POWER MANAGEMENT
Description
The SC2982 is a 50mA ultra low dropout linear
regulator with a built in CMOS/TTL logic level enable
switch. It is designed specifically for battery powered
applications where low quiescent current and low
dropout are critical for battery longevity.
50mA Ultra Low Dropout, Low
Noise Micropower Linear Regulator
PRELIMINARY
Features
Ultra low dropout voltage - 100mV @ 50mA
Guaranteed 50mA output current
Low ground pin current at all loads
<1µA quiescent current in shutdown
Wide input supply voltage range 2.5V to 16V
Wide output voltage range
Excellent line regulation
Industrial temperature range
Surface mount packaging (5 pin SOT-23)
SC2982
u
u
u
u
u
u
The SC2982 uses a Semtech proprietary internal PNP
device for the pass element, providing a low dropout
u
voltage of 100mV at a load of 50mA, while maintaining a
u
u
ground pin current of 600µA.
The output noise is reduced by placing a 10nF capacitor
on pin 4 (bypass).
Applications
Battery Powered Systems
Cellular Telephones
Cordless Telephones
Pagers
Personal Digital Assistants
Portable Instrumentation
Cameras
Portable Consumer Equipment
PCMCIA Cards
u
u
Each device contains a bandgap reference, error
u
amplifier, PNP pass element, thermal and current
u
limiting circuitry and resistor divider network for setting
u
output voltage.
u
The SC2982 is packaged in a 5 pin SOT-23 surface mount
u
package for a very small footprint and requires only a
u
1µF capacitor on the output for a minimum number of
u
external components.
Typical Application Circuit
U1 SC2982
1
VIN
2
3
EN
+
C
IN
1uF
VIN
GND
EN
BYP
4
Co
1uF
VO
5
VO
+
C
BYP
10nF
Notes:
(1) C
IN
is needed if the device is far from the supplys filter capacitors, or for operation from a battery. A value of 1µF
or greater should be used. C
IN
may be a tantalum or aluminum electrolytic capacitor.
(2) C
O
should be a 1µF or greater tantalum or aluminum electrolytic capacitor. Larger value capacitors will improve
the overall transient response. Due to their very low ESR, ceramic capacitors should not be used.
(3) C
BYP
should be placed as close as possible to pin 4 and ground. A 10nF ceramic capacitor is recommended.
(4) EN should be tied to VIN if the shutdown feature is not required. Maximum EN voltage = VIN.
Revision 1, January 2001
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SC2982
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
Input Supply Voltage
Power D i ssi pati on
Thermal Resi stance Juncti on to Ambi ent
Thermal Resi stance Juncti on to C ase
Operati ng Ambi ent Temperature Range
Operati ng Juncti on Temperature Range
Storage Temperature Range
Lead Temperature (Solderi ng) 10 Sec
ESD Rati ng (Human Body Model)
Sy mbol
VIN
P
D
q
JA
q
JC
T
A
T
J
T
STG
T
LEAD
V
ESD
PRELIMINARY
Maximum
-0.3 to +20
Internally Li mi ted
256
81
-40 to +85
-40 to +125
-65 to +150
300
2
U nits
V
W
°C /W
°C /W
°C
°C
°C
°C
kV
Electrical Characteristics
Unless specified: VIN = VO
(NOM)
+ 1V, I
O
= 100µA, C
O
= 1µF, V
EN
³
1.8V. Values in
bold
apply over the full operating temperature range.
Parameter
Supply Voltage Range
Output Voltage
Sy mbol
VIN
VO
Test C onditions
Min
2.5
-1
-3
Ty p
Max
16
+1
+3
U nits
V
%
Output Voltage Temperature
C oeffi ci ent
Li ne Regulati on
TC
REG
(LINE)
VIN = (VO
(NOM)
+ 1V) to 16V
40
0.06
0.12
0.15
ppm/°C
%/V
Load Regulati on
REG
(LOAD)
I
O
= 0.1mA to 50mA
0.001
0.004
0.007
%/mA
D ropout Voltage
(1)
V
D
I
O
= 100µA
5
10
25
mV
I
O
= 50mA
100
150
200
mV
Ground Pi n C urrent
I
GND
I
O
= 100µA
80
125
150
µA
I
O
= 50mA
600
1000
1500
µA
V
EN
< 0.4V (shutdown)
ã
2001 Semtech Corp.
2
0.01
5
µA
www.semtech.com
SC2982
POWER MANAGEMENT
Electrical Characteristics
Parameter
C urrent Li mi t
(2)
Ri pple Rejecti on Rati o
Thermal Regulati on
RMS Output Noi se
Enable Input Voltage
Sy mbol
I
LIM
PSRR
Test C onditions
VO > (VO
(NOM)
- 5%)
I
O
= 100µA, f = 100Hz, C
BYP
= 10nF,
C
O
= 10µF
Min
200
50
0.05
B
W
= 300Hz to 50kHz, I
O
= 1mA,
C
BYP
= 10nF, C
O
= 10µF
Low = O/P OFF
Hi gh = O/P ON
Enable Input C urrent
I
EN
V
EN
£
0.4V
V
EN
³
1.8V
1.8
-0.01
5
-1
10
20
30
0.4
Ty p
PRELIMINARY
Unless specified: VIN = VO
(NOM)
+ 1V, I
O
= 100µA, C
O
= 1µF, V
EN
³
1.8V. Values in
bold
apply over the full operating temperature range.
Max
U nits
mA
db
%/W
µVrms
V
V
µA
µA
∆
V
O
(%)
P
D
e
no
V
EN
Notes:
(1) Defined as the input to output differential at which the output voltage drops 100mV below the value measured
at a differential of 1V.
(2) As the load resistance further decreases, the SC2982 folds back the output current to approximately 150mA at
V
O
= 0V.
ã
2001 Semtech Corp.
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SC2982
POWER MANAGEMENT
Pin Configuration
PRELIMINARY
Ordering Information
D ev ice
SC 2982C SK-X.XTR
(1)(2)
P ackag e
5 pi n SOT-23
Notes:
(1) Where -X.X denotes voltage options. Available
voltages are: 1.8V, 2.5V, 2.8V, 3.0V, 3.3V, 3.6V, 3.8V,
4.0V and 5.0V.
(2) Only available in tape and reel packaging. A reel
contains 3000 devices.
Block Diagram
Pin Descriptions
Pin
1
2
3
4
5
Pin N ame
VIN
GND
EN
BYP
VO
Pin Function
Supply voltage i nput.
Ground.
Acti ve hi gh enable i nput. C onnect to VIN i f not bei ng used.
Reference bypass. C onnect a 10nF capaci tor between thi s pi n and GND to reduce output noi se
Voltage output.
ã
2001 Semtech Corp.
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