TS2937

1-1

2003/12 rev. B

TS2937

500mA Ultra Low Dropout Fixed Positive Voltage Regulator

Pin assignment:

1. Input
2. Ground

Output

Low Dropout Voltage 0.6V max.

General Description

he TS2937 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 500mA). 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=500mA

Output current up to 500mA

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)

Package

TS2937CZ

TO-220

TS2937CM

TO-263

TS2937CP

TO-252

TS2937CW

-20 ~ +85

SOT-223

Note: Where

denotes voltage option, available are

12V, 10V, 8V, 5V, 3.3V and 2.5V. 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)

Power Dissipation (Note 3)

Internally Limited

Operating Junction Temperature Range

-25 ~ +125

Storage Temperature Range

STG

-65 ~ +150

Lead Soldering Temperature (260

TO-220 / TO-263 Package

TO-252 / SOT-223 Package

5
4

TO-263

TS2937

2-2

2003/12 rev. B

Electrical Characteristics

Vin = Vout + 1V, 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

500mA,

Vo+1V

Vin 26V

0.970|Vo|

Vout

1.030|Vo| V

Input Supply Voltage

Output Voltage Temperature

Coefficient

150

ppm/

Line Regulation

Vo+1V

Vin 26V

0.05

0.5

Load Regulation

5mA

500mA

0.2

1.0

Dropout Voltage (Note 4)

=100mA

=300mA

=500mA

100

300

500

200

400

600

Quiescent Current (Note 5)

=100uA

=300mA

=500mA

100

Short Circuit Current (Note 6)

Vout=0

1.3

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 500mA at the maximum

specified temperature.

TS2937

3-3

2003/12 rev. B

Application Information

The TS2937 series is a high performance with low dropout
voltage regulator suitable for moderate to high current and
voltage regulator application. Its 600mV(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 TS2937 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 TS2937 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 TS2937 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) * 0.5A + 3.3V * 11mA

= 400mW + 36mW

= 436mW

Remark: I

is output load current,

is ground current.

Vin is input voltage

Vout is output voltage

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

TS2937

4-4

2003/12 rev. B

Application Information (continued)

(max) 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.T

(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,

, can now be found:

= 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

falls below

these limits, a heatsink is required.

TS2937

5-5

2003/12 rev. B

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

TS2937

6-6

2003/12 rev. B

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: TS2937CZ5.0