TS2937
500mA Ultra Low Dropout Voltage Regulator
TO-220
TO-263
2
(D PAK)
TO-252
(DPAK)
SOT-223
Pin Definition:
1. Input
2. Ground
3. Output
General Description
TS2937 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 (200uA Typ.) and very low drop output voltage (Typ. 60mV at light load and 600mV at 500mA). This
includes a tight initial tolerance of 2%, extremely good line regulation of 0.05% typ., and very low output
temperature coefficient.
Features
●
●
●
●
●
●
●
Dropout voltage typically 0.6V @ Io=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
Ordering Information
Part No.
Package
Packing
TS2937CZxx C0
TO-220
50pcs / Tube
TS2937CMxx RN
TO-263
800pcs / 13” Reel
TS2937CPxx RO
TO-252
2.5Kpcs / 13” Reel
TS2937CWxx RP
SOT-223
2.5Kpcs / 13” Reel
Note: Where xx denotes voltage option, available are
12=
12V
50=
5V
33=
3.3V
Contact factory for additional voltage options.
Block Diagram
Absolute Maximum Rating
Parameter
Input Supply Voltage
Operation Input Supply Voltage
Power Dissipation
Operating Junction Temperature Range
Storage Temperature Range
Symbol
V
IN
V
OPR
P
D
T
J
T
STG
Limit
-18 ~ +60
26
Internally Limited
-40 ~ +125
-65 ~ +150
Unit
V
V
W
o
o
C
C
1/10
Version: D13
TS2937
500mA Ultra Low Dropout Voltage Regulator
Electrical Characteristics
( V
IN
=V
OUT
+1V, I
L
=5mA, C
O
=10uF, T
A
=25
o
C
, unless otherwise noted)
Parameter
Output Voltage
Output Voltage
Input Supply Voltage
Output Voltage Temperature Coefficient
Line Regulation
Load Regulation
Dropout Voltage (Note 4)
Vo+1V
≤
V
IN
≤
26V
5mA
≤
I
L
≤
500mA
I
L
=100mA
I
L
=300mA
I
L
=500mA
I
L
=100uA
Quiescent Current (Note 5)
Short Circuit Current (Note 6)
Output Noise,
10Hz to 100KHz, I
L
=10mA
I
L
=300mA
I
L
=500mA
V
OUT
=0
C
L
=2.2uF
C
L
=3.3uF
C
L
=33uF
5mA
≤
I
L
≤
500mA,
Vo+1V
≤
V
IN
≤
26V
Conditions
Min
0.980|Vo|
0.970|Vo|
--
--
--
--
--
--
--
--
--
--
--
--
--
--
Typ
12 / 10
5.0 / 3.3
--
50
0.05
0.2
100
400
600
200
12
25
--
500
350
120
Max
1.020|Vo|
1.030|Vo|
26
150
0.5
1.0
300
500
700
--
--
--
1.3
--
--
--
uVrms
uA
mA
mA
A
mV
Unit
V
V
V
ppm/ C
%
%
o
Thermal Performance
Condition
Thermal Resistance
Junction to Ambient
Package type
TO-220
TO-263
TO-252
Typ
60
80
150
o
Unit
C/W
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 3: 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 4: 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 5: Output current will decrease with increasing temperature, but it will be not dropped below 500mA at the
maximum specified temperature.
2/10
Version: D13
TS2937
500mA Ultra Low Dropout Voltage Regulator
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 1mA 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.
3/10
Version: D13
TS2937
500mA Ultra Low Dropout Voltage Regulator
Application Information (Continue)
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
D
must be calculated.
The below formula shows the voltages and currents for calculating the P
D
in the regulator:
IIN = IL / IG
P
D
= (V
IN
-V
OUT
) * I
L
+ (V
IN
) * I
G
Ex. P
D
= (3.3V-2.5V) * 0.5A + 3.3V * 11mA
= 400mW + 36mW
= 436mW
Remark: I
L
is output load current,
I
G
is ground current.
V
IN
is input voltage
V
OUT
is output voltage
The next parameter which must be calculated is the maximum allowable temperature rise.
TR(max) is calculated by the using to formula:
TR(max) = TJ(max) – TA(max)
Where: TJ(max) is the maximum allowable junction temperature, which is 125 C for commercial grade parts.
T
A
(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
IMPORTANT: if the maximum allowable value for is found to be
≥6
C /W for the TO-220 package,
≥80
C/W for the
o
o
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
θja
falls below these limits, a heatsink is required.
o
o
o
4/10
Version: D13
TS2937
500mA Ultra Low Dropout Voltage Regulator
Application Information (Continue)
Figure 1 – D PAK Thermal Resistance and Maximum Power
Dissipation vs. P.C.B Copper Length
2
Figure 2 – DPAK Thermal Resistance and Maximum Power
Dissipation vs. P.C.B Copper Length
Figure 3 – SOT-223 Thermal Resistance and Maximum Power
Dissipation vs. P.C.B Copper Length
5/10
Version: D13
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