NSC LMS5258

LMS5258
150mA, µCap, Low Dropout Voltage Regulator with
Power Good
General Description
Features
The LMS5258 is a µCap, precise CMOS voltage regulator
with power good output.
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It provides up to 150mA and consumes a typical of 10nA in
shutdown mode. The LMS5258 output stage is designed
with a push pull output for faster transient response.
The LMS5258 is optimized to work with low value, low cost
ceramic capacitors. The output typically require only 1µF of
output capacitance for stability. The enable pin can be tied to
VIN for easy device layout.
The LMS5258 is designed for portable, battery powered
equipment applications with small space requirements.
The LMS5258 is available in a 5-pin SOT-23 package. Performance is specified for the −40˚C to +125˚C temperature
range and is available in a fixed 1.2V. For other output
voltage options, please contact National Semiconductor.
Power good indicator
Stability with low ESR capacitors
Low ground current: 120µA
150mA output current
"Zero" shutdown mode current
Fast transient response
Auto Discharge
Thermal shutdown
Current limiting
TTL-Logic-controlled enable input
Pin-to-pin replacement for Mic™ 5258
Applications
n Processor power-up sequencing
n Laptop, notebook and palm top computer
n PCMCIA VCC and VPP regulation switching
Typical Application
20042419
Pin Description
Pin Number
Pin Name
Pin Function
1
VIN
Input Voltage
2
GND
3
EN
Enable Input Logic,
Logic High = Enabled
Logic Low = Shutdown
(Do not leave open)
4
PG
Power Good Output
5
VOUT
Output Voltage
© 2003 National Semiconductor Corporation
DS200424
Ground
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LMS5258 150mA, µCap, Low Dropout Voltage Regulator with Power Good
February 2003
LMS5258
Connection Diagram
SOT23-5
20042421
Top View
Ordering Information
Package
5-Pin SOT-23
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Part Number
Package Marking
LMS5258MF-1.2
LF9B
LMS5258MFX-1.2
2
Transport Media
1k Units Tape and Reel
3k Units Tape and Reel
NSC
Drawing
MF05A
Operating Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltages
VIN
2.7V to 6V
VEN
ESD Tolerance (Note 2)
Human Body Model
2000V
Junction Temperature
150˚C
VIN, VOUT, VEN
Storage Temperature Range
−40˚C to +125˚C
−65˚C to 150˚C
Package Themal Resistance
−0.3 TO 6.5V
Infrared or Convection (20 sec)
0V to VIN
Junction Temp. Range (Note 3)
SOT23-5
Soldering Information
Wave Soldering (10 sec)
LMS5258
Absolute Maximum Ratings
235˚C/W
235˚C
260˚C (lead temp)
Electrical Characteristics
Unless otherwise specified, all limits guaranteed for TJ = 25˚C, VIN = 2.7V, IL = 100µA, COUT = 1µF, VEN ≥ 2.0V. Boldface
limits apply over the entire operating temperature range, −40˚C to 125˚C.
Symbol
Parameter
Conditions
VO
Output Voltage Accuracy
∆VO/VO
Line Regulation
VIN = 2.7V to 6V
∆VO/VO
Load Regulation
IL = 0.1mA to 150mA (Note 6)
IQ
Quiescent Current
VEN ≤ 0.4V (Shutdown), PG = NC
IGND
Ground Pin Current (Note 5) VEN ≥ 2.0V (active),
VIN = 6V, IL = 0mA
Min
(Note 5)
Typ
(Note 4)
-3
-4
−0.3
1
Max
(Note 5)
Units
3
4
%
0.3
%
4
%
.01
1
µA
120
180
µA
IL = 150mA, VEN ≥ 2.0V (active),
VIN = 6V
160
225
62
dB
350
mA
150
˚C
PSRR
Power Supply Rejection
f = 120HZ, COUT = 4.7µF,
IL = 150mA
ILIMIT
Current Limit
VOUT = 0V
160
Thermal Protection
Thermal Shutdown
Temperature
Enable Input
VIL
Enable Input Voltage Level
VIH
IIL
Logic Low (off), VIN = 5.5V
Logic High (on), VIN = 5.5V
Enable Input Current
IIH
0.4
2
V
V
VIL ≤ 0.4V, VIN = 5.5V
0.01
µA
VIH ≥ 2.0V, VIN = 5.5V
0.01
µA
Power Good
VPG
Low Threshold
% of VOUT (PG ON)
89
High Threshold
% of VOUT (PG OFF)
VOL
PG Output Logic-Low
Voltage
Ipowergood = 100µA, Fault
Condition
0.02
IPG
Power Good Leakage
Current
Power Good Off, VPG = 5.5V
0.01
VPG Delay
Delay Time to Power Good
See Timing Diagram
97
1
0.1
%
V
µA
5
ms
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: Human body model, 1.5kΩ in series with 100pF.
Note 3: The maximum power dissipation is a function of TJ(MAX) , θJA, and TA. The maximum allowable power dissipation at any ambient temperature
is PD = (TJ(MAX)–T A)/θJA. All numbers apply for packages soldered directly into a PC board.
Note 4: Typical Values represent the most likely parametric norm.
Note 5: All limits are guaranteed by testing or statistical analysis.
Note 6: Regulation is measured at constant junction temperature using low duty cycle pulse testing.
Note 7: Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current.
3
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LMS5258
Timing Diagram
20042415
Block Diagram
20042420
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4
Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA =
Ground Current vs. Output Current
Ground Current vs. Input Voltage
20042402
20042401
Ground Current vs. Temperature
Short Circuit Current vs. Temperature (VIN = 3.3V)
20042404
20042403
Short Circuit Current vs. Input Voltage
Power Good Delay vs. Input Voltage (IL = 100µA)
20042405
20042406
5
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LMS5258
Typical Performance Characteristics
25˚C and powergood pull up resistor = 47kΩ.
LMS5258
Typical Performance Characteristics Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA =
25˚C and powergood pull up resistor = 47kΩ. (Continued)
Power Good Delay vs. Temperature (VIN = 3.3V)
Output Voltage vs. Temperature
20042407
20042408
Output Voltage vs. Input Voltage
Output Voltage vs. Output Current
20042411
20042409
Enable Voltage vs. Input Voltage
Enable Voltage vs. Temperature
20042422
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20042423
6
Power Good Pull-Up Resistor vs. Power Good
Voltage Noise vs. Frequency
20042412
20042416
PSRR vs. Frequency
Power On Reset Delay Time
20042414
20042413
7
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LMS5258
Typical Performance Characteristics Unless otherwise specified, VIN = 3.3V, COUT = 1µF, TA =
25˚C and powergood pull up resistor = 47kΩ. (Continued)
LMS5258
When a fault condition and an undervoltage detection occur,
the output of the power good pin goes low. The power good
output comes back up once the output has reached 97% of
its nominal value and 1ms to 5ms delay has passed , see
timing diagram.
The LMS5258 internal circuit monitors overcurrent, temperature and falling output voltage. If one of these conditions is
flaged that indicates a fault condition.
Application Notes
LMS5258 is a linear regulator designed to be used with a low
ESR, low cost ceramic capacitors.
EXTERNAL CAPACITORS
The LMS5258 regulator requires an output capacitor to
maintain stability. The capacitor must be at least 1µF or
greater. The capacitor can be low-ESR ceramic chip capacitor, however for improved capacitance over temperature,
tantalum capacitors can be used.
The flaged condition output is fed into an onchip delay circuit
that drives the open drain output transistor.
A 1µF input capacitor is recommended when the supply
capacitance is more than 10 inches away from the device, or
when the supply is a battery.
X7R dielectric ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic
capacitors. Z5U and Y5V dielectric capacitors change value
by as much 50% and 60% respectively over their operating
temperature range. To use a ceramic chip capacitor with Y5V
dielectric, the value must be much higher than an X7R
ceramic or a tantalum capacitor to ensure the same minimum capacitance value over the operating temperature
range. Tantalum capacitors have a very stable dielectric
(10% over their operating temperature range) and can also
be used with this device.
TRANSIENT RESPONSE
The LMS5258 implements a unique output stage to dramatically improve transient response recovery time. The output is
a totem-pole configuration with a P-channel MOSFET pass
device and a N-channel MOSFET clamp. The N-channel
clamp is a significantly smaller device that prevents the
output voltage from overshooting when a heavy load is
removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load to light load.
THERMAL BEHAVIOR
The LMS5258 regulator has internal thermal shutdown to
protect the device from over heating. Under all operating
conditions, the maximum junction temperature of the
LMS5258 must be below 125˚C. Maximum power dissipation
can be calculated based on the output current and the
voltage drop across the part. The maximum power dissipation is
PD(MAX) = (TJ(MAX)–TA)/θJA
θJA is the junction-to-ambient thermal resistance, 235˚C/W
for the LMS5258 in the SOT23-5 package. TA is the maximum ambient temperature T J(MAX) is the maximum junction
temperature of the die, 125˚C.
ENABLE/SHUTDOWN
The LMS5258 has an active high enable pin that allows the
regulator to be disabled. Applying a Logic Level low ( < 0.4 V)
to the Shutdown pin will cause the output to turn off, in this
state current consumed by the regulator goes nearly to zero.
Applying a logic level high ( > 2.0) enables the output voltage.
The enable/shutdown pin can’t be left floating; a floating
enable pin may cause an indeterminate state on the output.
When operating the LMS5258 at room temperature, the
maximum power dissipation is 425mW.
The actual power dissipated by the regulator is
PD = (VIN – VOUT) IL + VIN IGND
Substituting PD(MAX), determined above, for PD and solving
for the operating condition that are critical to the application
will give the maximum operating conditions for the regulator
circuit. To prevent the device from entering thermal shutdown, maximum power dissipation cannot be exceeded.
ACTIVE SHUTDOWN
The LMS5258 designed with a N-channel MOSFET that acts
as a shutdown clamp. The N-channel turns on when the
device is disabled to allow the output capacitor and load to
discharge.
POWER GOOD
The power good output is an open-drain output. It is designed essentially to work as a power-on reset generator
once the regulated voltage was up and/ or a fault condition.
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8
inches (millimeters)
5-Pin SOT23-5
NSC Package Number MF05A
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
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whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
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LMS5258 150mA, µCap, Low Dropout Voltage Regulator with Power Good
Physical Dimensions
unless otherwise noted