CMPWR130SR Ver la hoja de datos (PDF) - California Micro Devices Corp
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CMPWR130SR Datasheet PDF : 6 Pages
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CALIFORNIA MICRO DEVICES
CMPWR130
Interface Signals
V is the power source for the internal regulator and is
CC
monitored continuously by an internal controller circuit.
Whenever VCC exceeds VCCSEL (4.30V TYP), the internal
regulator (300mA MAX) will be enabled and deliver a
fixed 3.3V at VOUT. When VCC falls below VCCDES (4.10V
TYP) the regulator will be disabled.
Internal loading on this pin is typically 0.6mA when the
regulator is enabled, which reduces to 0.2mA whenever
the regulator is disabled. If VCC falls below the voltage on
the VOUT pin the VCC loading will further reduce to only a
few microamperes.
During a VCC power up sequence, there will be an
effective step increase in V line current when the
CC
regulator is enabled. The amplitude of this step increase
will depend on the DC load current and any necessary
current required for charging/discharging the load
capacitance. This line current transient will cause a
voltage disturbance at the VCC pin. The magnitude of the
disturbance will be directly proportional to the effective
power supply source impedance being delivered to the
VCC input.
To prevent chatter during Select and Deselect transi-
tions, a built-in hysteresis voltage of 200mV has been
incorporated. It is recommended that the power supply
connected to the VCC input should have a source resis-
tance of less than 0.25Ω to minimize the event of chatter
during the enabling/disabling of the regulator.
An input filter capacitor in close proximity to the V pin
CC
will reduce the effective source impedance and help
minimize any disturbances. If the VCC pin is within a few
inches of the main input filter, a capacitor may not be
necessary. Otherwise an input filter capacitor in the
range of 1µF to 10µF will ensure adequate filtering.
GND is the negative reference for all voltages. This
current that flows in the ground connection is very low
(TYP 550µA) and has minimal variation over all load
conditions.
VOUT is the regulator output voltage connection used to
power the load. An output capacitor of 4.7µF is used to
provide the necessary phase compensation, thereby
preventing oscillation. The capacitor also helps to
minimize the peak output disturbance during power
supply changeover.
When V falls below V , then V will be used to
CC
OUT
OUT
provide the necessary quiescent current for the internal
reference circuits. This ensures excellent start-up
characteristics for the regulator.
DRIVE is an active LOW logic output intended to be
used as the control signal for driving an external PFET
whenever the regulator is disabled. This will allow the
voltage at VOUT to be powered from an auxiliary supply
voltage (3.3V).
The Drive pin is pulled HIGH to VCC whenever the
regulator is enabled, this ensures the auxiliary remains
isolated during normal regulator operation.
The output current sinking ability of this logic signal is
equivalent to a 100W resistor. The current sourcing
ability is equivalent to a 4kΩ resistor.
NC pins are electrically isolated from the internal
circuitry. These pins can be connected to any external
voltage level without impacting the device functionality.
Pin
1
6, 7
8
4
2, 3, 5
Symbol
VCC
VOUT
DRIVE
GND
NC
PIN FUNCTIONS
Description
Positive (5V) supply input for regulator. (VCC > VCCSEL)
Continuous output voltage (3.3V) is derived from either the internal regulator or low impedance
switch connected to the auxiliary supply input.
Output drive signal to control external MOSFET switch
Negative reference for all voltages
Unconnected pin which is electrically isolated from internal circuitry.
VCC
VDESELECT
4.1V
GND
+
–
VREF
3.3V
ENABLE
+
–
DRIVE
VOUT
3.3V
300mA
Simplified Electrical Schematic
© 2001 California Micro Devices Corp. All rights reserved. SmartOR™ is a trademark of California Micro Devices Corp
215 Topaz Street, Milpitas, California 95035 Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3/5/2001
3
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