TPS73HD301, TPS73HD318, TPS73HD325

DUALOUTPUT LOW DROPOUT VOLTAGE REGULATORS

SLVS167C − SEPTEMBER 1998 − REVISED − MAY 1999

21

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

Capitalizing upon the features of the TPS73xx family (low-dropout voltage, low quiescent current, power-saving

shutdown mode, and a supply-voltage supervisor) and the power-dissipation properties of the TSSOP PowerPAD

package has enabled the integration of the TPS73HD3xx dual LDO regulator with high output current for use in DSP

and other multiple voltage applications. Figure 35 shows a typical dual-voltage DSP application.

NC

NC

1GND

1EN

1IN

1IN

NC

NC

2GND

2EN

2IN

2IN

NC

NC

1RESET

NC

NC

1FB/SENSE

1OUT

1OUT

2RESET

NC

NC

2SENSE

2OUT

2OUT

NC

NC

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

C1

1

µF

U1

TPS73HD325

C2

33

µF

3.3 V

GND

R1

100 k

Ω

R2

100 k

Ω

5 V

PG

D3

DL5817

D1

D2

2.5 V

C3

33

µF

CVdd

(Core

Supply)

DVdd

(I/O

Supply)

GND

VC549

DSP

+

RESET to DSP

C0

1

µF

Figure 33. Dual-Voltage DSP Application

DSP power requirements include very high transient currents that must be considered in the initial design. This design

uses higher-valued output capacitors to handle the large transient currents. Details of this type of design are shown

in the application report, Designing Power Supplies for TMS320VC549 DSP Systems.

minimum load requirements

The TPS73HD3xx is stable even at zero load; no minimum load is required for operation.