TS2940 - PS electronic
TS2940
1A Ultra Low Dropout Fixed Positive Voltage Regulator
TO-263
Low Dropout Voltage 0.6V (typ.)
Pin assignment:
1. Input
2. Ground
3. Output
General Description
The TS2940 series of fixed-voltage monolithic micro-power voltage regulators is designed for a wide range of
applications. This device excellent choice of use in battery-power application. Furthermore, the quiescent current
increases on slightly at dropout, which prolongs battery life.
This series of fixed-voltage regulators features very low ground current (100uA Typ.) and very low drop output voltage
(Typ. 60mV at light load and 600mV at 1A). This includes a tight initial tolerance of 1% typ., extremely good line
regulation of 0.05% typ., and very low output temperature coefficient.
This series is offered in 3-pin TO-263, TO-220, TO-252 & SOT-223 package.
Features

Dropout voltage typically 0.6V @Io=1A

+30V Input over voltage protection

Output current up to 1A

+60V Transient peak voltage

Output voltage trimmed before assembly

Internal current limit

-18V Reverse peak voltage

Thermal shutdown protection
Block Diagram
Ordering Information
Part No.
Operation Temp.
TS2940CZxx
Package
TO-220
TS2940CMxx
o
-40 ~ +125 C
TS2940CPxx
TS2940CWxx
TO-263
TO-252
SOT-223
Note: Where xx denotes voltage option, available are
5.0V, 3.3V, 2.5V and 1.8V. Contact factory for
additional voltage options.
Absolute Maximum Rating (Note 1)
Input Supply Voltage (Note 2)
Vin (impulse)
-18 ~ +60
V
Input Supply Voltage
Vin
26
V
Power Dissipation (Note 3)
PD
Internally Limited
Operating Junction Temperature Range
TJ
Storage Temperature Range
TSTG
W
-40 ~ +125
o
C
-65 ~ +150
o
C
o
Lead Soldering Temperature (260 C)
TS2940
TO-220 TO-263 Package
5
TO-252 / SOT-223Package
4
1-6
S
2003/12 rev. C
Electrical Characteristics
o
Vin = Vout + 5V, IL = 5mA, Co = 10uF, Ta = 25 C, unless otherwise specified.
Parameter
Conditions
Output Voltage
Output Voltage
Min
0.980|Vo|
5mA ≤ IL ≤ 800mA,
Vo+5V ≤ Vin ≤ 26V
Output Voltage Temperature
Coefficient
Typ
5.0 / 3.3
Max
Unit
1.020|Vo|
V
0.970|Vo|
2.5 / 1.8
1.030|Vo|
V
--
50
150
ppm/ C
o
Line Regulation
Vo+2V ≤ Vin ≤ 26V
--
0.05
0.5
%
Load Regulation
5mA ≤ IL ≤ 800mA
--
0.2
1.0
%
IL=100mA
--
100
200
IL=500mA
--
300
500
IL=800mA
--
600
800
IL=5mA
--
10
--
IL=800mA
--
30
--
Vout=0
--
--
1.5
CL=2.2uF
--
500
--
CL=3.3uF
--
350
--
CL=33uF
--
120
--
Dropout Voltage (Note 4)
Quiescent Current (Note 5)
Short Circuit Current (Note 6)
Output Noise,
10Hz to 100KHz, IL=10mA
mV
mA
A
uVrms
Thermal Performance
Condition
Package type
Typ
Thermal Resistance
TO-220
60
Junction to Ambient
TO-263
80
TO-252
150
SOT-223
170
Unit
o
C/W
Note 1: Absolute Maximum Rating is limits beyond which damage to the device may occur. For guaranteed specifications
and test conditions see the Electrical Characteristics.
Note 2: Maximum positive supply voltage of 60V must be limited duration (<100mS) and duty cycle (<1%).
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, Tj, the junction to
ambient thermal resistance, θja, and the ambient temperature, Ta. Exceeding the maximum allowable power
dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. The effective
value of θja can be reduced by using a heatsink.
Note 4: Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its
nominal value measured at 1V differential.
Note 5: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the
ground pin current and output load current.
Note 6: Output current will decrease with increasing temperature, but it will be not dropped below 1A at the maximum
specified temperature.
TS2940
2-6
2003/12 rev. C
Application Information
The TS2940 series is a high performance with low
dropout voltage regulator suitable for moderate to high
current and voltage regulator application. Its 600mA(typ)
dropout voltage at full load and over temperature makes it
especially valuable in battery power systems and as high
efficiency noise filters in post regulator applications.
Unlike normal NPN transistor design, where the base to
emitter voltage drop and collector to emitter saturation
voltage limit the minimum dropout voltage, dropout
performance of the PNP output of these devices is limited
only by low Vce saturation voltage.
The TS2940 series is fully protected from damage due to
fault conditions. Linear current limiting is provided. Output
current during overload conditions is constant. Thermal
shutdown the device when the die temperature exceeds
the maximum safe operating temperature. Transient
protection allows device survival even when the input
voltage spikes above and below nominal. The output
structure of these regulators allows voltages in excess of
the desired output voltage to be applied without reverse
current flow.
Typical Application Circuit
A low ESR solid tantalum capacitor works extremely
well and provides good transient response and
stability over temperature. Aluminum electrolytic can
also be used, as long as the ESR of the capacitor is
<2ohm. The value of the output capacitor can be
increased without limit. Higher capacitance values
help to improved transient response and ripple
rejection and reduce output noise.
Minimum Load Current
The TS2940 series is specified between finite loads.
If the output current is too small leakage currents
dominate and the output voltage rises. A 10mA
minimum load current is necessary for proper
regulation.
Input Capacitor
An input capacitor of 1uF or greater is
recommended when the device is more that 4
inches away from the bulk AC supply capacitance or
when the supply is a battery. Small and surface
mount ceramic chip capacitors can be used for
bypassing. Larger values will help to improve ripple
rejection by bypassing the input to the regulator,
further improving the integrity of the output voltage.
Thermal Characteristics
A heatsink may be required depending on the
maximum power dissipation and maximum ambient
temperature of the application. Under all possible
operating conditions, the junction temperature must
be within the range specified under absolute
maximum ratings. To determine if the heatsink is
required, the power dissipated by the regulator, PD
must be calculated.
Output Capacitor
The TS2940 series requires an output capacitor to
maintain stability and improve transient response. Proper
capacitor selection is important to ensure proper
operation. The output capacitor selection is dependent
upon the ESR of the output capacitor the maintain
stability. When the output capacitor is 10uF or greater, the
output capacitor should have an ESR less than 2 ohm.
This will improve transient response as well as promoted
stability. Ultra low ESR capacitors (<100mohm), such as
ceramic chip capacitors may promote instability. These
very low ESR levels may cause an oscillation and/or
under damped transient response.
The below formula shows the voltages and currents
for calculating the PD in the regulator:
Iin = IL / IG
PD = (Vin-Vout) * IL + (Vin) * IG
Ex. PD = (3.3V-2.5V) * 1A + 3.3V * 11mA
= 800mW + 36mW
= 836mW
Remark: IL is output load current,
IG is ground current.
Vin is input voltage
Vout is output voltage
TS2940
3-6
2003/12 rev. C
Application Information (continued)
The next parameter which must be calculated is the
maximum allowable temperature rise, TR(max). this is
calculated by the using to formula:
TR(max) = TJ(max) – TA (max)
Where: TJ(max) is the maximum allowable junction
o
temperature, which is 125 C for commercial
grade parts.
IMPORTANT: if the maximum allowable value for is
o
found to be ≥60 C/W for the TO-220 package, ≥80
o
o
C/W for the TO-263 package, ≥150 C/W for the TOo
252 package, or ≥170 C/W for the SOT-223 package,
no heatsink is needed since the package alone will
dissipate enough heat to satisfy these requirements. If
the calculated value for θja falls below these limits, a
heatsink is required.
TA(max) is the maximum ambient temperature
which will be encountered in the application.
Using the calculated values for TR(max) and PD, the
maximum allowable value for the junction to ambient
thermal resistance, θja, can now be found:
θja = TR(max) / PD
TS2940
4-6
2003/12 rev. C
TO-220 Mechanical Drawing
K
K
B
L
L
DIM
C
C
AB
A
P
P
J
J
I
I
M
D
D
E
H
E
F
G
F
G
O
O
N
N
TO-220 DIMENSION
MILLIMETERS
INCHES
MIN
MAX
MIN
MAX
A
10.000
10.500
0.394
0.413
B
3.240
4.440
0.128
0.175
C
2.440
2.940
0.096
0.116
D
-
6.350
-
0.250
E
0.381
1.106
0.015
0.040
F
2.345
2.715
0.092
0.058
GM
4.690
5.430
0.092
0.107
H
12.700
14.732
0.500
0.581
I
8.382
9.017
0.330
0.355
J
14.224
16.510
0.560
0.650
K
3.556
4.826
0.140
0.190
L
0.508
1.397
0.020
0.055
M
27.700
29.620
1.060
1.230
N
2.032
2.921
0.080
0.115
O
0.255
0.610
0.010
0.024
P
5.842
6.858
0.230
0.270
TO-263 Mechanical Drawing
E
F
A
E
F
A
I
H
B
I
H
B
DIM
D
G
MILLIMETERS
INCHES
MIN
MAX
MIN
MAX
A
10.000
10.500
0.394
0.413
B
14.605
15.875
0.575
0.625
C
0.508
0.991
0.020
0.039
D
2.420
2.660
0.095
0.105
E
4.064
4.830
0.160
0.190
F
1.118
1.400
0.045
0.055
G
0.450
0.730
0.018
0.029
H
8.280
8.800
0.325
0.346
I
1.140
1.400
0.044
0.055
J
1.480
1.520
0.058
0.060
G
C
TO-263 DIMENSION
C
D
TS2940
5-6
2003/12 rev. C
H
TO-252 Mechanical Drawing
J
E
J
E
AA
TO-252 DIMENSION
F
I
F
DIM
I
B B
G
C C
DD
H
H
MILLIMETERS
MIN
INCHES
MAX
MIN
MAX
A
6.570
6.840
0.259
0.269
B
9.250
10.400
0.364
0.409
C
0.550
0.700
0.022
0.028
D
2.560
2.670
0.101
0.105
E
2.300
2.390
0.090
0.094
F
0.490
0.570
0.019
0.022
G
1.460
1.580
0.057
0.062
GH
0.520
0.570
0.020
0.022
I
5.340
5.550
0.210
0.219
J
1.460
1.640
0.057
0.065
SOT-223 Mechanical Drawing
A
A
SOT-223 DIMENSION
B
H
B
I
C
H
C
J
K
F
G
D
F
K
D
G
E
TS2940
DIM
I
E
6-6
J
MILLIMETERS
INCHES
MIN
MAX
MIN
MAX
A
6.350
6.850
0.250
0.270
B
2.900
3.100
0.114
0.122
C
3.450
3.750
0.136
0.148
D
0.595
0.635
0.023
0.025
E
4.550
4.650
0.179
0.183
F
2.250
2.350
0.088
0.093
G
0.835
1.035
0.032
0.041
H
6.700
7.300
0.263
0.287
I
0.250
0.355
0.010
0.014
J
10°
16°
10°
16°
K
1.550
1.800
0.061
0.071
2003/12 rev. C
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement