PRELIMINARY
CALIFORNIA MICRO DEVICES
CM3151
Micropower, 500mA / 3.3V SmartOR
TM
Regulator with Drive
Features
3.3V regulated output up to 500mA in MSOP-8
package (150mA in SOT-23-6 package)
Automatic Detection of V
IN
Input Supply
Drive Output Logic to Control External PFET
Switch
<1 A quiescent current when V
IN
not present
“Zero” current in Shutdown mode
Built-In Hysteresis during Supply Selection
Thermal Overload Protection
Current Limiting Protection
Controller operates from either V
IN
or V
OUT
Pin Diagram
Applications
USB bus-powered handheld devices
PCI Adapter Cards
Product Description
TM
In
Package
Pins
8
6
Style
Power MSOP-8
SOT-23-6
The SmartOR CM3151 is a low dropout regulator
that delivers up to 500mA of load current in the
MSOP-8 package at a fixed 3.3V output. Continuous
output current is only limited by the package and the
layout (150mA max current in the SOT-23-6
package). An internal threshold level (typically 3.9V)
is used to prevent the regulator from being operated
below dropout voltage. The device continuously
monitors the input supply and will automatically
disable the regulator when V
IN
falls below the
threshold level. When the regulator is disabled, the
control signal “Drive” (Active Low) is enabled, which
allows an external PMOS switch to power the load
from a battery. When Vin is not present, the device
only draws less than 1 A from the output preventing
from discharging the battery.
When V
IN
is restored to a level above the select
threshold, the control signal for the external PMOS
switch is disabled and the regulator is once again
enabled.
The Enable input allows to shutdown the regulator
as well as sets the Drive signal “High” disabling the
external PMOS switch.
The CM3151 is available in an 8-pin MSOP
thermally enhanced package, or 6-pin SOT23 ideal
for space critical applications.
© 2004 California Micro Devices Corp. All rights reserved.
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Simplified Electrical Schematic
STANDARD PART ORDERING INFORMATION
Ordering Part Number
Tubes
Tape & Reel
Part Marking
www.calmicro.com
Typical Application Circuit (for MSOP-8)
C0590899
6/29/04
430 N. McCarthy Blvd., Milpitas, California 95035
1
PRELIMINARY
CALIFORNIA MICRO DEVICES
Absolute Maximum Ratings
Parameter
Rating
ESD Protection (HBM)
2000
V
CC
Input Voltage
+ 6.0, Gnd - 0.5
Drive Logic Voltage
V
CC
+ 0.5, Gnd - 0.5
Temperature: Storage
- 40 to +150
Operating Ambient
0 to +70
Operating Junction
0 to +125
1
Power Dissipation (MSOP-8)
Internally limited
(SOT23-6)
Operating Conditions
Range
5.0 ± 0.5
0 to +70
0 to 500
10 ± 20%
Unit
V
V
V
- C
CM3151
W
Electrical Operating Characteristics (over operating conditions unless specified otherwise)
Symbol Parameter
Conditions
MIN
TYP
MAX
V
OUT
Regulator Output Voltage
500mA > I
LOAD
> 0mA
3.135
3.30
3. 465
V
CCSEL
Select Voltage
4.30
Regulator Enabled
4.40
V
CCDES
Deselect Voltage
3.80
3.90
Regulator Disabled
2
V
CCHYST
Hysteresis Voltage
0.40
Hysteresis
I
S/C
Short Circuit Output Current V
CC
= 5V, V
OUT
= 0V
700
I
RCC,
V
R LOAD
V
R LINE
I
GND
V
CC
Pin Reverse Leakage
Load Regulation
Line Regulation
Ground Current
3
V
OUT
= 3.3V, V
CC
= 0V
V
CC
= 5V, I
LOAD
= 50mA to 500mA
V
CC
= 4.5V to 5.5V, I
LOAD
= 5mA
5
75
2
50
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Drive pull-up resistance
Drive pulldown resistance
Drive High Delay
Drive Low Delay
Shutdown temperature
Thermal hysteresis
EN = low (Disabled mode)
EN = high and V
CC
< V
OUT
V
CC
= 5V, I
LOAD
= 1mA
V
CC
= 5V, I
LOAD
= 500mA
R
PULLUP
to V
CC
, V
CC
> V
CCSEL
R
PULLDOWN
to GND , V
CCDES
> V
CC
C
DRIVE
= 1nF, V
CC
t
RISE
< 100ns
C
DRIVE
= 1nF, V
CC
t
FALL
< 100ns
0.5
1
1
120
130
100
200
1.0
0.2
400
400
150
20
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
Parameter
V
CC
Temperature (Ambient)
Load Current
C
EXT
Unit
V
C
mA
F
UNIT
V
V
mA
A
mV
mV
A
In
R
OH
R
OL
t
DH
t
DL
s
C
T
DISABLE
T
HYST
Note 1: The SOIC package used is thermally enhanced through the use of a fused integral leadframe. The power rating is based on a printed
circuit board heat spreading capability equivalent to 2 square inches of copper connected to the GND pins. Typical multi-layer boards using
power plane construction will provide this heat spreading ability without the need for additional dedicated copper area. (Please consult with
factory for thermal evaluation assistance)
Note 2: The hysteresis defines the maximum level of acceptable disturbance on V
CC
during switching. It is recommended that the V
CC
source
impedance be kept below 0.25 to ensure the switching disturbance remains below the hysteresis during select/deselect transitions. An
input capacitor may be required to help minimize the switching transient.
Note 3: Ground pin current consists of controller current and regulator current if enabled. The controller always draws current from either V
CC
or
V
OUT
, whichever is greater. All regulator current is supplied exclusively from V
CC
.
© 2004 California Micro Devices Corp. All rights reserved
430 N. McCarthy Blvd., Milpitas, California 95035
2
PRELIMINARY
CALIFORNIA MICRO DEVICES
Interface Signals
V
CC
is the power source for the internal regulator
and is monitored continuously by an internal
controller circuit.
Whenever V
CC
exceeds V
CCSEL
(4.30V typically), the
internal regulator will be enabled and deliver a fixed
3.3V at V
OUT
. When V
CC
falls below V
CCDES
(3.90V
typically) the regulator will be disabled.
During a V
CC
power up sequence, there will be an
effective step increase in V
CC
line current when the
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 V
CC
pin. The
magnitude of the disturbance will be directly
proportional to the effective power supply source
impedance being delivered to the V
CC
input.
To prevent chatter during Select and Deselect
transitions, a built-in hysteresis voltage of 250mV
has been incorporated. It is recommended that the
power supply connected to the V
CC
input should
have a source resistance of less than 0.5 to
minimize the event of chatter during the
enabling/disabling of the regulator.
An input filter capacitor in close proximity to the V
CC
pin will reduce the effective source impedance and
help minimize any disturbances. If the V
CC
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 1uF to 10uF will
ensure adequate filtering.
CM3151
V
OUT
is the regulator output voltage connection
used to power the load. An output capacitor of ten
microfarads 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
CC
falls below V
OUT
, then V
OUT
will be used to
provide the necessary quiescent current for the
internal reference circuits. This ensures excellent
start-up characteristics for the regulator.
GND
is the negative reference for all voltages.
Symbol
V
CC
GND
V
OUT
Drive
EN
BYP
© 2004 California Micro Devices Corp. All rights reserved
430 N. McCarthy Blvd., Milpitas, California 95035
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Pin Functions
Enable input for the regulator.
Bypass capacitor input for the regulator (only available in the SOT23-6 package version).
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
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
allows the voltage at V
OUT
to be powered from an
auxiliary supply voltage (3.3V).
The Drive pin is pulled High to V
CC
whenever the
regulator is enabled, this ensures the auxiliary
remains isolated during normal regulator operation.
EN
is the enable input. When set to a logic High, the
regulator is enabled. When set to a logic Low, the
regulator is disabled and the Drive signal is set to a
high level, which turns off the external PFET switch.
Therefore when Enable is set low (disabled mode),
both the regulator and the switch are turned off.
In
BYP
is the bypass capacitor input pin. This pin is
only available in the SOT23-6 package version. It
allows to connect an external capacitor (typically
10nF) to further reduce the noise on the regulator
output.
Description
Positive Supply input for the regulator. When V
CC
falls below 3.9V the regulator is disabled.
Negative reference for all voltages.
Regulator voltage output (3.3V) regulator when V
CC
is present. When V
CC
is not present, the voltage
on V
OUT
is used to bias the internal references.
CMOS Logic Output intended to control external PMOS switch for selecting an auxiliary voltage supply
when V
CC
is not present.
3
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