TS2940 1-6

2003/12

rev.

TS2940

1A Ultra Low Dropout Fixed Positive Voltage Regulator

Low Dropout Voltage 0.6V (typ.)

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.

Package

TS2940CZ

TO-220

TS2940CM

-40 ~ +125

TO-263

TS2940CP

TO-252

TS2940CW

-40 ~ +85

SOT-223

Note: Where

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

-18 ~ +60

Operation Input Supply Voltage

Vin (operate)

30V

Power Dissipation (Note 3)

Internally Limited

Operating Junction Temperature Range

-40 ~ +125

Storage Temperature Range

STG

-65 ~ +150

Lead Soldering Temperature (260

TO-220 TO-263 Package

TO-252 / SOT-223Package

5
4

TO-263

Pin assignment:
1. Input
2. Ground
3. Output

TS2940 2-6

2003/12

rev.

Electrical Characteristics

Vin = Vout + 5V, I

= 5mA, C

= 10uF, Ta = 25

C, unless otherwise specified.

Parameter Conditions

Min Typ Max

Unit

Output Voltage

0.980|Vo|

1.020|Vo|

Output Voltage

5mA

1A,

Vo+5V

Vin 26V

0.970|Vo|

5.0 / 3.3

2.5 / 1.8

1.030|Vo| V

Input Supply Voltage

Output Voltage Temperature

Coefficient

150

ppm/

Line Regulation

Vo+2V

Vin 26V

0.05

0.5

Load Regulation

5mA

0.2

1.0

Dropout Voltage (Note 4)

=100mA

=500mA

=800mA

100

300

600

200

500

800

Quiescent Current (Note 5)

=5mA

=800mA

Short Circuit Current (Note 6)

Vout=0

1.5

Output Noise,

10Hz

to 100KHz, I

=10mA

=2.2uF

=3.3uF

=33uF

500

350

120

uVrms

Thermal Performance

Condition Package

type

Typ Unit

TO-220 60

TO-263 80

TO-252 150

Thermal Resistance

Junction to Ambient

SOT-223 170

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, ja, 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 ja 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 3-6

2003/12

rev.

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

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.

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, P

must be calculated.

The below formula shows the voltages and currents
for calculating the P

in the regulator:

Iin = I

/ I

= (Vin-Vout) * I

+ (Vin) * I

Ex. P

= (3.3V-2.5V) * 1A + 3.3V * 11mA

= 800mW + 36mW

= 836mW

Remark: I

is output load current,

is ground current.

Vin is input voltage

Vout is output voltage

TS2940 4-6

2003/12

rev.

Application Information (continued)

The next parameter which must be calculated is the
maximum allowable temperature rise, T

(max). this is

calculated by the using to formula:

(max) = T

(max) � T

(max)

Where: T

(max) is the maximum allowable junction

temperature, which is 125

C for commercial

grade parts.

(max) is the maximum ambient temperature

which will be encountered in the application.

Using the calculated values for T

(max) and P

, the

maximum allowable value for the junction to ambient
thermal resistance, ja, can now be found:
ja = T

(max) / P

IMPORTANT: if the maximum allowable value for is
found to be 60

C/W for the TO-220 package, 80

C/W

for the TO-263 package, 150

C/W for the TO-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 ja falls below these limits, a
heatsink is required.

TS2940 5-6

2003/12

rev.

TO-220 Mechanical Drawing

TO-220 DIMENSION

MILLIMETERS INCHES

DIM

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

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-263 Mechanical Drawing

TO-263 DIMENSION

MILLIMETERS INCHES

DIM

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

TS2940 6-6

2003/12

rev.

TO-252 Mechanical Drawing

TO-252 DIMENSION

MILLIMETERS INCHES

DIM

MIN 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

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

SOT-223 Mechanical Drawing

SOT-223 DIMENSION

MILLIMETERS INCHES

DIM

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

Электронный компонент: TS2940CZ3.3