en5322 Enpirion, en5322 Datasheet - Page 11

• Manufacturer Part Number: en5322
• Description: 2 A Voltage Mode Synchronous Buck Pwm Dc-dc Converter With Integrated Inductor
• Manufacturer: Enpirion

March 2008
Figure 5. Typical Application Circuit with External Resistor Divider.
(NOTE: Enable can be separated from PVIN if the application requires it)
Application Information
Setting the Output Voltage
To provide the highest degree of flexibility in
choosing output voltage, the EN5322QI uses a
3 pin VID (Voltage ID) output voltage select
arrangement. This allows the designer to
choose one of seven preset voltages, or to use
an external voltage divider. Figure 4 shows a
typical application circuit with VID codes.
Internally, the output of the VID multiplexer
sets the value for the voltage reference DAC,
which in turn is connected to the non-inverting
input of the error amplifier. This allows the use
of a single feedback divider with constant loop
gain and optimum compensation, independent
of the output voltage selected.
Table 1 shows the various VS0-VS2 pin logic
states and the associated output voltage
levels. A logic “1” indicates a connection to V
or to a “high” logic voltage level. A logic “0”
indicates a connection to ground or to a “low”
logic voltage level. These pins can be either
hardwired to V
driven by standard logic levels. Logic low is
defined as V
as V
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HIGH
≥ 1.4V. Any level between these two
LOW
IN
or GND or alternatively can be
≤ 0.4V. Logic high is defined
IN
11
values is indeterminate. These pins must not
be left floating.
Table 1. VID voltage select settings.
External Voltage Divider
As described above, the external voltage
divider option is chosen by connecting the
VS0, VS1, and VS2 pins to VIN or logic “high”.
The EN5322QI uses a separate feedback pin,
V
must be connected to V
Figure 5.
VS2
0
0
0
0
1
1
1
1
FB
, when using the external divider. VSENSE
VS1
0
0
1
1
0
0
1
1
VS0
0
1
0
1
0
1
0
1
OUT
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as indicated in
V
Selectable
EN5322QI
OUT
1.25V
3.3V
2.5V
1.8V
1.5V
1.2V
0.8V
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