MAX1927REUB Maxim Integrated Products, MAX1927REUB Datasheet - Page 10

• Manufacturer Part Number: MAX1927REUB
• Description: DC/DC Switching Converters 800mA PWM Step-Down DC/DC Converter
• Manufacturer: Maxim Integrated Products

Resistors R1 and R2 are external to the MAX1927 (see
the Setting the Output Voltage section). I
maximum output current, R
250µS for the MAX1927. See the Electrical Characteristics
table for MAX1928 g
C
3) Calculate the equivalent load impedance, R
4) Calculate the compensation resistance (R
Low-Output-Voltage, 800mA, PWM Step-Down
DC-DC Converters
Figure 4. Applications Circuit for the MAX1927
10
Figure 3. Applications Circuit for the MAX1928
C
value that gives an acceptable bandwidth.
For the MAX1928:
______________________________________________________________________________________
C
C
I
OUT MAX
V
OUT
(
R
L
m
)
values. Select the closest standard
I
OUT MAX
1200pF
680pF
V
OUT
R
C
C
(
C
CS
C
1
CS
)
= 0.48V/A, and g
10 F
10 F
15k
18k
g
C1
2.6V TO 5.5V
R
C1
2.6V TO 5.5V
R
C
m
C
V
V
IN
IN
0.1 F
0.1 F
OUT(MAX)
C3
C3
2
C
22pF
1
C
22pF
f
f
f
C
C
) to can-
L
, by:
BATT
SHDN
COMP
REF
BATT
SHDN
COMP
REF
is the
m
=
MAX1928-18
MAX1927R
GND
GND
Solving for R
5) Calculate the high-frequency compensation pole to
PGND
cel out the dominant pole created by the output
load and the output capacitance:
cancel the zero created by the output capacitor’s ESR:
PGND
PWM
PWM
POK
POK
LX
FB
LX
FB
CDRH4D18
CDRH4D18
4.7 H
4.7 H
2
L1
C
L1
2
gives:
R
ESR
R
R
L
1
C
1
R1
16.5k
1%
R2
49.9k
1%
1.8V AT 800mA
C
C
V
R
OUT
OUT
OUT
L
1V AT 800mA
C2
10 F
C
V
C
OUT
C
OUT
2
2
C2
10 F
R
1
R
C
1
C
C
C
C
f