TPS767D301, TPS767D318, TPS767D325

DUAL-OUTPUT LOW-DROPOUT VOLTAGE REGULATORS

SLVS209B – JULY 1999 – REVISED APRIL 2000

14

POST OFFICE BOX 655303

APPLICATION INFORMATION

The features of the TPS767D3xx family (low-dropout voltage, ultra low quiescent current, power-saving shutdown

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

have enabled the integration of the dual LDO regulator with high output current for use in DSP and other multiple

voltage applications. Figure 25 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/NC

1OUT

1OUT

2RESET

NC

NC

NC

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

TPS767D325

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 25. 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.

device operation

The TPS767D3xx features very low quiescent current, which remain virtually constant even with varying loads.

Conventional LDO regulators use a pnp pass element, the base current of which is directly proportional to the

are typically specified under near no-load conditions; actual operating currents are much higher as evidenced

by typical quiescent current versus load current curves. The TPS767D3xx uses a PMOS transistor to pass

current; because the gate of the PMOS is voltage driven, operating current is low and invariable over the full

load range. The TPS767D3xx specifications reflect actual performance under load condition.