Datasheet

R
EXT =
1 M:
LOW
POWER
MODE
R
EXT =
100 k:
MID
POWER
MODE
R
EXT =
0:
HIGH
POWER
MODE
+
-
-
+
VOUT
LPV531
I
SEL
IN
V
INT
= 110 mV
R
INT
= 11 k:
6
V
+
2
V
-
1
OUT
5
I
SEL
R
EXT
4
3
IN
-
IN
+
+
-
LPV531
SNOSAK5B –MARCH 2006–REVISED MARCH 2013 www.ti.com
Figure 36. Single Power Mode
Switched Discrete Power Modes
In this typical application, the LPV531 can operate at two (or more) power modes in order to fulfill the demands
of the design. One of the modes is used to save power. It is a low power mode which is set by using a large
resistor. The others are the higher power modes which are set by one or more smaller resistors. The larger
resistor that sets the low power mode can be permanently connected while the smaller resistor(s) can be
switched in parallel to set the high power mode(s). This configuration allows the designer to get the required
performance from the LPV531 when needed.
Figure 37. Power Modes Set by Resistors and Switches
The switches shown in Figure 37 can be easily implemented with an open drain I/O port of an ASIC or any other
simple pull down switch.
DAC Controlled Power Modes
For voltage controlled filter applications, where control of the gain bandwidth is essential, a DAC and a resistive
voltage divider can be used. In this application the current drawn from the I
SEL
pin is controlled by the DAC. The
DAC’s total output range is divided to match the V
−
to V
INT
voltage which has the range of 0-110 mV.
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