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TS2940
1A Ultra Low Dropout Fixed Positive Voltage Regulator
TO-263
Low Dropout Voltage 0.6V max.
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
Output current up to 1A
Output voltage trimmed before assembly
-18V Reverse peak voltage
+30V Input over voltage protection
+60V Transient peak voltage
Internal current limit
Thermal shutdown protection
Block Diagram Ordering Information
Part No. Operation Temp.
(Ambient)
TS2940CZ-xx TO-220
TS2940CM-xx TO-263
TS2940CP-xx TO-252
TS2940CW-xx
Note: Where xx denotes voltage option, available are
5.0V, 3.3V, 2.5V and 1.8V. Contact factory for
additional voltage options.
-20 ~ +85
o
C
Package
SOT-223
Absolute Maximum Rating (Note 1)
Input Supply Voltage (Note 2) Vin -18 ~ +60 V
Operation Input Supply Voltage Vin (operate) 35V V
Power Dissipation (Note 3) PD Internally Limited W
Operating Junction Temperature Range TJ -25 ~ +150
Storage Temperature Range T
Lead Soldering Temperature (260 oC)
TO-220 TO-263 Package
TO-252 / SOT-223Package
-65 ~ +150
STG
5
4
o
C
o
C
S
TS2940 1-6 2003/12 rev. A
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Electrical Characteris t ic s
Vin = Vout + 1V, IL = 5mA, Co = 10uF, Ta = 25
o
C, unless otherwise specified.
Parameter Conditions Min Typ Max Unit
Output Voltage Over temperature 0.990|Vo| 1.010|Vo| V
Output Voltage 5mA ≤ IL ≤ 1A,
Vo+1V ≤ Vin ≤ 26V
0.980|Vo|
Input Supply Voltage -- -- 26 V
Output Voltage Temperature
-- 50 150 ppm/ oC
Coefficient
Line Regulation Vo+1V ≤ Vin ≤ 26V -- 0.05 0.5 %
Load Regulation 5mA ≤ IL ≤ 1A -- 0.2 1.0 %
Dropout Voltage (Note 4) IL=100mA
=500mA
I
L
I
=1A
L
Quiescent Current (Note 5) IL=100uA
=500mA
I
L
=1A
I
L
--
--
--
--
--
--
Short Circuit Current (Note 6) Vout=0 -- -- 1.5 A
Output Noise,
10Hz
to 100KHz, IL=10mA
=2.2uF
C
L
C
=3.3uF
L
=33uF
C
L
--
--
--
5.0 / 3.3
2.5 / 1.8
100
300
600
100
15
30
500
350
120
1.020|Vo| V
200
500
mV
800
--
--
uA
mA
--
--
--
uVrms
--
Thermal Performance
Condition Package type Typ Unit
Thermal Resistance
Junction to Ambient
TO-220 60
TO-263 80
o
C/W
TO-252 150
SOT-223 170
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. A
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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.
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.
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, P
must be calculated.
The below formula shows the voltages and currents
for calculating the P
/ IG
Iin = I
L
= (Vin-Vout) * IL + (Vin) * I
P
D
Ex. PD = (3.3V-2.5V) * 1A + 3.3V * 11mA
= 800mW + 36mW
= 836mW
Remark: IL is output load current,
is ground current.
I
G
Vin is input voltage
Vout is output voltage
in the regulator:
D
G
D
TS2940 3-6 2003/12 rev. A
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The next parameter which must be calculated is the
maximum allowable temperature rise, T
calculated by the using to formula:
T
(max) = TJ(max) – TA(max)
R
Where: T
T
Using the calculated values for T
maximum allowable value for the junction to ambient
thermal resistance, θja, can now be found:
θja = T
(max) is the maximum allowable junction
J
temperature, which is 125
grade parts.
(max) is the maximum ambient temperature
A
which will be encountered in the application.
(max) and PD, the
R
(max) / P
R
D
(max). this is
R
o
C for commercial
IMPORTANT: if the maximum allowable value for is
found to be ≥60
for the TO-263 package, ≥150
package, or ≥170
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.
o
C/W for the TO-220 package, ≥80 oC/W
o
C/W for the SOT-223 package, no
o
C/W for the TO-252
TS2940 4-6 2003/12 rev. A
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TO-220 Mechanical Drawing
A
B
C
P
J
I
D
H
F
E
G
K
L
DIM
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
M
O
N
G 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-220 DIMENSION
MILLIMETERS INCHES
MIN MAX MIN MAX
TO-263 Mechanical Drawing
A
E
DIM
F
A 10.000 10.500 0.394 0.413
B 14.605 15.875 0.575 0.625
B
I
H
C
D
G
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
TO-263 DIMENSION
MILLIMETERS INCHES
MIN MAX MIN MAX
TS2940 5-6 2003/12 rev. A
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TO-252 Mechanical Drawing
J
A
B
D
C
E
F
I
G
H
DIM
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
H 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
TO-252 DIMENSION
MILLIMETERS INCHES
MIN MAX MIN MAX
SOT-223 Mechanical Drawing
A
SOT-223 DIMENSION
B
H
F
G
E
C
D
I
J
K
DIM
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
MILLIMETERS INCHES
MIN MAX MIN MAX
TS2940 6-6 2003/12 rev. A
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