteed in the full range of FLG output voltage Max
ratings (see Max Ratings table). Please be aware operation in
this mode is not recommended, power dissipated in the device
can impact on output voltage precision and other device
characteristics.
The NCP59150 regulator is fully protected from damage
due to output current overload and output short conditions.
When NCP59150 output is overloaded, Output Current
limiting is provided. This limiting is linear; output current
during overload or output short conditions is constant. These
features are advantageous for powering FPGAs and other
ICs having current consumption higher than nominal during
their startup.
Thermal shutdown disables the NCP59150 device when
the die temperature exceeds the maximum safe operating
temperature.
When NCP59150 is disabled and (V
OUT
– V
IN
) voltage
difference is less than 6.5 V in the application, the output
structure of these regulators is able to withstand output
voltage (backup battery as example) to be applied without
reverse current flow. Of course the additional current
flowing through the feedback resistor divider inside the
Fixed Voltage devices (30
mA
typically at nominal output
voltage) needs to be included in the backup battery
discharging calculations.
Adjustable Voltage Design
The NCP/NCV59152 Adjustable voltage Device Output
voltage is set by the ratio of two external resistors as shown
in Figure 23.
The device maintains the voltage at the ADJ pin at 1.24 V
referenced to ground. The current in R2 is then equal to
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