IOUT = 10 mA

IOUT = 100 mA

60

50

30

20

10

100

1k

10k

70

90

100

100k

1M

10M

40

80

f – Frequency – Hz

3

t – Time –

s

m

0

60

40

20

80 100

140

120

160 180 200

1

2

0

0

2

CBYPASS = 0.001 F

m

CBYPASS = 0.01 F

m

1

3

CBYPASS = 0.0047 F

m

17

TPS791

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Copyright © 2001–2018, Texas Instruments Incorporated

Typical Application (continued)

8.2.1 Design Requirements

Table 2 shows the parameters used for this design example.

Table 2. Design Parameters

PARAMETER

DESIGN REQUIREMENT

Input voltage

4.3 V to 3.5 V (Lithium Ion battery)

Output voltage

3.3 V

DC output current

10 mA

Peak output current

100 mA

Maximum ambient temperature

60°C

8.2.2 Detailed Design Procedure

Select the desired output voltage option. An input capacitor of 0.1 µF is used because the battery is connected to

the input through a via and a short 10-mil (0.01-in) trace. An output capacitor of 1 mF is used in this design

example. A smaller size output capacitor can be used up to a minimum of 1 µF to stabilize the internal control

loop.

8.2.3 Application Curves

Figure 36. TPS79133 Ripple Rejection vs Frequency

Figure 37. TPS79133 Output Voltage, Enable Voltage vs

Time (Start-Up)

8.3 Do's and Don'ts

Do place at least one, low-ESR, 1-µF capacitor as close as possible between the OUT pin of the regulator and

the GND pin.

Do place at least one, low-ESR, 0.1-µF capacitor as close as possible between the IN pin of the regulator and

the GND pin.

Do provide adequate thermal paths away from the device.

Do not place the input or output capacitor more than 10 mm away from the regulator.

Do not exceed the absolute maximum ratings.

Do not float the Enable (EN) pin.

Do not resistively or inductively load the BYPASS pin.

Do not let the output voltage get more than 0.3 V above the input voltage.