TS2940
1A 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
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 low drop output voltage (Typ. 60mV at light load and 600mV at
800mA). 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=800mA
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.
Package
Packing
TS2940CZxx C0
TO-220
50pcs / Tube
TS2940CMxx RN
TO-263
800pcs / 13” Reel
TS2940CPxx RO
TO-252
2.5Kpcs / 13” Reel
TS2940CWxx RP
SOT-223
2.5Kpcs / 13” Reel
Note: Where xx denotes voltage option, available are
50=
5.0V
33=
3.3V
25=
2.5V
18=
1.8V
Contact factory for additional voltage options.
Absolute Maximum Rating
(Note 1)
Parameter
Input Supply Voltage (Note 2)
Input Supply Voltage
Power Dissipation (Note 3)
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: A07
TS2940
1A Ultra Low Dropout Voltage Regulator
Electrical Characteristics
( V
IN
=V
OUT
+1V, I
L
=5mA, C
O
=22uF, T
A
=25
o
C
, unless otherwise noted)
Parameter
Input Supply Voltage
Output Voltage
Output Voltage Temperature
Coefficient
Line Regulation
Load Regulation
Dropout Voltage (Note 4)
Vo+2V
≤
V
IN
≤
26V
5mA
≤
I
L
≤
800mA
I
L
=100mA
I
L
=500mA
I
L
=800mA
Quiescent Current (Note 5)
Short Circuit Current (Note 6)
Output Noise,
10Hz to 100KHz, I
L
=10mA
I
L
=5mA
I
L
=800mA
V
OUT
=0
C
L
=2.2uF
C
L
=3.3uF
C
L
=33uF
5mA
≤
I
L
≤
800mA,
Vo+5V
≤
V
IN
≤
26V
Conditions
Min
--
0.970|Vo|
--
--
--
--
--
--
--
--
--
--
--
--
Typ
--
5.0 / 3.3
50
0.05
0.2
100
300
600
10
30
--
500
350
120
Max
26
1.030|Vo|
150
0.5
1.0
200
500
800
15
45
1.5
--
--
--
uVrms
mV
mA
A
Unit
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
Unit
o
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 1A at the maximum
specified temperature.
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Version: A07
TS2940
1A Ultra Low Dropout Voltage Regulator
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 22uF 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.
3/10
Version: A07
TS2940
1A 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) * 1A + 3.3V * 11mA
= 800mW + 36mW
= 836mW
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
≥60
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: A07
TS2940
1A 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: A07
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