LP3988
Micropower, 150mA Ultra Low-Dropout CMOS Voltage
Regulator With Power Good
General Description
The LP3988 is a 150mA low dropout regulator designed
specially
to
meet
requirements
of
Portable
battery-
applications. The LP3988 is designed to work with a space
saving, small 1F ceramic capacitor. The LP3988 features
an Error Flag output that indicates a faulty output condition.
The LP3988's performance is optimized for battery powered
systems to deliver low noise, extremely low dropout voltage
and low quiescent current. Regulator ground current in-
creases only slightly in dropout, further prolonging the bat-
tery life.
Power supply rejection is better than 60 dB at low frequen-
cies and starts to roll off at 10 kHz. High power supply
rejection is maintained down to lower input voltage levels
common to battery operated circuits.
The device is ideal for mobile phone and similar battery
powered wireless applications. It provides up to 150 mA,
from a 2.5V to 6V input, consuming less than 1 A in disable
mode and has fast turn-on time less than 200s.
The LP3988 is available 5 pin SOT-23 package and 5 bump
thin micro SMD package. Performance is specified for -40C
to +125C temperature range and is available in 1.85, 2.5,
2.6, 2.85, 3.0 and 3.3V output voltages.
Key Specifications
n
2.5 to 6.0V input range
n
150mA guaranteed output
n
40dB PSRR at 10kHz
n
1 A quiescent current when shut down
n
Fast Turn-On time: 100 s (typ.)
n
80 mV typ dropout with 150mA load
n
-40 to +125C junction temperature range for operation
n
1.85V, 2.5V, 2.6V, 2.85V, 3.0V, and 3.3V
Features
n
5 bump thin micro SMD package
n
SOT-23-5 package
n
Power-good flag output
n
Logic controlled enable
n
Stable with ceramic and high quality tantalum capacitors
n
Fast turn-on
n
Thermal shutdown and short-circuit current limit
Applications
n
CDMA cellular handsets
n
Wideband CDMA cellular handsets
n
GSM cellular handsets
n
Portable information appliances
n
Tiny 3.3V
5% to 2.85V, 150mA converter
Typical Application Circuit
20020502
August 2004
LP3988
Micropower
,
150mA
Ultra
Low-Dropout
CMOS
V
oltage
Regulator
W
ith
Power
Good
2004 National Semiconductor Corporation
DS200205
www.national.com
Absolute Maximum Ratings
(Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
V
IN
-0.3 to 6.5V
V
OUT
, V
EN
, PowerGood(applies
only to micro SMD)
-0.3V to (V
IN
+0.3V),
with 6V max
Junction Temperature
150C
Storage Temperature
-65C to +150C
Lead Temp, Pad Temp.
235C
Power Dissipation (Note 3)
SOT23-5
micro SMD
364mW
355mW
ESD Rating (Note 4)
Human Body Model
2kV
Machine Model
SOT23-5 (Note 13)
150V
micro SMD
200V
Operating Ratings
(Notes 1, 2)
V
IN
(Note 15)
2.5V to 6V
V
OUT
, V
EN
0 to V
IN
Junction Temperature
-40C to +125C
Junction-to-Ambient Thermal
Resistance (
JA
)
SOT23-5
micro SMD
220
o
C/W
255
o
C/W
Maximum Power Dissipation (Note 5)
SOT23-5
micro SMD
250mW
244mW
Electrical Characteristics
Unless otherwise specified: V
EN
= 1.8V, V
IN
= V
OUT
+ 0.5V, C
IN
= 1 F, I
OUT
= 1mA, C
OUT
= 1 F. Typical values and limits
appearing in standard typeface are for T
J
= 25C. Limits appearing in boldface type apply over the entire junction temperature
range for operation, -40C to +125C. (Note 6) (Note 7)
Symbol
Parameter
Conditions
Typ
Limit
Units
Min
Max
V
OUT
Output Voltage
Tolerance
-20C % T
J
% 125C, SOT23-5
-40C % T
J
% 125C, SOT23-5
-2
-3
-3.5
2
3
3.5
% of
V
OUT(nom)
-40C % T
J
% 125C, micro SMD
-3
3
Line Regulation Error
V
IN
= V
OUT (NOM)
+ 0.5V to 6.0V
-0.15
-0.2
0.15
0.2
%/V
Load Regulation Error
(Note 8)
I
OUT
= 1 mA to 150 mA
0.005
0.007
%/mA
PSRR
Power Supply Rejection Ratio
V
IN
= V
OUT(nom)
+ 1V,
f = 1 kHz,
I
OUT
= 50 mA (Figure 3)
65
dB
V
IN
= V
OUT(nom)
+ 1V,
f = 10 kHz,
I
OUT
= 50 mA (Figure 3)
45
I
Q
Quiescent Current
V
EN
= 1.4V, I
OUT
= 0 mA
85
120
A
V
EN
= 1.4V, I
OUT
= 0 to 150 mA
140
200
V
EN
= 0.4V
0.003
1.0
Dropout Voltage (Note 9)
I
OUT
= 1 mA
1
5
mV
I
OUT
= 150 mA
80
115
150
I
SC
Short Circuit Current Limit
(Note 10)
600
mA
e
n
Output Noise Voltage
BW = 10 Hz to 100 kHz,
C
OUT
= 1F
220
Vrms
C
OUT
Output Capacitor
Capacitance (Note 11)
1
20
F
ESR (Note 11)
5
500
m
TSD
Thermal Shutdown Temperature
160
C
Thermal Shutdown Hysteresis
20
C
Enable Control Characteristics (Note 12)
I
EN
Maximum Input Current at EN
V
EN
= 0 and V
IN
= 6.0V
0.1
A
LP3988
www.national.com
4
Electrical Characteristics
(Continued)
Unless otherwise specified: V
EN
= 1.8V, V
IN
= V
OUT
+ 0.5V, C
IN
= 1 F, I
OUT
= 1mA, C
OUT
= 1 F. Typical values and limits
appearing in standard typeface are for T
J
= 25C. Limits appearing in boldface type apply over the entire junction temperature
range for operation, -40C to +125C. (Note 6) (Note 7)
Symbol
Parameter
Conditions
Typ
Limit
Units
Min
Max
V
IL
Logic Low Input threshold
V
IN
= 2.5V to 6.0V
0.5
V
V
IH
Logic High Input threshold
V
IN
= 2.5V to 6.0V
1.2
V
Power Good
V
THL
V
THH
Power Good
Low threshold
High Threshold
% of V
OUT
(PG ON) Figure 2
% of V
OUT
(PG OFF) Figure 2 (Note
14)
93
95
90
92
95
98
%
V
OL
PG Output Logic Low Voltage
I
PULL-UP
= 100A, fault condition
0.02
0.1
V
I
PGL
PG Output Leakage Current
PG Off, V
PG
= 6V
0.02
A
T
ON
Power Good Turn On time,
(Note 9)
V
IN
= 4.2V
10
s
T
OFF
Power Good Turn Off time,
(Note 9)
V
IN
= 4.2V
10
s
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device
is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical
Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: The Absolute Maximum power dissipation depends on the ambient temperature and can be calculated using the formula:
P
D
= (T
J
- T
A
)/
JA
where T
J
is the junction temperature, T
A
is the ambient temperature, and
JA
is the junction-to-ambient thermal resistance. The 364mW rating appearing under
Absolute Maximum Ratings for the SOT23-5 package results from substituting the Absolute Maximum junction temperature, 150C, for T
J
, 70C for T
A
, and 220C/W
for
JA
. More power can be dissipated safely at ambient temperatures below 70C . Less power can be dissipated safely at ambient temperatures above 70C. The
Absolute Maximum power dissipation can be increased by 4.5mW for each degree below 70C, and it must be derated by 4.5mW for each degree above 70C. Same
principle applies to the micro SMD package.
Note 4: The human body model is 100pF discharged through 1.5k
resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each
pin.
Note 5: Like the Absolute Maximum power dissipation, the maximum power dissipation for operation depends on the ambient temperature. The 250mW rating
appearing under Operating Ratings for the SOT23-5 package results from substituting the maximum junction temperature for operation, 125C, for T
J
, 70C for T
A
,
and 220C/W for
JA
into (Note 3) above. More power can be dissipated at ambient temperatures below 70C . Less power can be dissipated at ambient
temperatures above 70C. The maximum power dissipation for operation can be increased by 4.5mW for each degree below 70C, and it must be derated by 4.5mW
for each degree above 70C. Same principle applies to the micro SMD package.
Note 6: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with T
J
= 25C or correlated using
Statistical Quality Control (SQC) methods. All hot and cold limits are guaranteed by correlating the electrical characteristics to process and temperature variations
and applying statistical process control.
Note 7: The target output voltage, which is labeled V
OUT(nom)
, is the desired voltage option.
Note 8: An increase in the load current results in a slight decrease in the output voltage and vice versa.
Note 9: Dropout voltage is the input-to-output voltage difference at which the output voltage is 100mV below its nominal value.
Note 10: Short circuit current is measured on input supply line after pulling down V
OUT
to 95% V
OUT(nom)
.
Note 11: Guaranteed by design. The capacitor tolerance should be
30% or better over the full temperature range. The full range of operating conditions such as
temperature, DC bias and even capacitor case size for the capacitor in the application should be considered during device selection to ensure this minimum
capacitance specification is met. X7R capacitor types are recommended to meet the full device temperature range.
Note 12: Turn-on time is time measured between the enable input just exceeding V
IH
and the output voltage just reaching 95% of its nominal value.
Note 13: 100V machine model for Power-good flag, pin 4.
Note 14: The low and high thresholds are generated together. Typically a 2.6% difference is seen between these thresholds.
Note 15: The minimum V
IN
is dependant on the device output option.
For Vout
(NOM)
<
2.5V, V
IN(MIN)
will equal 2.5V. For Vout
(NOM)
>
= 2.5V, V
IN(MIN)
will equal Vout
(NOM)
+ 200mV.
LP3988
www.national.com
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