A
M I C R O S E M I
C O M P A N Y
LX8630-xx
3A BiCMOS Very Low Dropout Regulators
P
RODUCTION
D
ATA
S
HEET
The LX8630 family are positive very
They are
low dropout regulators.
designed to provide a power supply for
very low headroom applications, such as
3.3V – 2.5V.
BiCMOS technology
allows an
effective series pass element resistance,
R
DS(ON)
of 150m
dropout voltage of 450mV at 3A.
Low Quiescent Current and Logic-
Controlled Shutdown
help conserve
battery life and increase system efficiency.
Typical quiescent current is under 400
A
irrespective of load current, while the
Shut
device will enter shutdown mode when the
SHDN pin is pulled low.
Thermal and Short-Circuit Current
Limiting:
the LX8630 limits the current
when the output is shorted, protecting the
sensitive load circuits. The device will
also turn off if the junction temperature
exceeds 150°
Available in Popular TO-220 and
TO-263 Power Packages:
adjustable
versions have five leads, and fixed output
voltage devices are supplied in three lead
packages.
Dropout Voltage Typically
W W W .
Microsemi
.
COM
450mV at 3A and 50mV at
10mA
Low Quiescent Current,
Typically Under 400µA,
irrespective of Load
Shutdown Current 10µA
Adjustable Output Version in
5-Pin TO-220 & TO-263
Packages
Low Reverse Leakage
Current
Short-Circuit and Thermal
Shutdown Protection
IMPORTANT:
For the most current data, consult
MICROSEMI’s
website:
http://www.microsemi.com
3.3V & 2.5V Supplies for
Memory, Microprocessors,
Clock Circuits, Etc.
Portable Equipment
LX8 630-xx S im plified B lock D iagra m
V
IN
C urrent
Lim it
R eference
C urrent
C harge
P um p
R
A
V
O UT
A D J*
1.25V
+
R
B
SHDN*
V
IN
/2
-
GND
R
A
R
B
-
25K
25K
R everse
V oltage
S ense
LX 8630-00
-
25K
41K
T herm al
S hutdown
* Adjustable 5 lead ve rsion only
LX 8630-25
LX 8630-33
LX8630-
XX
LX8630-
XX
Output
Voltage
3.3
0 to 125
2.5
ADJ(00)
T
A
(°C)
Plastic TO-220
P
3-Pin
LX8630-33CP
LX8630-25CP
-
Plastic TO-220
P
5-Pin
-
-
LX8630-00CP
Plastic TO-263
DD
3-Pin
LX8630-33CDD
LX8630-25CDD
-
Plastic TO-263
DD
5-Pin
-
-
LX8630-00CDD
Note: Available in Tape & Reel.
Append the letter “T” to the part number. (i.e. LX8630-33CDDT)
Copyright
©
2000
Rev. 1.0a,2000-11-28
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
A
M I C R O S E M I
C O M P A N Y
LX8630-xx
3A BiCMOS Very Low Dropout Regulators
P
RODUCTION
D
ATA
S
HEET
Input Voltage (V
IN
) ......................................................................................................6.5V
SHDN Pin..............................................................................................-0.3V to V
IN
+0.3V
Operating Junction Temperature
Plastic (P & DD Packages)................................................................................... 150°C
Storage Temperature Range ........................................................................-65°C to 150°C
Lead Temperature (Soldering, 10 seconds) ............................................................... 300°C
Note:
Exceeding these ratings could cause damage to the device. All voltages are with respect to
Ground. Currents are positive into, negative out of specified terminal.
TAB is GND
V
OUT
GND
V
IN
W W W .
Microsemi
.
COM
3
2
1
DD P
ACKAGE
(3-
PIN
)
(Top View)
P
LASTIC
TO-220 3-P
IN
THERMAL RESISTANCE
-
JUNCTION TO
T
AB
,
θ
JT
THERMAL RESISTANCE
-
JUNCTION TO AMBIENT
,
θ
JA
P
LASTIC
TO-220 5-P
IN
THERMAL RESISTANCE
-
JUNCTION TO
T
AB
,
θ
JT
THERMAL RESISTANCE
-
JUNCTION TO AMBIENT
,
θ
JA
P
LASTIC
TO-263 3-P
IN
THERMAL RESISTANCE
-
JUNCTION TO
T
AB
,
θ
JT
THERMAL RESISTANCE
-
JUNCTION TO AMBIENT
,
θ
JA
P
LASTIC
TO-263 5-P
IN
THERMAL RESISTANCE
-
JUNCTION TO
T
AB
,
θ
JT
THERMAL RESISTANCE
-
JUNCTION TO AMBIENT
,
θ
JA
T AB is G N D
V
OUT
ADJ
GND
SHDN
V
IN
5
P
4
3
2.1°C/W
60°C/W
2
1
D D P
A C K A G E
(5-P
IN
)
P
(T op V iew)
2.1°C/W
60°C/W
T A B is G N D
DD
5
4
V
OUT
AD J
GND
SH D N
V
IN
2.1°C/W
60°C/W
3
2
1
P P
A C K A G E
(5-P
IN
)
(Top View)
DD
2.1°C/W
60°C/W
TAB is GND
3
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
The
θ
JA
numbers are guidelines for the thermal performance of the device/pc-board system.
All of the above assume no ambient airflow.
•
θ
JA
can be improved with package soldered to 0.5IN
2
copper area over backside
ground plane or internal power plane
.
θ
JA
can vary from 20°C/W to > 40°C/W
depending on mounting technique. See table below for thermal resistance
guidelines
:
V
OUT
GND
V
IN
2
1
P P
ACKAGE
(3-P
IN
)
(Top View)
Copper Area
(Topside)*
2.5 sq” (1613mm
2
)
1.0 sq” (645 mm
2
)
0.17 sq” (110 mm
2
)
Copper Area
(Backside)*
2.5 sq” (1613mm
2
)
2.5 sq” (1613mm
2
)
2.5 sq” (1613mm
2
)
Board Area
2.5 sq” (1613mm
2
)
2.5 sq” (1613mm
2
)
2.5 sq” (1613mm
2
)
Thermal
Resistance
(θ
JA
)
25°C/W
27°C/W
35°C/W
P
ACKAGE
D
ATA
P
ACKAGE
D
ATA
*Tab of device attached to topside copper
Copyright
©
2000
Rev. 1.0a,2000-11-28
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
A
M I C R O S E M I
C O M P A N Y
LX8630-xx
3A BiCMOS Very Low Dropout Regulators
P
RODUCTION
D
ATA
S
HEET
W W W .
Microsemi
.
COM
V
IN
V
OUT
GND
ADJ
SHDN
Positive supply input for the regulator. Bypass to GND with at
source is further than 1 inch from the device.
regulation, rather it is needed for transient response. Size your output capacitor to meet the transient loading
requirement. If you have a very dynamic load, a larger capacitor will improve the response to these load steps.
Reference ground. The input and output bypass capacitors should be connected to this pin. The tab on the TO-
220 and TO-263 packages along with the ground pin are also used for heatsinking the device.
Feedback pin for the regulator. For the LX8630-00, the output voltage can be set by two external resistors with
the following relationship: V
OUT
= 1.25V * (1+R
A
/R
B
) where R
A
is the resistor connected between V
OUT
and ADJ,
R
B
is the resistor connected between ADJ and GND pin.
Shutdown pin. For the LX8630-00, this pin has a threshold of about V
IN
/2, it should be actively pulled high to
enable the regulator. This can be accomplished with a resistive pull-up. When low, it turns off the regulator and
puts the device in a low current shutdown state.
V
IN
1
IN
OUT
5
V
OUT
R
A
C
IN
LX 8630-00
SHDN
2
GND
3
ADJ
4
C
OUT
V
REF
R
B
V
OUT
=
V
REF
1
+
R
A
R
B
P
IN
D
ESCRIPTION
P
IN
D
ESCRIPTION
FIGURE 1
–
Typical Application
Copyright
©
2000
Rev. 1.0a,2000-11-28
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
A
M I C R O S E M I
C O M P A N Y
LX8630-xx
3A BiCMOS Very Low Dropout Regulators
P
RODUCTION
D
ATA
S
HEET
W W W .
Microsemi
.
COM
PARAMETER
INPUT VOLTAGE
LOAD CURRENT (WITH ADEQUATE HEATSINKING)
INPUT CAPACITOR (V
IN
TO GND)
OUTPUT CAPACITOR (V
OUT
TO GND)
SYMBOL
V
IN
MIN.
3.0
0.01
10
22
TYP.
MAX.
5.5
3
UNITS
V
A
100
220*
* Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a larger capacitor will improve
the response to these load steps (see charts 2&3)
(Unless otherwise specified, the following specifications apply over the operating ambient temperatures for the LX8630-xxC with 0°C
≤
T
A
≤
125°C; V
IN
= V
OUT
+ 1.5V; I
OUT
= 10mA; C
IN
= 10
' (
OUT
)
' *
J
= T
A
. Test conditions: Low duty cycle pulse testing
techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
Parameter
Symbol
Test Conditions
LX8630-xx
Min
Typ
Max
Units
LX8630-33 FIXED 3.3V, 3A
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage (V
DO
= V
IN
- V
OUT
)
V
OUT
V
REG
I
REG
V
DO
T
J
= 25°C
Over Temperature
V
IN
= 3.9V to 5.5V
I
OUT
= 10mA to 3 A
I
OUT
= 3A,
OUT
= -1%
I
OUT
= 1.5A,
OUT
= -1%
I
OUT
= 10mA,
OUT
= -1%
Short Circuit Current
Quiescent Current
Reverse Leakage Current
I
SC
I
Q
I
REV
V
OUT
= 0V
I
OUT
= 10mA to 3A
0V < V
IN
< V
OUT
, V
OUT
< 3.4V (at V
OUT
)
0V < V
IN
< V
OUT
, V
OUT
< 3.4V (at V
IN
)
-50
3.25
3.22
2
18
0.4
0.3
0.05
5
400
50
0
3.3
3.35
3.38
8
40
0.6
0.4
0.15
6.5
600
650
A
V
V
mV
mV
mA
LX8630-25 FIXED 2.5V, 3A
Output Voltage
Line Regulation
Load Regulation
V
OUT
V
REG
I
REG
T
J
= 25°C
Over Temperature
V
IN
= 3.1V to 5.5V
I
OUT
= 10mA to 3 A
I
OUT
= 3A,
OUT
= -1%, T
J
= 85°C
Dropout Voltage (V
DO
= V
IN
- V
OUT
)
V
DO
I
OUT
= 1.5A,
OUT
= -1%
I
OUT
= 10mA,
OUT
= -1%
Short Circuit Current
Quiescent Current
Reverse Leakage Current
I
SC
I
Q
I
REV
V
OUT
= 0V
I
OUT
= 10mA to 3A
0V < V
IN
< V
OUT
, V
OUT
< 2.6V (at V
OUT
)
0V < V
IN
< V
OUT
, V
OUT
< 2.6V (at V
IN
)
-50
2.46
2.44
2.5
2.5
2
14
0.4
0.3
0.05
5
400
50
0
2.54
2.56
6
30
0.6
0.45
0.15
6.5
600
650
A
V
mV
mV
V
E
LECTRICALS
E
LECTRICALS
mA
Copyright
©
2000
Rev. 1.0a,2000-11-28
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
A
M I C R O S E M I
C O M P A N Y
LX8630-xx
3A BiCMOS Very Low Dropout Regulators
P
RODUCTION
D
ATA
S
HEET
Parameter
Symbol
Test Conditions
LX8630-xx
Min
Typ Max
Units
W W W .
Microsemi
.
COM
LX8630-00 ADJUSTABLE OUTPUT, 3A
Reference Voltage
Line Regulation
Load Regulation
V
REF
V
REG
I
REG
T
J
= 25°C
Over Temperature
V
IN
= (V
O
+ 0.6V) to 5.5V @ ADJ Pin (Note 1)
I
OUT
= 10mA to 3A @ ADJ Pin
I
OUT
= 3A,
OUT
= -1%, T
J
= 85°C
Dropout Voltage
V
DO
I
OUT
= 1.5A,
OUT
= -1%
I
OUT
= 10mA,
OUT
= -1%
Short Circuit Current
Quiescent Current
I
Q
Quiescent Current in Shutdown
Reverse Leakage Current
Bias Current at ADJ Pin
Shutdown Threshold
SHDN Bias Current
Note 1: V
IN
min.
I
REV
I
BIAS
V
SHDN
I
SHDN
V
SHDN
falling
V
SHDN
rising
V
SHDN
< 0.8V
V
SHDN
= 3V
0.8
V
IN
= 4.8V; V
SHDN
<0.8V
0V < V
IN
< V
OUT
, V
OUT
< 5.5V (at V
OUT
)
0V < V
IN
< V
OUT
, V
OUT
< 5.5V (at V
IN
)
-50
1
50
0
100
(V
IN
/2)
(V
IN
/2)
-2
-1
V
40
650
I
SC
V
OUT
= 0V
I
OUT
= 10mA to 3A
1.23
1.22
1.25
1.25
2
7
0.4
0.3
0.05
5
400
1.27
1.28
4
15
0.6
0.45
0.15
6.5
600
A
V
V
mV
mV
mA
nA
300
250
V-Dropout (mV)
200
+125
150
+25
-25
E
LECTRICALS
E
LECTRICALS
100
50
0
0.1
0.5
1.0
1.5
2.0
2.5
3.0
Current Load (Amps)
CHART 1
– Dropout Voltage vs. Output Current (Typical – LX8630-33CCD)
Copyright
©
2000
Rev. 1.0a,2000-11-28
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
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