CAT6242 Datasheet, PDF (9/14 Pages) ON Semiconductor – 1.3 Amp CMOS LDO Voltage Regulator

CAT6242
PIN FUNCTIONS
V_IN
Positive Power Input. Power is supplied to the device
through the V_IN pin. A bypass capacitor is required on this
pin if the device is more than six inches away from the main
input filter capacitor. In general it is advisable to include a
small bypass capacitor adjacent to the regulator. In
battery−powered circuits this is particularly important
because the output impedance of a battery rises with
frequency, so a bypass capacitor in the range of 1 mF to 10 mF
is recommended.
GND
Ground. The negative voltage of the input power source.
The center pad on the back of the package is also electrically
ground. This pad is used for cooling the device by making
connection to the buried ground plane through solder filled
vias or by contact with a topside copper surface exposed to
free flowing air.
ENABLE
ENABLE is an active high logic input which controls the
regulator’s the output state. If ENABLE < 0.4 V the
regulator is shutdown and V_OUT = 0 V. If ENABLE > 1.6 V
the regulator is active and supplying power to the load.
If the regulator is intended to operate continuously and
won’t be shut down from time to time ENABLE should be
tied to V_IN or left floating.
BYP
The Bypass Capacitor input is used to decrease output
voltage noise by placing a capacitor between BYP and
ground. The recommended range of capacitance is from
100 pF to 470 pF. Values larger than this will provide no
additional improvement and will further extend CAT6242’s
startup time.
A bypass capacitor is not required for operation and BYP
may be left open or floating if no capacitor is used but DO
NOT ground BYP as this will interfere with the error
amplifier’s functioning.
SENSE
SENSE is the sense input of the circuit and is connected
externally to the VOUT line.
V_OUT
V_OUT is the regulator’s output and supplies power to the
load. V_OUT can be shut off via the ENABLE input. All
CAT6242 family members are designed to block reverse
current, meaning anytime V_OUT becomes greater than V_IN
the pass FET will be shut off so there is no reverse current
flow from output to input. CAT6242 is also equipped with
an output discharge transistor that is turned ON anytime
ENABLE is at a logic Low. This transistor ensures V_OUT
discharges to 0 V when the regulator is shutdown. This is
especially important when powering digital circuitry
because if V_OUT fails to reach 0 V their POR (power−ON
reset) circuitry may not trigger and scrambled data or
unpredictable operations may result.
A minimum output capacitor of 2.2 mF should be placed
between V_OUT and GND to insure stable operation.
Increasing the size of C_OUT will improve transient response
to large changes in load current.
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