MICROSEMI LX8211

LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
KEY FEATURES
DESCRIPTION
For ultra low noise operation a Bypass
pin is brought out to connect an optional
capacitor.
Significant performance
improvements over Bipolar technology
are achieved designing in CMOS:
increased regulator efficiency by
minimizing operating ground current
(typ<140uA) and it is nearly eliminated
(typ<1uA) in shutdown. The PMOS
output transistor allows for ultra low
dropout typically less than 300mV at
100mA.
! Dropout Voltage typically
175mV @ 100mA
! Ultra low shutdown Current
typically less than 1uA
! High Output accuracy trimmed
to 0.25%
! Standard pinout in SOT-23-5
! Noise Bypass feature available
! Current and Over Temperature
protection
! Stable with low cost ceramic
output capacitor
APPLICATIONS
!
!
!
!
!
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
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The LX8211 fixed/adjustable voltage
linear regulators combines low dropout,
high accuracy, ultra-low ground current
and fast response in a very small
footprint.
Using the Enable pin the regulators is
switched on with TTL logic levels,
which is especially useful for batteryoperated equipment.
Other features
include independent Thermal and Short
Circuit Current protection. The regulator
is stable with a low value ceramic output
capacitors.
Battery Operated Systems
Laptop, Notebook and PDA’s
Cellular Telephones/pagers
Hand-Held Instruments
Linear post regulators for
SMPS
PRODUCT HIGHLIGHT
CIN
1µF
VIN
ON
ENABLE
OFF
VOUT
+
¯
CBY/ADJUST
GND
COUT
1µF
470pF
Optional
TJ (°°C)
PACKAGE MARKING
LX8211
-40 to 125
-40 to 125
-40 to 125
-40 to 125
-40 to 125
-40 to 125
PACKAGE ORDER INFO
Plastic SOT-23
OUTPUT VOLTAGE
SE
5-PIN
Adjustable
LX8211-00ISE
2.5V
LX8211-25ISE
2.7V
LX8211-27ISE
2.8V
LX8211-28ISE
3.0V
LX8211-30ISE
3.3V
LX8211-33ISE
82A1
82B1
82D1
82E1
82G1
82K1
Note: Available in Tape & Reel.
Append the letter “T” to the part number. (i.e. LX8211-25ISET)
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
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.
1
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Input Voltage (VIN).........................................................................................-0.3V to +7V
Enable Input ........................................................................................... -0.3V to VIN+.3V
Output Current (IOUT) ............................................................................................. 150mA
Operating Temperature Range..................................................................... -40 to +125 °C
Maximum Junction Temperature (TJ).......................................................................150 °C
5
2
3
4
SE PACKAGE
(Top View)
THERMAL DATA
SE
5-PIN SOT-23 PACKAGE
Thermal Resistance – Junction to Ambient, θJA
#
#
220°C/W
220°C/W
Two – Layer Board
Four – Layer Board
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.
FUNCTIONAL PIN DESCRIPTION
PIN
PIN NAME
DESCRIPTION
NUMBER
VIN
1
Unregulated input supply voltage
GND
2
Ground Pin
ENABLE
3
Enable Control Input, Enable High
CBY/ADJUST
4
Reference bypass input. Adding an additional external capacitor reduces output noise . Or
adjust control input for LX8211-00.
VOUT
5
Regulated output voltage. Regulator stability is achieved with external capacitor of 1uF
APPLICATION
1
VIN
5
VOUT
ON
¯
OFF
CIN
R1
ENABLE
CBY/ADJUST
GND
2
4
R2
PACKAGE DATA
3
+
COUT
R1 

VOUT = VADJ 1 +

 R2
Figure 1 – Output Voltage Set Externally
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
Parameter
Symbol
Input Operating Voltage Range (Note 1)
Enable Input Voltage Range
Continuous Output Current Range
Input Capacitor (VIN to GND)
Output Capacitor (VOUT to GND)
Min
LX8211-xx
Typ
Units
Max
VIN
2.5
6
ENABLE
0
VIN + .3V
IOUT
CIN
COUT
1.0
1.0
V
150
.1
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RECOMMENDED OPERATING CONDITIONS
mA
1.0*
2.2*
µF
µF
Note 1: The minimum VIN has to meet two conditions VIN>2.5V and VIN>VOUT+VDROPOUT.
* Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a lower ESR and larger value capacitor will
improve the response to these load steps.
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C ≤ TA ≤ 125°C except where
otherwise noted. Test conditions: VIN = VOUT + 0.5V; IOUT =10mA; CIN = 1uF; COUT = 1uF; TJ=TA using low duty cycle pulse testing
methods.
Parameter
Symbol
LX8211-XX
Test Conditions
Min
Output Voltage (-25, -27, -28, -30, -33)
VO
TJ = 25°C
IOUT = 0mA to 150mA, VIN = VOUT + .5V to 6V
Typ
Units
Max
-1
1
%VNOM
-2.5
2.5
%VNOM
1.175
1.187
1.20
V
VADJ
TJ = 25°C
IOUT = 0mA to 150mA, VIN = 2.85V to 6V
 ∆VO

∆VIN 

VRV
VIN: VOUT + 0.5 TO 6 VOLTS, IOUT=0.1mA
0.04
0.15
%/V
 ∆VO

∆I O 

VRI
TJ = 25°C, IOUT: 0.5 TO 150mA
0.5
1.0
%VNOM
1.5
%VNOM
Adjust Reference Voltage (-00)
Line Regulation 
Load Regulation 
1.163
1.14
IOUT: 0.5 TO 150mA
ILOAD = 1mA, ∆VO = -1%
Dropout Voltage (VIN − VO )
(Note2)
VDO
0.05
V
ILOAD = 50mA, ∆VO = -1%
0.1
0.175
V
ILOAD = 100mA, ∆VO = -1%
0.175
0.3
V
ILOAD = 150mA, ∆VO = -1%
0.25
0.4
V
140
Enable = Hi
220
µA
Enable = Low
1
µA
Adjust Input Bias Current
IADJ
VADJ = 1.175V
100
nA
Enable Pin Current
IEN
VEN = VIN
100
nA
VIH
Enable Threshold
2.0
V
0.4
VIL
Short Circuit Current Limit
Power Supply Rejection Ratio
IOUTSC
PSRR
Output Noise
eN
Thermal Shutdown Temperature
TSD
VOUT = 0V
ELECTRICALS
IGND
ISTBY
Ground Pin Current
400
V
mA
TJ = 25°C, f = 120Hz
50
dB
TJ = 25°C, COUT = 10uF,CBYPASS = 470 pF
50
µV
170
°C
Note 2: Dropout voltage is defined as the input to output differential at which the output voltage drops 1% below the nominal value.
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX8211
I N T E G R A T E D
P R O D U C T S
150mA CMOS Low Dropout Regulator
P RODUCTION D ATA S HEET
BLOCK DIAGRAM
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VIN
VOUT
RA
Thermal
Shutdown
+
Current
Limit
Control
Logic
ENABLE
-
CBY/ADJUST
RB
VREF
GND
Figure 2 – Simplified Fixed Version Block Diagram (LX8211-25 / 27 / 28/ 30/ 33ISE)
VIN
VOUT
Thermal
Shutdown
+
Current
Limit
ENABLE
Control
Logic
CBY/ADJUST
-
BLOCK DIAGRAM
VREF
GND
Figure 3 – Simplified Adjustable Version Block Diagram (LX8211-00ISE)
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX8211
I N T E G R A T E D
P R O D U C T S
150mA CMOS Low Dropout Regulator
P RODUCTION D ATA S HEET
Description
Minimum Load Requirement
The LX8211 is a family of LDO (Low Drop-Out) linear regulators in a
small SOT-23 Package, which provides a compact and cost effective
solution. The family includes several fixed output voltages, along with
an adjustable version. The internal PMOS power device provides low
dropout regulation with fast line and load transient response. It also
includes internal current limit and thermal shutdown circuitry. In this
section you will find information about selection of external
capacitors, thermal and layout consideration.
The LX8211 is stable even at zero load; no minimum load is required
for operation, which is especially important in keep-alive applications.
However line regulation is improved with a minimum load of 100uA.
Input Capacitor
Short Circuit Current Protection
To improve load transient response and noise rejection a bypass
capacitor is recommended, but it is not required for stability. There are
no requirements for the ESR (Equivalent Series Resistor) on the input
capacitor, but tolerance and temperature coefficient must be
considered when selecting the capacitor to ensure the capacitor will be
around 1uF over the entire operating temperature range. For LX8211
connect ceramic type capacitor (1uF) between VIN and ground.
The LX8211 includes over current protection, when the output load
current exceeds typically 400mA the circuit forces the regulator
decrease in output.
Output Capacitor
To maintain a constant output voltage a feedback loop is necessary.
The feedback loop causes a well known a phase shift, the amount of
phase shift determines the loop stability. Therefore, LX8211 like any
low-dropout regulator, requires an output capacitor with low ESR
(Equivalent Series Resistor) connected between VOUT and GND to
stabilize the internal control loop. For the LX8211 a ceramic, tantalum
or electrolytic capacitor with the minimum recommended capacitance
value at 1.0 uF with ESR between 5mΩ and 1Ω will satisfy the
stability for whole operating range.
Bypass Capacitor (Optional) / Adjustable Output
Voltage
R1 

VOUT = VADJ 1 +

 R2
Thermal Consideration
Thermal shutdown protects the integrated circuit from thermal
overload caused from a rise in junction temperature during power
dissipation. This means of protection is intended for fault protection
only and not as a means of current or power limiting during normal
application usage. Proper thermal evaluation should be done to ensure
that the junction temperature dose not exceed it’s maximum rating.
Operating at the maximum TJ of 150°C can impact reliability . Due to
variation in individual device electrical characteristics and thermal
resistance , the built in thermal overload protection may be activated at
power levels slightly above or below the rated dissipation.
Power dissipation for regulator can be calculated using the following
equation:
PD = (VIN(MAX)-VOUT(MIN)) * IOUT(MAX)
(Note: power dissipation resulting from quiescent current is negligible)
For the SOT23 package, thermal resistance, θJA is 2200C/W when
mounted on a FR4 copper clad PCB. Junction temperature of the
integrated circuit can be calculated using:
TJ = TA + TRISE, substituting: TA + (PD * θJA).
An example: Given conditions: TA = 60°C, VIN= 4.2V, VOUT= 2.7V,
IOUT= 100mA.
Calculated values:
Total Power dissipation PD(total) = (4.2-2.7) V * 0.1A =0.15W
Junction Temperature
TJ = 60°C +(0.15W *220°C/W) = 93°C
Layout Consideration:
Enable
The Enable pin allows the LX8211 to be turned on and off. The Enable
pin is compatible with standard TTL-CMOS levels. A logic zero
(0.4V) on the Enable pin shuts the LX8211 off and reduces the supply
current to less than 1uA. Pulling the Enable input high (2.0V) causes
normal operation to resume. If the Enable feature is not used, this pin
can be connected to VIN.
Copyright  2000
Rev. 1.0b, 2002-07-02
The thermal protection shuts the LX8211 down when the junction
temperature exceeds approximately 1500C, there is no appreciable
thermal hysteresis.
The layout must be done with low impedance paths for VIN, VOUT and
Ground by applying sufficient wide traces to avoid voltage drops and
pick up noise. Adding an area of PCB copper to the GND pin (pin2)
will reduce the overall θJA since it is thermally connected to the device
substrate. This will lower the device junction temperature improving
the overall output accuracy. The input/output capacitors must be
placed as close as possible to the voltage regulator output pin. To
allow the same voltage reference for all circuits, use a star
configuration from the output capacitor to the different loads.
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
APPLICATION
The LX8211 includes the extra Bypass pin to help further reduce the
already low output noise in the regulator. If the output noise
requirement meets the specification, omit the bypass capacitor, that’s
because the capacitor impacts the start up time which is inversely
proportional to the size of bypass capacitor. The bypass capacitor
reduces the regulator phase margin, therefore it requires a larger output
capacitor to maintain stability.
The LX8211-00 adjustable regulator’s output voltage can be externally
set by connecting the ADJ pin to an external resistor divider (See
Figure 1). The output voltage can be calculated using:
Temperature Protection
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APPLICATION INFORMATION
LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
W W W. Microsemi .COM
TYPICAL CHARACTERISTICS
Typical performance characteristics, unless otherwise specified are: CIN = COUT = 1µF, CBY = 470pF, VIN = VOUT = 2.5V, TA = 25°C,
ENABLE is tied to VIN.
OUTPUT VOLTAGE vs TEMPERATURE
VADJ VOLTAGE vs TEMPERATURE
2.525
1.185
2.52
2.515
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.18
1.175
1.17
1.165
2.51
2.505
2.5
2.495
2.49
2.485
1.16
2.48
2.475
1.155
-50
-25
0
25
50
TEMPERATURE (°C)
75
100
-50
125
D R O P O UT V O LT A G E v s T E M P E R A T UR E
-25
0
25
50
TEMPERATURE (°C)
75
100
125
S H O R T C IR C UIT C UR R E N T v s T E M P E R A T UR E
v s S UP P LY V O LT A G E
350
325
-340
300
-350
275
-360
250
-370
IL =150mA
225
200
-380
175
-390
150
V IN =5V
-400
IL =100mA
125
- 410
100
75
-420
50
-430
-50
- 25
0
25
50
75
100
V IN =4V
V IN =3V
- 50
125
-25
0
25
50
75
100
125
TEMPERATURE ( °C)
TEMPERATURE (°C)
POWER SUPPLY / RIPPLE REJECTION vs FREQUENCY DROPUT
REGION
G R O UN D C UR R EN T v s S UP P LY V O LT A G E
0
-50
0dB
- 100
-40
- 150
85
50dB
CHARTS
PSSR
25
-200
115
-250
2.8
3.3
3.8
4.3
4.8
5.3
5.8
6.3
100dB
0.1
SUPPLY VOLTAGE ( V)
Copyright  2000
Rev. 1.0b, 2002-07-02
Frequency (kHz)
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
100
Page 6
LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
POWER SUPPLY RIPPLE REJECTION VS. FREQUENCY
POWER SUPPLY / RIPPLE REJECTION VS. FREQUENCY
0dB
0dB
CBYPASS = 0
PSSR
CBYPASS = 470pF
PSSR
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TYPICAL CHARACTERISTICS (CONTINUED)
50dB
100dB
50dB
100dB
Frequency (kHz)
0.1
100
0.1
ENABLE RESPONSE
VIN = 3.3V CIN = 1µF, COUT = 22µF, CBVP = 470pF, IOUT = 100mA
Frequency (kHz)
100
LOAD TRANSIENT RESPONSE
`VIN = 3.3V, CIN = 1µF, COUT = 2.2µF, STEP Load = 50mA
VIN
VOUT = 2.5V
50mV
/ DIV
1V /
DIV
50mV
/ DIV
VOUT = 2.5V
VENABLE
5V /
DIV
50mA
/ DIV
20µs / DIV
100µs / DIV
LINE REGULATION STEP RESPONSE
CIN = 1µF, COUT = 22µF, CBVP = 470pF, IOUT = 100mA
10mV
/ DIV
ISTEP = 50mA
LOAD TRANSIENT RESPONSE
VIN = 3.3V, CIN = 1µF, COUT = 2.2µF, STEP Load = 100mA
50mV
/ DIV
VOUT = 2.5V
VOUT = 2.5V
CHARTS
VIN
3.75V
100m
A/
DIV
2.75V
ISTEP = 100mA
20µs / DIV
20µs / DIV
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX8211
I N T E G R A T E D
150mA CMOS Low Dropout Regulator
P R O D U C T S
P RODUCTION D ATA S HEET
SE
W W W. Microsemi .COM
PACKAGE DIMENSION
5 Pin Plastic SOT-23
Dim
D
G
H
E
A1
A
C
B
F
J
I
A
A1
B
C
D
E
F
G
H
I
J
K
MILLIMETERS
MIN
MAX
0.90
1.30
0.90
1.45
0.25
0.50
0.09
0.20
2.80
3.10
1.50
1.75
0.95 BSC
1.90 BSC
2.60
3.00
0.35
0.55
0.00
0.15
10° MAX
INCHES
MIN
MAX
0.035
0.051
0.035
0.057
0.010
0.020
0.004
0.008
0.110
0.122
0.059
0.069
0.038 BSC
0.075 BSC
0.102
0.118
0.014
0.022
0.000
0.006
10° MAX
K
Note:
1. 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.
MECHANICALS
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
LX8211
I N T E G R A T E D
P R O D U C T S
150mA CMOS Low Dropout Regulator
P RODUCTION D ATA S HEET
W W W. Microsemi .COM
NOTES
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to
Microsemi and is current as of publication date. This document may not be modified in
any way without the express written consent of Microsemi. Product processing does not
necessarily include testing of all parameters. Microsemi reserves the right to change the
configuration and performance of the product and to discontinue product at any time.
Copyright  2000
Rev. 1.0b, 2002-07-02
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9