LP38691/LP38693
500mA Low Dropout CMOS Linear Regulators
Stable with Ceramic Output Capacitors
General Description
The LP38691/3 low dropout CMOS linear regulators provide
tight output tolerance (2.0% typical), extremely low dropout
voltage (250 mV
@
500mA load current, V
OUT
= 5V), and
excellent AC performance utilizing ultra low ESR ceramic
output capacitors.
The low thermal resistance of the LLP, SOT-223 and T0-252
packages allow the full operating current to be used even in
high ambient temperature environments.
The use of a PMOS power transistor means that no DC base
drive current is required to bias it allowing ground pin current
to remain below 100 A regardless of load current, input
voltage, or operating temperature.
Dropout Voltage: 250 mV (typ)
@
500mA (typ. 5V out).
Ground Pin Current: 55 A (typ) at full load.
Precision Output Voltage: 2.0% (25C) accuracy.
Features
n
2.0% output accuracy (25C)
n
Low dropout voltage: 250 mV
@
500mA (typ, 5V out)
n
Wide input voltage range (2.7V to 10V)
n
Precision (trimmed) bandgap reference
n
Guaranteed specs for -40C to +125C
n
1A off-state quiescent current
n
Thermal overload protection
n
Foldback current limiting
n
T0-252, SOT-223 and 6-Lead LLP packages
n
Enable pin (LP38693)
Applications
n
Hard Disk Drives
n
Notebook Computers
n
Battery Powered Devices
n
Portable Instrumentation
Typical Application Circuits
20126501
20126502
Note: * Minimum value required for stability.
**LLP package devices only.
PRELIMINARY
January 2005
LP38691/LP38693
500mA
Low
Dropout
CMOS
Linear
Regulators
Stable
with
Ceramic
Output
Capacitors
2005 National Semiconductor Corporation
DS201265
www.national.com
Connection Diagrams
20126503
TO-252, Top View
LP38691DT-X.X
20126504
SOT-223, Top View
LP38693MP-X.X
20126505
6-Lead LLP, Bottom View
LP38691SD-X.X
20126506
6-Lead LLP, Bottom View
LP38693SD-X.X
Pin Description
PIN
DESCRIPTION
V
IN
This is the input supply voltage to the regulator. For LLP devices, both V
IN
pins must be tied
together for full current operation (250mA maximum per pin).
GND
Circuit ground for the regulator. This is connected to the die through the lead frame, and also
functions as the heat sink when the large ground pad is soldered down to a copper plane.
SNS
Output sense pin allows remote sensing at the load which will eliminate the error in output
voltage due to voltage drops caused by the resistance in the traces between the regulator and
the load. This pin must be tied to V
OUT
.
V
EN
The enable pin allows the part to be turned ON and OFF by pulling this pin high or low.
V
OUT
Regulated output voltage
Ordering Information
Order Number
Package Marking
Package Type
Package Drawing
Supplied As
LP38691SD-1.8
L118B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38691SD-2.5
L119B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38691SD-3.3
L120B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38691SD-5.0
L121B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38691DT-1.8
LP38691DT-1.8
TO-252
TD03B
Available Soon
LP38691DT-2.5
LP38691DT-2.5
TO-252
TD03B
Available Soon
LP38691DT-3.3
LP38691DT-3.3
TO-252
TD03B
Available Soon
LP38691DT-5.0
LP38691DT-5.0
TO-252
TD03B
Available Soon
LP38693SD-1.8
L128B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38693SD-2.5
L129B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38693SD-3.3
L130B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38693SD-5.0
L131B
6-Lead LLP
SDE06A
1000 Units Tape and Reel
LP38693MP-1.8
LJVB
SOT-223
MP05A
1000 Units Tape and Reel
LP38691/LP38693
www.national.com
2
Ordering Information
(Continued)
Order Number
Package Marking
Package Type
Package Drawing
Supplied As
LP38693MP-2.5
LJXB
SOT-223
MP05A
1000 Units Tape and Reel
LP38693MP-3.3
LJYB
SOT-223
MP05A
1000 Units Tape and Reel
LP38693MP-5.0
LJZB
SOT-223
MP05A
1000 Units Tape and Reel
LP38691SDX-1.8
L118B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38691SDX-2.5
L119B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38691SDX-3.3
L120B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38691SDX-5.0
L121B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38691DTX-1.8
LP38691DT-1.8
TO-252
TD03B
Available Soon
LP38691DTX-2.5
LP38691DT-2.5
TO-252
TD03B
Available Soon
LP38691DTX-3.3
LP38691DT-3.3
TO-252
TD03B
Available Soon
LP38691DTX-5.0
LP38691DT-5.0
TO-252
TD03B
Available Soon
LP38693SDX-1.8
L128B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38693SDX-2.5
L129B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38693SDX-3.3
L130B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38693SDX-5.0
L131B
6-Lead LLP
SDE06A
4500 Units Tape and Reel
LP38693MPX-1.8
LJVB
SOT-223
MP05A
2000 Units Tape and Reel
LP38693MPX-2.5
LJXB
SOT-223
MP05A
2000 Units Tape and Reel
LP38693MPX-3.3
LJYB
SOT-223
MP05A
2000 Units Tape and Reel
LP38693MPX-5.0
LJZB
SOT-223
MP05A
2000 Units Tape and Reel
LP38691/LP38693
www.national.com
3
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
-65C to +150C
Lead Temp. (Soldering, 5 seconds)
260C
ESD Rating (Note 3)
2 kV
Power Dissipation (Note 2)
Internally Limited
V(max) All pins (with respect to GND)
-0.3V to 12V
I
OUT
Internally Limited
Junction Temperature
-40C to +150C
Operating Ratings
V
IN
Supply Voltage
2.7V to 10V
Operating Junction
Temperature Range
-40C to +125C
Electrical Characteristics
Limits in standard typeface are for T
J
= 25C, and limits in boldface type apply
over the full operating temperature range. Unless otherwise specified: V
IN
= V
OUT
+ 1V, C
IN
= C
OUT
= 10 F, I
LOAD
= 10mA.
Min/Max limits are guaranteed through testing, statistical correlation, or design.
Symbol
Parameter
Conditions
MIN
TYP
(Note 4)
MAX
Units
V
O
Output Voltage Tolerance
-2.0
2.0
%V
OUT
100 A
<
I
L
<
0.5A
V
O
+ 1V
V
IN
10V
-4.0
4.0
V
O
/
V
IN
Output Voltage Line Regulation
(Note 6)
V
O
+ 0.5V
V
IN
10V
I
L
= 25mA
0.03
0.1
%/V
V
O
/
I
L
Output Voltage Load Regulation
(Note 7)
1 mA
<
I
L
<
0.5A
V
IN
= V
O
+ 1V
1.8
5
%/A
V
IN
- V
OUT
Dropout Voltage (Note 8)
(V
O
= 2.5V)
I
L
= 0.1A
I
L
= 0.5A
80
430
145
725
mV
(V
O
= 3.3V)
I
L
= 0.1A
I
L
= 0.5A
65
330
110
550
(V
O
= 5V)
I
L
= 0.1A
I
L
= 0.5A
45
250
100
450
I
Q
Quiescent Current
V
IN
10V, I
L
=100 A - 0.5A
55
100
A
V
EN
0.4V, (LP38693 Only)
0.001
1
I
L
(MIN)
Minimum Load Current
V
IN
- V
O
4V
100
I
FB
Foldback Current Limit
V
IN
- V
O
>
5V
350
mA
V
IN
- V
O
<
4V
850
PSRR
Ripple Rejection
V
IN
= V
O
+ 2V(DC), with 1V(p-p)
/ 120Hz Ripple
55
dB
T
SD
Thermal Shutdown Activation
(Junction Temp)
160
C
T
SD
(HYST)
Thermal Shutdown Hysteresis
(Junction Temp)
10
LP38691/LP38693
www.national.com
4
Electrical Characteristics
Limits in standard typeface are for T
J
= 25C, and limits in boldface type apply
over the full operating temperature range. Unless otherwise specified: V
IN
= V
OUT
+ 1V, C
IN
= C
OUT
= 10 F, I
LOAD
= 10mA.
Min/Max limits are guaranteed through testing, statistical correlation, or design. (Continued)
Symbol
Parameter
Conditions
MIN
TYP
(Note 4)
MAX
Units
e
n
Output Noise
BW = 10Hz to 10kHz
V
O
= 3.3V
0.7
V/
V
O
(LEAK)
Output Leakage Current
V
O
= V
O
(NOM) + 1V
@
10V
IN
0.5
12
A
V
EN
Enable Voltage (LP38693 Only)
Output = OFF
0.4
V
Output = ON, V
IN
= 4V
1.8
Output = ON, V
IN
= 6V
3.0
Output = ON, V
IN
= 10V
4.0
I
EN
Enable Pin Leakage (LP38693
Only)
V
EN
= 0V or 10V, V
IN
= 10V
-1
0.001
1
A
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Operating ratings indicate conditions for which the device
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see Electrical Characteristics. Specifications do not
apply when operating the device outside of its rated operating conditions.
Note 2: At elevated temperatures, device power dissipation must be derated based on package thermal resistance and heatsink values (if a heatsink is used). The
junction-to-ambient thermal resistance (
J-A
) for the TO-252 is approximately 90C/W for a PC board mounting with the device soldered down to minimum copper
area (less than 0.1 square inch). If one square inch of copper is used as a heat dissipator for the TO-252, the
J-A
drops to approximately 50C/W. The SOT-223
package has a
J-A
of approximately 125C/W when soldered down to a minimum sized pattern (less than 0.1 square inch) and approximately 70C/W when soldered
to a copper area of one square inch. The
J-A
values for the LLP package are also dependent on trace area, copper thickness, and the number of thermal vias used
(refer to application note AN-1187). If power disspation causes the junction temperature to exceed specified limits, the device will go into thermal shutdown.
Note 3: ESD is tested using the human body model which is a 100pF capacitor discharged through a 1.5k resistor into each pin.
Note 4: Typical numbers represent the most likely parametric norm for 25C operation.
Note 5: If used in a dual-supply system where the regulator load is returned to a negative supply, the output pin must be diode clamped to ground.
Note 6: Output voltage line regulation is defined as the change in output voltage from nominal value resulting from a change in input voltage.
Note 7: Output voltage load regulation is defined as the change in output voltage from nominal value as the load current increases from 1mA to full load.
Note 8: Dropout voltage is defined as the minimum input to output differential required to maintain the output within 100mV of nominal value.
LP38691/LP38693
www.national.com
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