EP53A8LQI Datasheet, PDF (12/14 Pages) Enpirion, Inc. – 1000mA Synchronous Buck Regulator with Integrated Inductor

EP53A8HQI High VID Range
Programming
The EP53A8HQI V_OUT settings are optimized
for higher nominal voltages such as those
required to power IO, RF, or IC memory. The
preset voltages range from 1.8V to 3.3V.
There are eight (8) preset output voltage
settings. The EP53A8HQI does not have an
external divider option. As with the
EP53A8LQI, the VID pin settings can be
changed while the device is enabled.
Table 2 shows the VS0-VS2 pin logic states for
the EP53A8HQI and the associated output
voltage levels. A logic “1” indicates a
connection to AVIN or to a “high” logic voltage
level. A logic “0” indicates a connection to
AGND or to a “low” logic voltage level. These
pins can be either hardwired to AVIN or AGND
or alternatively can be driven by standard logic
levels. Logic levels are defined in the electrical
characteristics table. Any level between the
logic high and logic low is indeterminate.
These pins must not be left floating.
Table 2: EP53A8HQI VID Voltage Select Settings
VS2
VS1
VS0
VOUT
0
0
0
3.3
0
0
1
3.0
0
1
0
2.9
0
1
1
2.6
1
0
0
2.5
1
0
1
2.2
1
1
0
2.1
1
1
1
1.8
Input Filter Capacitor
The input filter capacitor requirement is a
4.7µF 0603 low ESR MLCC capacitor. The
EP53A8LQI/EP53A8HQI
input capacitor must use a X5R or X7R or
equivalent dielectric formulation. Y5V or
equivalent dielectric formulations lose
capacitance with frequency, bias, and with
temperature, and are not suitable for switch-
mode DC-DC converter input filter applications.
Output Filter Capacitor
The output filter capacitor requirement is a
minimum of 10µF 0805 MLCC. Ripple
performance can be improved by using 2x10µF
0603 or 2x10µF 0805 MLCC capacitors.
The maximum output filter capacitance next to
the output pins of the device is 60µF low ESR
MLCC capacitance. V_OUT has to be sensed at
the last output filter capacitor next to the
EP53A8xQI.
Additional bulk capacitance for decoupling and
bypass can be placed at the load as long as
there is sufficient separation between the V_OUT
Sense point and the bulk capacitance. The
separation provides an inductance that isolates
the control loop from the bulk capacitance.
Excess total capacitance on the output (Output
Filter + Bulk) can cause an over-current
condition at startup. Refer to the section on
Soft-Start for the maximum total capacitance
on the output.
The output capacitor must use a X5R or X7R or
equivalent dielectric formulation. Y5V or
equivalent dielectric formulations lose
capacitance with frequency, bias, and
temperature and are not suitable for switch-mode
DC-DC converter output filter applications.
©Enpirion 2009 all rights reserved, E&OE
03651
12
12/16/2009
www.enpirion.com
Rev:B