1 (9)
DA9485.001
7 March, 2001
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
Vrms,
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
s typical without
bypass capacitor.
A very wide range of values of Equivalent Series
Resistance (ESR) of output capacitors can be used
with MAS9485. This ESR range from a few m
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
1
2
3
4
5
VIN
VOUT
CTRL
GND
BYPASS
Top View
G = Ground, I = Input, O = Output, P = Power
For Top Marking Information see
p. 9 Ordering Information
2 (9)
DA9485.001
7 March, 2001
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 listed may cause permanent damage to the device. The device may not operate under these conditions, but it will
not be destroyed.
CTRL
VIN
VOUT
GND
OVER CURRENT /
OVER TEMPERATURE
PROTECTION
VOLTAGE
REFERENCE
+
BYPASS
80k
3 (9)
DA9485.001
7 March, 2001
ELECTRICAL CHARACTERISTICS
T
A
= 27C, V
IN
= Typ V
OUT
+ 1.0 V, I
OUT
= 1.0 mA, C
IN
= 1.0
F, C
OUT
= 1.0
F, V
CTRL
= V
IN
, unless otherwise specified
x
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
o
C prevents the device from turning on too soon after thermal shut-down.
x
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
A
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
x
Current Parameters
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
Continuous Output Current
I
OUT
100
mA
Short Circuit Current
I
MAX
R
L
= 0
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
A
4 (9)
DA9485.001
7 March, 2001
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
T
T
P
-
=
mW
Note 1
Note 1: T
J(MAX)
denotes maximum operating junction temperature (+125C), T
A
ambient temperature, and R
JA
junction-to-air thermal
resistance (+260C/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
Vrms
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
s
Overshoot
V
CTRL
= 0 to 2.4 V
w/o C
BYPASS
3
5
%
Start-up Delay
V
CTRL
to V
OUT
60
s
PDF 
ZIP