Datasheet
TPS767D301-Q1, TPS767D318-Q1, TPS767D325-Q1
DUAL-OUTPUT LOW-DROPOUT VOLTAGE REGULATORS
SGLS231A − FEBRUARY 2004 − JUNE 2008
15
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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 kΩ
R2
100 kΩ
5 V
PG
D3
DL5817
D1
D2
2.5 V
DL4148
C3
33 μF
CV
DD
(Core
Supply)
DV
DD
(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
load current through the regulator (I
B
= I
C
/β). Close examination of the data sheets reveals that these devices
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.