MAX1880EUG Maxim Integrated Products, MAX1880EUG Datasheet - Page 33

• Manufacturer Part Number: MAX1880EUG
• Description: DC/DC Switching Converters
• Manufacturer: Maxim Integrated Products

Specifications of MAX1880EUG

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Notebook applications generally require low-profile
components, potentially limiting the circuit’s perfor-
mance. For example, low-profile inductors typically
have lower saturation ratings and more series resis-
tance, limiting output current and efficiency. Low-profile
capacitors have lower voltage ratings for a given
capacitance value, so 3.3µF low-profile capacitors with
voltage ratings greater than 10V were not available at
the time of publication.
Monitor applications do not have the same component
height restrictions associated with laptops, allowing
more flexibility in component selection (Figure 8).
Figure 9. Input Voltage Above and Below the Output Voltage
V
BUFOUT
BUFFER OUTPUT
V
BATT
V
= V
IN
TO LOGIC
POWER INPUT
V
= 10V TO 15V
= 3.3V TO 5V
SUPB
NEG
NEGATIVE
= -12V
Applications Information
/2
INPUT
______________________________________________________________________________________
1.0μF
0.22μF
C3
C
4.7μF
0.1μF
REF
Low-Profile Components
C
C1
IN
C
1.0μF
BUF
470pF
100kΩ
C
100kΩ
475kΩ
INTG
R
R10
R5
RDY
Desktop Monitors
49.9kΩ
30kΩ
R6
R9
0.1μF
C2
BUFOUT
REF
FLTSET
BUF-
DRVN
FBN
IN
SHDN
RDY
INTG
PGND
Quad-Output TFT LCD DC-DC
MAX1778
6.8μH
L1
LDOOUT
SUPN
TGND
SUPL
SUPB
SUPP
DRVP
BUF+
GND
FBP
FBL
LX
FB
Larger output capacitors with higher voltage ratings
allow configurations with output voltages above 10V.
Additionally, physically larger inductors with less series
resistance and higher saturation ratings provide more
output current and higher efficiency.
Combining the step-up converter and linear regulator
as shown in Figure 9 provides output voltage regulation
above and below the input voltage. Supplied by the
step-up converter, the linear regulator output provides
a constant output voltage (V
age exceeds the main step-up converter’s nominal out-
put voltage, the controller stops switching but the linear
regulator maintains the output voltage. When the input
voltage drops below the output voltage, the step-up
Converters with Buffer
0.1μF
C4
470kΩ
49.9kΩ
511kΩ
R7
0.1μF
C6
R4
49.9kΩ
R1
R2
49.9kΩ
909kΩ
R3
R8
0.1μF
C7
Below the Output Voltage
C
3.3μF
Input Voltage Above and
C
(3) 3.3μF
LDOOUT
OUT
6.8kΩ
R9
LDO
C5
1.0μF
). When the input volt-
POSITIVE
V
POS
Q1
= 24V
C
(2) 3.3μF
LDO
LDO
V
LDO
= 13V
33