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MAS9485
LDO Voltage Regulator IC
• 100mA Very Low Dropout Voltage
Regulator
• Low Noise
• Regulator Enable/Disable Control
• Stable Even with Low -ESR Output
Capacitor
DESCRIPTION
The MAS9485 is a low dropout voltage regulator
with an enable/disable pin, which allows device to
be turned off or on by pulling control to low or high.
Due to the low noise level of only 30 µVrms,
MAS9485 is suitable for sensitive circuits, e.g., in
portable applications. In addition to the noise levels,
MAS9485 excels in dropout voltage (150 mV typical
at 100 mA) and rise time (15 µs typical without
bypass capacitor.
A very wide range of values of Equivalent Series
Resistance (ESR) of output capacitors c an be used
with MAS9485. This ESR range from a few mΩ up
to a couple of ten Ohms combined with no minimum
output current requirement makes the usage of
MAS9485 easier and low in cost.
In order to save power the device goes into sleep
mode when the regulator is disabled. An internal
thermal protection circuit prevents the device from
overheating. Also the maximum output current is
internally limited.
FEATURES APPLICATION
• Output Accuracy <±2%
• Low Noise
• Internal Thermal Shutdown
• Short Circuit Protection
• SOT23-5 Package
• Pin Compatible with LP2985
• Output Voltage Options: 3.3 V, 2.8 V, and 2.4 V
• Cellular Phones
• Cordless Phones
• Pagers
• Battery Powered Systems
• Portable Systems
• Radio Control Systems
• Low Voltage Systems
PIN CONFIGURATION AND DESCRIPTION
Pin Name Pin Type Function
VIN 1 P Power Supply Voltage
GND 2 G Ground
CTRL 3 I Enable/Disable Pin for
Regulator (push down)
BYPASS 4 I Pin for Bypass
Capacitor
VOUT 5 O Output
123
45
VIN
VOUT
CTRLGND
BYPASS
Top View
G = Ground, I = Input, O = Output, P = Power
For Top Marking Information see
p. 9 Ordering Information
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BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
All voltages with respect to ground.
Parameter Symbol Conditions Min Max Unit
Supply Voltage V
IN
-0.3 6 V
ESD Rating Human Body Model, HBM 1.5 kV
Junction Temperature T
Jmax
+170
(limited)
°C
Operating Junction
Temperature
T
J
- 40 +125 °C
Storage Temperature T
S
-55 +150 °C
Operating Ambient
Temperature
T
A
-40 +85 °C
Stresses beyond those li sted may cause perm anent damage to the device. The device may not operate under these condi tions, but it will
not be destroyed.
CTRL
VIN
VOUT
GND
OVER CURRENT /
OVER TE MPERA TURE
PROTECTION
VOLTAGE
REFERENCE
+
BYPASS
80k
Ω
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ELECTRICAL CHARACTERISTICS
TA = 27°C, VIN = Typ V
OUT
+ 1.0 V, I
OUT
= 1.0 mA, C
IN
= 1.0 µF, C
OUT
= 1.0 µF, V
CTRL
= VIN, unless otherwise specif i ed
◆ Thermal protection
Parameter Symbol Conditions Min Typ Max Unit
Threshold high T
H
140 155 170 °C
Threshold low T
L
130 145 160 °C
The hysteresis of 10 oC prevents the device from turning on too soon after therm al shut-down.
◆ Control Terminal Specifications
Parameter Symbol Conditions Min Typ Max Unit
Control Voltage
OFF State
ON State
V
CTRL
1.6
0.55
V
Control Current I
CTRL
V
CTRL
= V
IN
V
CTRL
= 0 V
5
0
10
µA
u Voltage Parameters
Parameter Symbol Conditions Min Typ Max Unit
Output Voltage Tolerance V
OUT
2.76 2.88 V
Operating Supply Voltage V
IN
2.5 6 V
Dropout Voltage V
DROP
I
OUT
= 1 mA
I
OUT
= 50 mA
I
OUT
= 100 mA
15
70
150
mV
◆ Current Parameters
Parameter Symbol Conditions Min Typ Max Unit
Continuous Output Current I
OUT
100 mA
Short Circuit Current I
MAX
RL = 0 Ω
250 mA
Peak Output Current I
PK
V
OUT
> 95%*V
OUT
typical 210 mA
Ground Pin Current I
GND
I
OUT
= 0 mA
I
OUT
= 10 mA
I
OUT
= 50 mA
I
OUT
= 100 mA
V
CTRL
< 0.3 V
100
125
170
230
0.01
µA
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u Power Dissipation
Parameter Symbol Conditions Min Typ Max Unit
Junction to Case Thermal
Resistance
R
JC
81.0 °C/W
Junction to Ambient Thermal
Resistance
R
JA
260 °C/W
Maximum Power Dissipation P
d
any ambient temperature
JA
A
(MAX)
J
MAX
d
R
TT
P
−
=
mW
Note 1
Note 1: T
J(MAX)
denotes maximum operati ng j unction temperature (+125°C), TA ambient temperature, and RJA junction-to-air thermal
resistance (+260°C/W).
u Line and Load Regulation
Parameter Symbol Conditions Min Typ Max Unit
Line Regulation V
OUT
+ 1 V < V
IN
< 6 V
I
OUT
= 60 mA
3.0 mV
Load Regulation
I
OUT
= 1.0 to 50 mA
I
OUT
= 1.0 to 100 mA
5
10
15
20
mV
u Noise and Ripple Rejection
Parameter Symbol Conditions Min Typ Max Unit
Output Noise Voltage V
RMS
300Hz < f < 50kHz,
C
BYPASS
= 10 nF
30
µVrms
Noise Density V
N
C
BYPASS
= 10 nF, I
OUT
= 50 mA,
f = 1.0 kHz
250 nV
sqrt(Hz)
PSRR C
BYPASS
= 10 nF
f = 1kHz
f = 10 kHz
f = 100 kHz
55
45
23
dB
u Dynamic Parameters
Parameter Symbol Conditions Min Typ Max Unit
Rise Time (10%…90%) V
CTRL
= 0 to 2.4 V, I
OUT
= 30mA
C
BYPASS
= 10 nF
w/o C
BYPASS
3
15
ms
µs
Overshoot V
CTRL
= 0 to 2.4 V
w/o C
BYPASS
35 %
Start-up Delay V
CTRL
to V
OUT
60
µs
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APPLICATION INFORMATION
CTRL
VIN
VOUT
OVER CURRENT /
OVER TE MPER ATURE
PROTECTION
VOLTAGE
REFERENCE
+
C
BYPASS
80kΩ
C
IN
C
OUT
GNDBYPASS
1
2
3
4
5
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Load transient vs. VOUT capacitor ESR
Load current changes from 10mA to 90mA
during 1µs.
Load current changes from 90mA to 10mA
during 1µs.
Typical load transient for battery supply and Ceramic Capacitor, ESR≈0.1…0.2Ω.
Typical load transient for battery supply and Tantalum Capacitor, ESR≈1…3Ω
Parameter Symbol Min Max Unit Comment
Output capacitor
Capacitance
C
OUT
0.22
µF
Effective Series
Resistance
ESR 0.05 20
Ω
Good capacitor value is 0.47…2µF.
To have load transient
overshoot/undershoot small it is
recommended to use capacitor with
ESR no less than 1Ω. With smaller
ESR the regulator is stable, but load
transients can get worse.
Bypass capacitor C
BYPASS
Typically 10 nF Using this capacitor decreases
noise on regulator output. DC
leakage of capacitor should be
below 100nA.
Input Capacitor C
IN
1
µF
Any type of capacitor can be used.
Small capacitor ESR and bigger
capacitor value will make load
transient better.
When selecting capacitors, tolerance and temperature coefficient should be considered to make sure the
requirements are met.
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PACKAGE (SOT-23-5) OUTLINE
Dimension Min Max Unit
A 2.60 3.00 mm
B 1.45 1.75 mm
C 2.80 3.10 mm
D 0.00 0.15 mm
E 0.90 1.30 mm
F 0.25 0.50 mm
G 0.95ref mm
H 1.90ref mm
J 0.09 0.20 mm
K010
°
L 0.35 0.55 mm
Dimensions do not include mold flash, protrusions or gate burrs.
H
J
L
K
E
D
F
PIN 1
(TOP VIEW)
A
B
G
C
Seating Plane
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TAPE SPECIFICATIONS
Feeding Direction
8 mm
4 mm
SOT23 5ld TAPE
OTHER DIMENSIONS ACCORDING TO EIA-481 STANDARD
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ORDERING INFORMATION
Product Code Product Top Marking Package Comments
MAS9485AST2-T 2.8 V Voltage Regulator IC 85A2 SOT23-5 Tape and Reel
For more voltage options contact Micro Analog Systems Oy.
LOCAL DISTRIBUTOR
MICRO ANALOG SYSTEMS OY CONTACTS
Micro Analog Systems Oy
Kamreerintie 2, P.O.Box 51
FIN-02771 Espoo, FINLAND
Http://www.mas-oy.com
Tel. (09) 80 521
Tel. Int. +358 9 80 521
Telefax +358 9 805 3213
E-mail: info@mas-oy.com
NOTICE
Micro Analog Systems Oy reserves the right to make changes to the product s c ontai ned in thi s dat a sheet in order t o im prove the des ign or
performance and to supply the best poss ible products. Micro Analog Systems Oy assum es no responsibility for the use of any circuits
shown in this data sheet, conveys no license under any pat ent or other rights unl ess otherwise spec ified in thi s data sheet, and makes no
claim that the circ uits are free from patent infringement. Applic ations for any devices s hown in this data sheet are for illustration only and
Micro Analog Systems Oy mak es no claim or warranty that such applic ations will be suitable for t he use spec ified without further t esting or
modification.
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