ETC LX8610

A
LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
KEY FEATURES
DESCRIPTION
W W W. Microsemi .COM
The LX8610 family are positive
very low dropout regulators. They are
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, RDS(ON) of 250mΩ resulting in a
typical dropout voltage of 250mV at
1A.
Low Quiescent Current and LogicControlled Shutdown help conserve
battery life and increase system
efficiency. Typical quiescent current
is under 400µA irrespective of
! Dropout Voltage Typically
250mA At 1A And 50mV At
10mA
! Low Quiescent Current, Under
400µA, Irrespective Of Load
! Shutdown Current 10µA
! Adjustable Output Version In 8pin SOIC Package
! Fixed Outputs Of 2.5V, 3.3V
Available In 3-Pin SOT-223
Package
! Low Reverse Leakage Current
! Short-Circuit And Thermal
Shutdown Protection
load current, while the shutdown current
is only 10µA. The device will enter
shutdown mode when the SHDN pin is
pulled low.
Thermal & Short-Circuit Current
Limiting: the LX8610 limits the current
when the output is shorted, so protecting
sensitive load circuits. The device will
also turn off if the junction temperature
exceeds 155°C.
Available in small outline SOT-223
and 8-pin SOIC: Adjustable versions
use the 8-pin SOIC and fixed output
voltage devices are supplied in the 3lead SOT-223.
APPLICATIONS/BENEFITS
APPLICATIONS/BENEFITS
! 3.3V & 2.5V Supplies For
Memory, Microprocessors,
Clock Circuits, Etc.
! Portable Equipment
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
LX8610-xx Sim plified Block Diagram
V OUT
V IN
Reference
Current
Current
Lim it
RA
Charge
Pum p
ADJ*
1.25V
+
RB
-
SHDN*
GND
V IN /2
RA
Reverse
Voltage
Sense
Therm al
Shutdown
RB
LX8610-00
-
-
LX8610-25
25K
25K
LX8610-33
41K
25K
LX8610-XX
* Adjustable version in 8 lead package only.
TJ (°°C)
0 to 125°C
PACKAGE ORDER INFO
PLASTIC SOT-223
OUTPUT
ST 3-PIN
VOLTAGE
3.3
LX8610-33CST
2.5
LX8610-25CST
ADJ (00)
–
DM
Plastic Power SOIC
8-PIN
LX8610-33CDM
LX8610-25CDM
LX8610-00CDM
Note: Available in Tape & Reel.
Append the letter “T” to the part number. (i.e. LX8610CDMT)
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
A
LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
TAB IS GN D
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.
THERMAL DATA
ST
V OU T
2
GN D/HS
1
V IN
ST PACKAGE
(Top View)
V OUT
1
8
ADJ
GND/HS
2
7
GND/HS
GND/HS
3
6
G ND/HS
SHDN
4
5
V IN
Plastic SOT-223 Package 3-Pin
DM PACKAGE
(Top View)
THERMAL RESISTANCE-JUNCTION TO TAB,
θJT
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
DM
3
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Input Voltage (VIN).......................................................................................................6.5V
SHDN Pin..............................................................................................-0.3V to VIN+0.3V
Output Current ................................................................................................................1A
Operating Junction Temperature Plastic (ST & DM) Packages................................. 125°C
Storage Temperature....................................................................................-65°C to 150°C
Lead Temperature (Soldering, 10 Seconds)............................................................... 300°C
θJA
15°C/W
150° C/W
HEAT SINK APPROACH
Plastic SOIC Package 8-Pin
THERMAL RESISTANCE-JUNCTION TO TAB,
θJT
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θJA
30° C/W
90° C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
θJA can be improved with package soldered copper area over backside ground plane or
internal power plane. θJA can vary from 45°C/W > 75°C/W depending on mounting
technique. See table below for thermal resistance guidelines:
Copper Area
(Backside)*
2.0 sq” (1290mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.25 sq” (161 mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.1 sq” (65 mm2)
0.1 sq” (65 mm2)
2.0 sq” (1290mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.25 sq” (161 mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.1 sq” (65 mm2)
0.1 sq” (65 mm2)
Board Area
ST (SOT-223)
2.0 sq” (1290mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.25 sq” (161 mm2)
Thermal
Resistance
(θ
θJA)
45°C/W
50°C/W
60°C/W
70°C/W
1
8
2
7
3
6
4
5
PACKAGE DATA
Copper Area
(Topside)*
Possible Heat Sink Approaches
using PCB Copper
DM (SOIC)
2.0 sq” (1290mm2)
1.0 sq” (645 mm2)
0.5 sq” (323 mm2)
0.25 sq” (161 mm2)
60°C/W
67°C/W
70°C/W
75°C/W
*Tab of device attached to topside copper, or leads 2,3,5,6 of SOIC package
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
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LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
FUNCTIONAL PIN DESCRIPTION
DESCRIPTION
VIN
Positive supply input for the regulator. Bypass to GND with at least 2.2µF of low ESR, ESL capacitance if
supply source is further than 1 inch from the device.
VOUT
Output for the regulator. It is recommended to bypass to GND with at least 10µF although this is not required
for 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.
GND/HS
Reference ground. The input and output bypass capacitors should be connected to this pin. In addition the tab
on the SOT-223 package and pins 2,3,6, and 7 on the SOIC package are also used for heat sinking the device.
ADJ
Feedback pin for the regulator. For the LX8610-00, the output voltage can be set by two external resistors with
the following relationship: VOUT = 1.25V * (1 + RA / RB) where RA is the resistor connected between VOUT and
ADJ, and RB is the resistor connected between ADJ and GND.
SHDN
Shutdown input. This pin has a threshold of about VIN / 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.
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PIN NAME
TYPICAL APPLICATION
VIN
5
IN
OUT
LX8610-00
CIN
SHDN
4
GND
2,3
6,7
VOUT
1
RA
ADJ
8
VREF
COUT
RB

RA 

RB 
VOUT = VREF 1 +

PACKAGE DATA
Figure 1 – Typical Application
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
A
LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
RECOMMENDED OPERATING CONDITIONS
Symbol
Min
LX8610
Typ
Units
Max
Input Voltage
VIN
3.1
5.5
V
Load Current (with adequate heatsinking)
10
1000
mA
Input Capacitor (VIN to GND)
2.2
10
µF
Output Capacitor (VOUT to GND)
10
22*
µF
* 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.
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 125°C except where
otherwise noted. Test conditions: VIN = VOUT + 1.5V; IOUT = 10mA; CIN = 10µF; COUT = 22µF; TJ = TA.
Parameter
!
Test Conditions
Min
LX8610-xx
Typ
Max
Units
LX8610-33 FIXED 3.3V, 1A
Output Voltage
VOUT
Line Regulation
Load Regulation
VREG
IREG
Dropout Voltage (VDO = VIN–VOUT)
VDO
Short Circuit Current
ISC
Quiescent Current
IQ
Reverse Leakage Current
!
Symbol
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Parameter
IREV
Shutdown Threshold *
VSHDN
SHDN Bias Current *
ISHDN
TJ = 25°C
VIN = 3.8 to 5.5V, IOUT = 10mA to 1A
VIN = 3.45V to 5.5V
IOUT = 10mA to 1A
IOUT = 1A, VOUT = ∆VOUT –1%
IOUT = 0.5A, VOUT = ∆VOUT – 1%
IOUT = 10mA, VOUT = ∆VOUT – 1%
VOUT = 0V
IOUT = 10mA to 1A
VIN = 4.8V; VSHDN < 0.8V
0V < VIN < VOUT, VOUT <3.4V (at VOUT)
0V < VIN < VOUT, VOUT <3.4V (at VIN)
VSHDN falling
3.25
3.22
-50
0.8
VSHDN rising
VSHDN < 0.8V
VSHDN = 3V
3.3
4
5
0.25
0.15
0.05
1.25
400
1
400
0
(VIN / 2)
(VIN / 2)
-2
-1
3.35
3.38
8
10
0.45
0.25
0.15
1.7
600
40
650
V
mV
mV
V
A
µA
µA
mA
V
µA
LX8610-25 FIXED 2.5V, 1A
VOUT
Line Regulation
Load Regulation
VREG
IREG
Dropout Voltage (VDO = VIN–VOUT)
VDO
Short Circuit Current
ISC
Quiescent Current
IQ
Reverse Leakage Current
IREV
Shutdown Threshold *
VSHDN
SHDN Bias Current *
ISHDN
Copyright  2000
Rev. 1.0c, 2001-11-16
TJ = 25°C
VIN = 3.1V, IOUT = 10mA to 1A
VIN = 3.1V to 5.5V, IOUT = 10mA
IOUT = 10mA to 1A
IOUT = 1A, VOUT = ∆VOUT –1%
IOUT = 0.5A, VOUT = ∆VOUT – 1%
IOUT = 10mA, VOUT = ∆VOUT – 1%
VOUT = 0V
IOUT = 10mA to 1A
VIN = 4.8V; VSHDN < 0.8V
0V < VIN < VOUT, VOUT < 2.6V (at VOUT)
0V < VIN < VOUT, VOUT <2.6V (at VIN)
VSHDN falling
2.46
2.44
-50
0.8
2.5
2.5
4
5
0.25
0.15
0.05
1.25
300
1
400
0
VIN / 2
VSHDN rising
(VIN / 2)
VSHDN < 0.8V
-2
VSHDN = 3V
-1
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
2.54
2.56
8
10
0.45
0.25
0.15
1.7
600
40
650
V
mV
mV
V
A
µA
µA
mA
V
µA
Page 4
ELECTRICALS
Output Voltage
A
LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
ELECTRICAL CHARACTERISTICS (CONTINUED)
!
Symbol
Test Conditions
Min
LX8610-xx
Typ
Max
Units
LX8610-00 ADJUSTABLE OUTPUT, 1A
Reference Voltage
VREF
Line Regulation
Load Regulation
Short Circuit Current
VREG
IREG
ISC
Dropout Voltage (VDO = VIN–VOUT)
VDO
Quiescent Current
IQ
Quiescent Current in Shutdown
Reverse Leakage Current
IREV
Bias Current at ADJ Pin
IBIAS
Shutdown Threshold *
V SHDN
SHDN Bias Current *
I SHDN
1.23
1.22
TJ = 25°C
VIN = 3.1V, IOUT = 10mA to 1A
VIN = 3.1V to 5.5V, IOUT = 10mA
IOUT = 10mA to 1A
VOUT = 0V
IOUT = 1A, VIN > 4V
IOUT = 0.5A, VIN > 3V
IOUT = 10mA, VIN > 3V
IOUT = 10mA to 1A, VIN = 5.5V
VIN = 4.8V; VSHDN < 0.8V
0V < VIN < VOUT, VOUT < 5.5V (at VOUT)
1.22
1.25
4
7
1.25
0.25
0.15
0.05
400
1.27
1.28
8
15
1.7
0.45
0.25
0.15
600
1
40
400
650
V
mV
mV
A
V
µA
µA
0V < VIN < VOUT, VOUT <5.5V (at VIN)
-50
0
mA
100
nA
V SHDN falling
0.8
(VIN / 2)
V SHDN rising
(VIN / 2)
V SHDN < 0.8V
-2
V SHDN = 3V
-1
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Parameter
V
µA
* Note: Shutdown Threshold and Shutdown Bias Current apply only to 8-Pin SOIC package outline versions
DROPOUT VOLTAGE VS. OUTPUT CURRENT
L X 861 0 D ropout vs. L oad vs. T em p
350
300
250
200
0
25
75
100
125
150
ELECTRICALS
100
50
0
0
0 .2 5
0 .5
0 .7 5
1
FIGURE 2 – Dropout Voltage Vs. Output Current (Typical – LX8610-25CST)
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
A
LINFINITY
M I C R O S E M I
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
C O M P A N Y
P RODUCTION D ATASHEET
ST
W W W. Microsemi .COM
MECHANICAL DIMINSIONS
3-Pin Plastic SOT-223
D
Dim
B1
E
H
2
1
3
B
F
G
L
K
A
J
DM
I
C
A
B
B1
C
D
E
F
G
H
I
J
K
L
MILLIMETERS
MIN
MAX
1.55
1.80
0.65
0.85
2.95
3.15
0.25
0.35
6.30
6.70
3.30
3.70
2.30 BSC
4.60 BSC
6.71
7.29
–
0.91
0.02
0.10
10° MAX
.084
1.04
INCHES
MIN
MAX
0.061
0.071
0.026
0.033
0.116
0.124
0.010
0.014
0.248
0.264
0.130
0.146
0.0905 BSC
0.181 BSC
0.264
0.287
–
0.036
.0008
.004
10° MAX
0.033
0.041
MILLIMETERS
MIN
MAX
4.83
5.00
3.81
3.94
1.35
1.75
0.33
0.51
–
0.77
1.27 BSC
0.19
0.25
0.13
0.25
4.80
5.21
–
8°
5.79
6.20
–
0.10
INCHES
MIN
MAX
0.190
0.197
0.150
0.155
0.053
0.069
0.013
0.020
–
0.030
0.050 BSC
0.007
0.010
0.005
0.010
0.189
0.205
–
8°
0.228
0.244
–
0.004
8-Pin Plastic SOIC
A
Dim
P
B
G
L
D
K
J
F
*Lead Coplanarity
Note: Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006”) on any side. Lead dimension shall
not include solder coverage.
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
MECHANICALS
M
C
A
B
C
D
F
G
J
K
L
M
P
*LC
A
LINFINITY
M I C R O S E M I
C O M P A N Y
LX8610-xx
1A BiCMOS Very Low Dropout Regulators
P RODUCTION D ATASHEET
W W W. Microsemi .COM
NOTES
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to
LinFinity and is current as of publication date. This document may not be modified in any
way without the express written consent of LinFinity. Product processing does not
necessarily include testing of all parameters. LinFinity reserves the right to change the
configuration and performance of the product and to discontinue product at any time.
Copyright  2000
Rev. 1.0c, 2001-11-16
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7