SECOS SSC2138

SSC2138
1.5A CMOS
Low Dropout Voltage Regulator
Elektronische Bauelemente
RoHS Compliant Product
Description
The SSC2138 positive,linear regulators feature low quiescent
current (45µA typ.) with low dropout voltage, making them ideal
for battery applications. Output voltage are set at the factory and
trimmed to 1.5% accuracy.These rugged devices have both
Thermal Shutdown and Current Fold-back to prevent device failure
under the "Worst" of operating conditions.The SSC2138 is stable
with an output capacitance of 4.7µF or greater.
Features
* Low Temperature Coefficient
* Over-Temperature Shutdown
* Adjustable Version
* Very Low Dropout Voltage
* High Accurate ± 1.5%
* Short Circuit Current Fold-back
* Guaranteed 1.5A output
* Current Limiting
* Power-Saving Shutdown Mode
REF.
A
B
C
D
E
F
Millimeter
Min.
Max.
5.80
4.80
3.80
0
0.40
0.19
6.20
5.00
4.00
8
0.90
0.25
REF.
M
H
L
J
K
G
Millimeter
Min.
Max.
0.10
0.25
0.35
0.49
1.35
1.75
0.375 REF.
45
1.27 TYP.
Applications
* PC Peripherals
* Wireless Devices
* Portable Electronics
* Battery Powered Widgets
* Instrumentation
Functional Block Diagram
Typical Application Circuit
SSC2138
http://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 1 of 7
SSC2138
1.5A CMOS
Elektronische Bauelemente
Low Dropout Voltage Regulator
Absolute Maximum Ratings
Parameter
Ratings
Symbol
Unit
Input Voltage
VIN
8
V
Output Current
IOUT
PD/(VIN-VO)
mA
Output Voltage
VOUT
Operating Ambient Temperature
Topr
Max. Junction Temperature
Power Dissipation (
o
C
mW
B
o
Electrical Characteristics Ta=25 C unless otherwise noted (V
Parameter
Symbol
1
Min.
Typ.
2
VOUT (T)
Output Voltage
VOUT (E)
-1.5%
Output Current
IO
1.5
_
Current Limit
ILIM
1.5
2.0
REGLOAD
-1
0.2
Load Regulation
VDROPOUT
Ground Pin Current
IGND
_
_
_
_
_
_
_
45
-0.15
Line Regulation
C
o
810
PD
EDS Classification
Dropout Voltage
C
o
-40~+125
150
Tj Max.
T=100 C)
o
-40~+85
Tj
Junction Temperature
V
Gnd-0.3 to VIN+0.3
REGLINE
-0.1
Input Voltage
Over Temperature Shutdown
Unit
1.5%
V
A
_
_
1
800
0.15
0.02
0.1
%
IO=1mA~1.5A
1.5V<VOUT(T) ≤ 2.0V
2.0V<VOUT(T) ≤ 2.8V
mV
2.8V<VOUT(T)
%
Io=1mA
VIN=VOUT(T)+ 1
2.0V ≤ VOUT(T)<4.0V
to
VOUT(T)+2
4.0V≤ VOUT(T)
VOUT(T)< 2.0V
Note
_
7
OTS
_
o
o
150
_
30
_
V
C
C
Over Temperature Hystersis
OTH
Output Voltage
Temperature Coefficient
TC
_
30
_
ppm/ C
Short Circuit Current
ISC
_
750
_
mA
Power Supply Rejection
Output Voltage Noise
EN Input Threshold
50
_
_
20
_
eN
_
30
_
VEH
2
_
VEL
0
_
PSRR
_
VIN
0.4
IEH
_
_
IEL
_
_
0.5
Shutdown Supply Current
ISD
_
0.5
2
ADJ Input Bias Current
IADJ
_
1
_
1
_
_
1.223
1.242
1.261
EN Input Bias Current
Min. Load Current
ADJ Reference Voltage
IMIN
VREF
0.1
Vo=VOUT(E)-2%
IO=1mA~1.5A
0.4
_
Io=1.5A
uA
VIN
3
Condition
VO>1.2V
A
600
_
=VOUT(T)+2V,VEN=VIN )
VEN=VENmin,IO=1mA
VO>1.2V
1300
_
_
-0.4
Max.
IN
o
dB
uVrms
V
uA
VOUT<0.4V
Io=100mA
f=1kHz
Co=4.7uF
f=10kHz
(ceramic)
f=10Hz~100kHz, Io=10mA
CO=4.7uF
VIN=2.7V to 7V
VIN= 7V
VEN=0V,VIN= 7V
uA
VIN=5V,VOUT=0V,VEN=0V
uA
VIN=5V,VADJ=1.242V
mA
V
Note 1: VOUT (E) =Effective Output Voltage (i.e. the output voltage when "VOUT (T) +2.0V" is provided at the VIN pin while maintaining a
certain IOUT value).
2: VOUT (T) =Specified Output Voltage
3: VIN (MIN) =VOUT+V DROPOUT
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01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 2 of 7
SSC2138
1.5A CMOS
Low Dropout Voltage Regulator
Elektronische Bauelemente
Ordering Information(contd.)
Part Number
SSC2138-AD
Marking
Output Voltage
8CAD2
XXXX
Adjustable
Part Number
Marking
Output Voltage
Detailed Description
The SSC2138 of COMS regulators contain a PMOS pass transistor,voltage reference, error amplifier,over-current protection and thermal
shutdown.The P-channel pass transistor receives data from the error amplifier, over-current shutdown, and thermal protection circuits.
During normal operation, the error amplifier compares the output voltage to a precision reference. Over-current and Thermal shutdown circuits
o
become active when the junction temperature exceeds140 C, or the current exceeds 2.2A. During thermal shutdown, the output voltage
remains low. Normal operation is restored when the junction temperature drops below 120oC.The SSC2138 behaves like a current
source when the load reaches 2.2A. However, if the load impedance drops below 0.3 Ω , the current drops back to 600mA to prevent
excessive power dissipation. Normal operation is restored when the load resistance exceeds of 0.75 Ω .
External Capacitors
The SSC2138 is stable with an output capacitance to ground of 4.7uF or greater. Ceramic capacitors have the lowest ESR, and will
offer the best AC performance. Conversely, Aluminum Electrolytic capacitors exhibit the highest ESR, resulting in the poorest AC
response. Unfortunately, large value ceramic capacitors are comparatively expensive. One option is to parallel a 0.1uF ceramic
capacitor with a 10uF Aluminum Electrolytic. The benefit is low ESR, high capacitance, and low overall cost. A second capacitor is
recommended between the input and ground to stabilize VIN. The input capacitor should be at least 0.1uF to have a beneficial
effect. All capacitors should be placed in closed proximity to the pins. A "Quiet" ground termination is desirable. This can be
achieved with a "Star" connection.
Enable
When EN pin is pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered down. In this state, the quiescent
current is less than 2uA. This pin behaves much like an electronic switch. 100KΩ resistor is necessary between VEN source and EN
pin when VEN is higher than VIN. (Note: There is no internal pull-up for EN pin.)
Adjustable Version
The adjustable version uses external feedback resistors to generate an output voltage anywhere from 1.5V to 5.0V. Vadj is trimmed to
1.242V and Vout is given by the equation:
VOUT=Vadj*(1+R1/R2)
Feedback resistors R1 and R2 should be high enough to keep quiescent current low, but increasing R1+R2 will reduce stability. In general,
R1 and R2 in the 10's of k Ω will produce adequate stability, given reasonable layout precautions. To improve stability characteristics,
keep parasitic on the ADJ pin to min., and lower R1 and R2 values.
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01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 3 of 7
SSC2138
1.5A CMOS
Elektronische Bauelemente
Low Dropout Voltage Regulator
Characteristics Curve
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01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 4 of 7
SSC2138
1.5A CMOS
Elektronische Bauelemente
http://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Low Dropout Voltage Regulator
Any changing of specification will not be informed individual
Page 5 of 7
SSC2138
1.5A CMOS
Elektronische Bauelemente
ht tp://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Low Dropout Voltage Regulator
Any changing of specification will not be informed individual
Page 6 of 7
SSC2138
1.5A CMOS
Low Dropout Voltage Regulator
Elektronische Bauelemente
External Resistor Divider Table
R1(kΩ)
VOUT
1
2
1.30
21.41
1.35
11.50
1.40
5
10
20
50
R1(kΩ)
VOUT
1
42.83 107.07 214.14 428.28 1070.7
3.20
0.63
1.27
3.17
6.34
12.69
31.72
23.00
57.50 115.00 230.00 575.00
3.25
0.62
1.24
3.09
6.19
12.37
30.93
7.86
15.72
39.30
78.61 157.22 393.04
3.30
0.60
1.21
3.02
6.03
12.07
30.17
1.45
5.97
11.94
29.86
59.71 119.42 298.56
3.35
0.59
1.18
2.95
5.89
11.78
29.46
1.50
4.81
9.63
24.07
48.14
96.28 240.70
3.40
0.58
1.15
2.88
5.76
11.51
28.78
1.55
4.03
8.06
20.16
40.32
80.65 201.62
3.45
0.56
1.13
2.81
5.63
11.25
28.13
1.60
3.47
6.94
17.35
34.69
68.39 173.46
3.50
0.55
1.10
2.75
5.50
11.00
27.50
1.65
3.04
6.09
15.22
30.44
60.88 152.21
3.55
0.54
1.08
2.69
5.38
10.76
26.91
1.70
2.71
5.42
13.56
27.12
54.24 135.59
3.60
0.53
1.05
2.63
5.27
10.53
26.34
1.75
2.44
4.89
12.22
24.45
48.90 122.24
3.65
0.52
1.03
2.58
5.16
10.32
25.79
1.80
2.23
4.45
11.13
22.26
44.52 111.29
3.70
0.51
1.01
2.53
5.05
10.11
25.26
1.85
2.04
4.09
10.21
20.43
40.86 102.14
3.75
0.50
0.99
2.48
4.95
9.90
24.76
1.90
1.89
3.78
9.44
18.88
37.75
94.38
3.80
0.49
0.97
2.43
4.86
9.71
24.28
1.95
1.75
3.51
8.77
17.54
35.08
87.71
3.85
0.48
0.95
2.38
4.76
9.52
23.81
2.00
1.64
3.28
8.19
16.39
32.77
81.93
3.90
0.47
0.93
2.34
4.67
9.35
23.36
2.05
1.54
3.07
7.69
15.37
30.74
76.86
3.95
0.46
0.92
2.29
4.59
9.17
22.93
2.10
1.45
2.90
7.24
14.48
28.95
72.38
4.00
0.45
0.90
2.25
4.50
9.01
22.52
2.15
1.37
2.74
6.84
13.68
27.36
68.39
4.05
0.44
0.88
2.21
4.42
8.85
22.12
2.20
1.30
2.59
6.48
12.96
25.93
64.82
4.10
0.43
0.87
2.17
4.35
8.69
21.73
2.25
1.23
2.46
6.16
12.32
24.65
61.61
4.15
0.43
0.85
2.14
4.27
8.54
21.35
2.30
1.17
2.35
5.87
11.74
23.48
58.70
4.20
0.42
0.84
2.10
4.20
8.40
20.99
2.35
1.12
2.24
5.60
11.21
22.42
56.05
4.25
0.41
0.83
2.06
4.13
8.26
20.64
2.40
1.07
2.15
5.36
10.73
21.45
53.63
4.30
0.41
0.81
2.03
4.06
8.12
20.31
2.45
1.03
2.06
5.14
10.28
20.56
51.41
4.35
0.40
0.80
2.00
4.00
7.99
19.98
2.50
0.99
1.97
4.94
9.87
19.75
49.36
4.40
0.39
0.79
1.97
3.93
7.87
19.66
2.55
0.95
1.90
4.75
9.50
18.99
47.48
4.45
0.39
0.77
1.94
3.87
7.74
19.36
2.60
0.91
1.83
4.57
9.15
18.29
45.73
4.50
0.38
0.76
1.91
3.81
7.62
19.06
2.65
0.88
1.76
4.41
8.82
17.64
44.11
4.55
0.38
0.75
1.88
3.75
7.51
18.77
2.70
0.85
1.70
4.26
8.52
17.04
42.59
4.60
0.37
0.74
1.85
3.70
7.40
18.49
2.75
0.82
1.65
4.12
8.24
16.47
41.18
4.65
0.36
0.73
1.82
3.64
7.29
18.22
2.80
0.80
1.59
3.99
7.97
15.94
39.86
4.70
0.36
0.72
1.80
3.59
7.18
17.96
2.85
0.77
1.54
3.86
7.72
15.45
38.62
4.75
0.35
0.71
1.77
3.54
7.08
17.70
2.90
0.75
1.50
3.75
7.49
14.98
37.45
4.80
0.35
0.70
1.75
3.49
6.98
17.45
2.95
0.73
1.45
3.64
7.27
14.54
36.36
4.85
0.34
0.69
1.72
3.44
6.88
17.21
3.00
0.71
1.41
3.53
7.06
14.13
35.32
4.90
0.34
0.68
1.70
3.40
6.79
16.98
3.05
0.69
1.37
3.43
6.87
13.74
34.35
4.95
0.33
0.67
1.67
3.35
6.70
16.75
3.10
0.67
1.34
3.34
6.68
13.37
33.42
5.00
0.33
0.66
1.65
3.30
6.61
16.52
3.15
0.65
1.30
3.25
6.51
13.02
32.55
R2(k Ω)=(1.242*R1(k Ω))/(VOUT-1.242)
2
5
10
20
50
R2(kΩ)=(1.242*R1(k Ω))/(VOUT-1.242)
Note: Small load (greater than 2mA) is necessary as R1 or R2 is larger than 50k Ω. Otherwise, output voltage probably can not be pulled
down to 0V on disable mode.
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01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 7of 7