TS39105 Taiwan Semiconductor, TS39105 Datasheet - Page 7

• Manufacturer Part Number: TS39105
• Description: (TS39100 - TS39105) 1A Ultra Low Dropout Voltage Regulator
• Manufacturer: Taiwan Semiconductor

Application Information (Continue)
Transient Response and 3.3V to 2.5V or 2.5V to 1.8V Conversion
TS39100/1/2/3/4/5 has excellent transient response to variations in input voltage and load current. The device have
been designed to respond quickly to load current variations and input voltage variations. Large output capacitors are
not required to obtain this performance. A standard 10uF output capacitor, preferably tantalum, is all that is required.
Larger values help to improve performance even further. By virtue of its low dropout voltage, this device does not
saturate into dropout as readily as similar NPN base designs. When converting from 3.3V to 2.5V or 2.5V to 1.8V, the
NPN based regulators are already operating in dropout, with typical dropout requirements of 1.2V or greater,. To
convert down to 2.5V or 1.8V without operating in dropout, NPN based regulators require an input voltage of 3.7V at
the very least. The TS3910x regulator will provide excellent performance with an input as low as 3.0V or 2.5V
respectively. This gives the PNP based regulators a distinct advantage over older, NPN based linear regulators.
Power Dissipation
From under curves, the minimum area of copper necessary for the par to operate safely can be determined. The
maximum allowable temperature rise must be calculated to determine operation along which curve.
Copper area lay out information
Determine the power dissipation requirements for the design along with the maximum ambient temperature at which
the device will be operated. Refer to power dissipation with copper area curve, which shows safe operating curves for
three different ambient temperatures with 25
be determined by knowing the maximum power dissipation required.
P
If we used a 5.0V output device and a 6V input at an output current of 350mA, then the power dissipation is as follows:
P
P
P
If the maximum ambient temperature is 85
the required area of copper is 80mm
D
D
D
D
= (V
= (6.0V- 5.0V) * 350mA + 5V * 4mA
= 350mW + 20mW
= 370mW
IN
- V
OUT
) * I
OUT
+ V
IN
* I
GND
2
.
o
C and the power dissipation is as above 375mW, the curve is shows that
o
C, 50
o
C, 85
1A Ultra Low Dropout Voltage Regulator
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o
C. From these curves, the minimum amount of copper can
TS39100/1/2/3/4/5
with Multi-Function
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Version: B07