MIC28510 12V EV Micrel, MIC28510 12V EV Datasheet - Page 2

• Manufacturer Part Number: MIC28510 12V EV
• Description: Power Management IC Development Tools 75V/4A DC-DC Buck Regulator with HSC - Evaluation Board
• Manufacturer: Micrel
• Type: DC/DC Converters, Regulators & Controllersr

Specifications of MIC28510 12V EV

• Product: Evaluation Boards
• Tool Is For Evaluation Of: MIC28510
• Input Voltage: 4.5 V to 75 V
• Output Voltage: 12 V
• Description/function: Evaluation Board
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Output Current: 4 A
• For Use With: MIC28510

March 2012
Features
Feedback Resistors
The output voltage on the
board, which is preset to 3.3V, is determined by the
feedback divider, shown in Equation 1:
where V
which corresponds
2.5V, 3.3V, or 5V. Leaving the R
0.8V output voltage. All
above can be set by modifying R
according to Equation 2:
Note that the output voltage should not be
exceed
output capacitors.
If higher than 5V output is desired, it is reco
to use the designs s
output evaluation board schematic, where th
capacitors, L1, R3, and R17 are optimize
output.
SW N
Test point J11 (V
switching
waveforms for the converter.
Current Limit
The MIC28510 has internal FETs, and the curre
is implemented by sensing the R
The MIC28510 has a fixed current limi
(typical).
Loop Gain M
The resistor, R13, is placed in series with the reg
feedback path. The control loop gain can be
measured by connecting an impedance analyzer
across the resistor and selecting the resistor value in
between 20Ω to 50Ω.
Setting the Switching Frequency
The
synchronous buck regulator featuring a unique
digitally
architecture.
ode
MIC28510
R
V
5V due to the 6.3V voltage rating o
REF
OUT
BOTTOM
modified
waveform,
= 0.8V, and R
easurement
=
V
REF
=
SW
to 0.9V, 1.0V, 1.2V, 1.5V, 1.8V,
V
is
) is placed for monitori
hown in the MIC28510 12V/4A
×
R4 ×
OUT
⎛
⎜
⎜
⎝
adaptive
one
1
+
an
−
V
R
other voltages not listed
BOTTOM
REF
V
BOTTOM
REF
of
R4
MIC28510 evaluation
adjustable-frequency,
DS-ON
BOTTOM
the
is one o
on-time
⎞
⎟
⎟
⎠
of bott
mos
BOTTOM
open gives a
d for 12V
t of
f R5-R12,
mmended
t
om FET.
e output
ng the
control
nt limit
critical
set to
n the
ulator
v
Eq. 1
Eq. 2
6.5A
alu
e
2
The switching frequency can
100kHz and 500kHz by changi
connected network consisting of R18 and R19 from
PVIN to PGND.
Equation 3 illustrates the estimated
where f
and R19 being open, f
For more precise setting, it is recommended to use
Figure 2:
The evaluation board design is optimized for a
switching frequency of 250kHz. If the switching
frequency is programmed to either lower end or higher
end, the design needs optimization.
Figure 1. Switching Frequency Adjustment
O
Figure 2. Switching Frequency vs. R19
f
SW_ADJ
= Switching Frequency when R18 is 100k
=
[e-mail]
f
O
×
R18
O
should be typically 450kHz.
R19
+
R19
ng the resistor divider
be adjusted between
switching frequency:
or [phone]
M9999-030712
Eq. 3