LX8221
TM
®
Dual 150mA CMOS Low Dropout Regulator
P
RODUCTION
D
ATA
S
HEET
DESCRIPTION
KEY FEATURES
Compact Regulators With
Two 150mA Outputs
Dropout Voltage Typically
175mV @ 100mA
Ultra Low Shutdown
Current Typically Less
Than 1µA
Output Trimmed to 0.5%
Small MSOP-10 Package
Over Current &
Temperature Protection
Stable with Ceramic or
Tantalum Capacitors
APPLICATIONS
Battery Operated Systems
Laptop, Notebook and PDA’s
Cellular Telephones/Pagers
Instrumentation
Linear Post Regulators for
SMPS
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OM
The LX8221 family of dual output
linear regulators provide for the
selection of either fixed or adjustable
output voltages, and combine low
dropout operation, fast transient
performance, tight output voltage
accuracy, and ultra-low ground current
within a very small package footprint.
The PMOS output transistor allows
for an ultra-low dropout characteristic
(e.g., typically less than 175mV at
100mA). The individual regulators can
be powered from either separate supply
voltages or the same supply voltage
between 2.8V to 6V allowing for
maximum system flexibility.
An optional ceramic or tantalum type
capacitor may be connected to each
Bypass pin separately to improve
performance in critical low-noise
applications.
Overall regulator efficiency has been
improved with a minimized operating
ground current (typical < 140µA per
regulator). Further, this ground current
is virtually eliminated in shutdown mode
(typical < 1µA).
Other safety features include channel
independent Thermal and Short Circuit
Current protection.
Separate Enable pins allow each
regulator to be switched on and off
independently by applying a TTL logic
level control signal to the Enable pin
further enhancing system level power
management.
These features combined with a small
footprint (i.e., 10-pin MSOP package)
make the LX8221 especially useful for
battery-operated equipment such as
cellular telephones, laptop computers
and PDA equipment.
IMPORTANT:
For the most current data, consult
Microsemi’s
website:
http://www.microsemi.com
PRODUCT HIGHLIGHT
5.0V
VIN2
VIN1
3.3V
CB1
ADJ
GND
VOUT1
VOUT2
R1
N/C
EN1
EN2
}
To Control Logic
On
Off
5.0V
VIN2
VIN1
3.3V
CB1
ADJ
N/C
EN1
EN2
VOUT1
VOUT2
GND
}
To Control Logic
On
Off
R1
R2
R2
R1
R2
Fixed / Adjustable Application
Adjustable / Adjustable Application
PACKAGE ORDER INFO
LX8221
LX8221
T
A
(°C)
-40 to 85
-40 to 85
-40 to 85
-40 to 85
VOUT1
Adjustable
2.5V
2.7V
3.0V
VOUT2
Adjustable
Adjustable
Adjustable
Adjustable
Plastic MSOP 10-Pin
DU
RoHS Compliant / Pb-free
Transition D/C: 0432
Package Marking
8221 AIDU LX
8221 BIDU LX
8221 DIDU LX
8221 GIDU LX
LX8221AIDU
LX8221BIDU
LX8221DIDU
LX8221GIDU
Contact Microsemi for additional / available options
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8221AIDU-TR)
Copyright
©
2000
Rev. 1.1a, 2006-01-19
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX8221
TM
®
Dual 150mA CMOS Low Dropout Regulator
P
RODUCTION
D
ATA
S
HEET
ABSOLUTE MAXIMUM RATINGS
Input Voltage (VIN1, VIN2) .......................................................................... -0.3V to +7V
Output Current (I
OUT1
, I
OUT2
)................................................................................. 150mA
Operating Temperature Range .....................................................................-40 to +125
°C
Maximum Junction Temperature (T
J
) ...................................................................... 150
°C
Storage Temperature (T
J
) .............................................................................-65 to +150
°C
Peak Package Solder Reflow Temp. (40 second max. exposure)................. 260°C (+0, -5)
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.
PACKAGE PIN OUT
VOUT1
CB1
NC
EN2
VIN2
1
2
3
4
5
10
9
8
7
6
VIN1
EN1
GND
ADJ
VOUT2
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DU P
ACKAGE
(Top View)
“NC” = No Internal Connection
RoHS / Pb-free 100% Matte Tin Lead Finish
THERMAL DATA
FRONT MARKING
DU
Plastic MSOP 8-Pin
THERMAL RESISTANCE
-
JUNCTION TO
A
MBIENT
,
θ
JA
206°C/W
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JC
).
The
θ
JA
numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
8221
xIDU
LX
x = Voltage Combination
i.e. A = Adj/Adj
FUNCTIONAL PIN DESCRIPTION
P
IN
N
AME
VIN1/VIN2
GND
EN1/EN2
CB1
VOUT1/VOUT2
ADJ (1, 2)
Unregulated input supply voltage
Ground Pin
Enable control input: Logic high = Enable; logic low or open = Shutdown
Reference bypass input. Adding an additional external capacitor reduces output noise.
Regulated output voltage. Regulator stability is achieved with external capacitor of 1µF
Adjust pin. Connect a resistor divider to this pin to establish preferred output voltage.
BLOCK DIAGRAM
VIN1
EN1
EN2
VIN2
D
ESCRIPTION
VOUT1
THERMAL
SENSOR
THERMAL
SENSOR
VOUT2
P
ACKAGE
D
ATA
P
ACKAGE
D
ATA
CURRENT
LIMIT
CURRENT
LIMIT
+
CB1
-
VREF
CONTROL
LOGIC
CONTROL
LOGIC
+
-
VREF
ADJ
GND
Copyright
©
2000
Rev. 1.1a, 2006-01-19
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
LX8221
TM
®
Dual 150mA CMOS Low Dropout Regulator
P
RODUCTION
D
ATA
S
HEET
RECOMMENDED OPERATING CONDITIONS
Parameter
Input Operating Voltage Range (Note 1)
Enable Input Voltage Range
Continuous Output Current Range
Input Capacitor (V
IN
to GND)
Output Capacitor (V
OUT
to GND)
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Symbol
VIN1, VIN2
EN1/2
I
OUT
1,
I
OUT
1
C
IN
C
OUT
Min
2.5
LX8221
Typ
Max
6
V
IN
+ 0.3V
Units
V
V
mA
µF
µF
150
1.0*
1.0*
2.2
Note 1: The minimum V
IN
has to meet two conditions V
IN
> 2.5V and V
IN
> V
OUT
+ V
DROPOUT
, at high line voltage conditions output current may be limited to less than
150mA due to the power dissipation.
* 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.
Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C
≤
T
A
≤
85°C except
where otherwise noted. Test conditions:
V
IN
= V
OUT
+ 0.5V; I
OUT
=10mA; C
IN
= 1
µ
F; C
OUT
= 1
µ
F; T
J
= T
A
using low duty cycle pulse
testing methods.
LX8221
Parameter
Symbol
Test Conditions
Units
Min
Typ
Max
Output Voltage (2.5, 2.7, 3.0, ADJ)
Adjust Reference Voltage
Line Regulation
VOUT1/2
V
ADJ
V
RV
V
RI
T
J
= 25°C
0mA
≤
I
OUT1/2
≤
100mA, (V
OUT1/2
+ 0.5V)
≤
V
IN
≤
6V
T
J
= 25°C
0mA
≤
I
OUT1/2
≤
100mA, 2.85V
≤
V
IN
≤
6V
(V
OUT1/2
+ 0.5V)
≤
V
IN
≤
5V, I
OUT1/2
= 0.1mA
T
J
= 25°C, 0.5mA
≤
I
OUT1/2
≤
150mA
0.5mA
≤
I
OUT1/2
≤
100mA
I
LOAD1/2
= 1mA,
Δ
VO
= -1%
I
LOAD1/2
= 50mA,
Δ
VO
= -1%
I
LOAD1/2
= 100mA,
Δ
VO
= -1%
I
LOAD1/2
= 150mA,
Δ
VO
= -1%
EN1 = High, EN2 = High
EN1 = Low, EN2 = Low
V
ADJ
= 1.25V
V
EN1/2
= V
IN
2.0
0.4
VOUT1 = 0V, VOUT2 = 0V
T
J
= 25°C, f = 120Hz
T
J
= 25°C, C
OUT
= 10µF,C
BYPASS
= 470pF
400
50
50
170
-1
-2.5
1.163
1.140
1
2.5
1.187
1.210
0.15
%
V
%/V
%V
NOM
ELECTRICAL CHARACTERISTICS
1.175
0.04
0.5
⎛ Δ
V
O
⎞
⎜
Δ
V
IN
⎟
⎝
⎠
⎛ Δ
V
O
⎞
Load Regulation
⎜
Δ
I
O
⎟
⎝
⎠
1.5
0.050
0.175
0.3
0.4
440
1
100
100
Dropout Voltage
(Note 2)
(
V
IN
−
V
O
)
V
DO
I
GND
I
STBY
I
ADJ
I
EN
V
EN(IH)
V
EN(IL)
I
OUT(SC)
PSRR
Ground Pin Current
Adjust Input Bias Current
Enable Pin Current
Enable Threshold
Short Circuit Current Limit
Power Supply Rejection Ratio
Output Noise
Thermal Shutdown Temperature
0.175
0.25
280
V
µA
nA
nA
V
mA
dB
µV
°C
e
N
T
SD
E
LECTRICALS
E
LECTRICALS
Note 2: Dropout voltage is defined as the input to output differential at which the output voltage drops 1% below the nominal value. Dropout voltage specification
applies only to output voltages greater than 2.8V. For output voltages below 2.8V, the dropout voltage is nothing but the input to output differential, since the
minimum input voltage is 2.8V.
Copyright
©
2000
Rev. 1.1a, 2006-01-19
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX8221
TM
®
Dual 150mA CMOS Low Dropout Regulator
P
RODUCTION
D
ATA
S
HEET
APPLICATIONS
WWW .
Microsemi
.C
OM
Description
The LX8221 family of LDO linear regulators is available
in a 10-pin MSOP Package and provides a cost effective
power management solution for battery driven applications.
The regulator family includes both fixed/adjustable and
adjustable/adjustable output voltage versions. The internal
PMOS power device provides low dropout regulation with
a fast line and load transient response. It also includes
internal current limiting and thermal shutdown circuitry. In
this section you will find information about capacitor,
thermal, and layout design considerations.
Input Capacitor
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 this capacitor to ensure that the capacitor’s
value will be around 1
µ
F over the entire operating
temperature range. For the LX8221, a 1
µ
F ceramic type
capacitor may be connected between both VIN1/2 and
ground.
Output Capacitor
The LX8221 uses an internal feedback loop to maintain a
constant output voltage. This feedback loop induces a
natural phase shift and the amount of phase shift
determines the loop’s stability. Therefore, like any low-
dropout regulator, an output capacitor with low ESR
(Equivalent Series Resistance) is required between VOUT
and GND to stabilize the internal control loop. A ceramic,
tantalum or electrolytic capacitor with a minimum
recommended capacitance value of 1.0
µ
F and ESR between
5mΩ and 1Ω will satisfy the stability for the entire
operating range.
Optional Bypass Capacitor
The fixed/adjustable voltage version of the LX8221
includes a separate Bypass pin (CB1) for the fixed
regulator that allows for further reduction of output noise.
If the regulator’s output noise performance meets system
design specifications without the capacitor, omit it. The
bypass capacitor impacts the start up time, which is
inversely proportional to the size of bypass capacitor.
Further, the bypass capacitor reduces the regulator phase
margin. Hence, implementing the bypass capacitor will
require the use of a larger output capacitor to maintain the
LDO’s stability. The LX8221-x adjustable regulator’s
output voltage can be externally set by connecting the ADJ
pin/s to an external resistor divider (See Figure 1 and 2).
The output voltage can be calculated using the formula:
⎛
R
⎞
V
OUT
=
V
ADJ
⎜
1
+
1
⎟
⎜
R
⎟
2
⎠
⎝
Enable
The Enable pin allows the LX8221 to be independently
turned on and off. The Enable pins are compatible with
standard TTL-CMOS levels. A logic zero (0.4V) on the En
1
/
En
2
pins shuts the LX8221 off and reduces the supply
current to less than 1µA (typical). Pulling the Enable inputs
high (2.0V) causes normal operation to resume. If the Enable
feature is not used, this pin can be connected to V
IN
.
Minimum Load Requirement
Although line regulation is improved with a minimum load
of 100µA, the LX8221 does not have a minimum load
current in order to maintain stability. This is an especially
important feature in certain applications.
Temperature Protection
The thermal protection shuts the LX8221 down when the
junction temperature exceeds approximately 150°C; there is
no appreciable thermal hysteresis.
Short Circuit Current Protection
The LX8221 includes over-current protection, when the
output load current exceeds about 400mA. When this
occurs, the protection circuit forces the regulator to decrease
its output current.
Thermal Consideration
Thermal shutdown protects the integrated circuit from
thermal overload caused from a rise in junction temperature
during power dissipation. This type 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 T
J
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 each regulator can
A
PPLICATIONS
A
PPLICATIONS
Copyright
©
2000
Rev. 1.1a, 2006-01-19
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX8221
TM
®
Dual 150mA CMOS Low Dropout Regulator
P
RODUCTION
D
ATA
S
HEET
APPLICATIONS
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Microsemi
.C
OM
be calculated using the following equation:
P
D
=
(
V
IN
(
MAX
)
−
V
OUT
(
MIN
)
)
×
I
OUT
(
MAX
)
calculate the
temperature:
total
power
dissipation
and
junction
Total Power Dissipation:
P
D
=
(
4.2V
−
2.7 V
)
×
0.1A
=
0.15 W
(Note: power dissipation resulting from quiescent current
is negligible)
For the MSOP package, thermal resistance,
θ
JA
is 206°C/W
when mounted on a FR4 copper clad PCB. Junction
temperature of the integrated circuit can be calculated
using:
T
J
=
T
A
+
T
RISE
Junction Temperature:
T
J
=
60
o
C
+
0.15
W
×
206
o
C
/
W
=
91
o
C
(
)
Where:
T
RISE
=
(
P
D
× Θ
JA
)
Example:
Given the following conditions:
T
A
= 60°C
V
IN
= 4.2V
V
OUT
= 2.7V
I
OUT
= 100mA
Layout Consideration:
The layout must be implemented with low impedance paths
for V
IN
, V
OUT
and Ground by creating sufficiently wide
traces to avoid voltage drops and pick up noise. Adding an
area of PCB copper to the GND pin (pin 8) will reduce the
overall
θ
JA
since it is thermally connected to the device
substrate. This will lower the device junction temperature
improving overall output voltage accuracy. The input/output
capacitors must be placed as close as possible to each
voltage regulator output pin.
A
PPLICATIONS
A
PPLICATIONS
Copyright
©
2000
Rev. 1.1a, 2006-01-19
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
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