MAX1882EUG Maxim Integrated, MAX1882EUG Datasheet - Page 33

• Manufacturer Part Number: MAX1882EUG
• Description: LCD Drivers Quad-Output TFT LCD DC-DC Converter with Buffer
• Manufacturer: Maxim Integrated

Specifications of MAX1882EUG

• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Package / Case: TSSOP-24
• Mounting Style: SMD/SMT

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).
Maxim Integrated
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
NEG
= 3.3V TO 5V
SUPB
NEGATIVE
= -12V
/2
Applications Information
INPUT
1.0µF
0.22µF
C3
C
4.7µF
0.1µF
REF
C
Low-Profile Components
C1
IN
C
1.0µF
BUF
470pF
100kΩ
C
100kΩ
475kΩ
R
INTG
R10
R5
RDY
Desktop Monitors
49.9kΩ
30kΩ
R6
R9
0.1µF
C2
BUFOUT
MAX1778/MAX1880–MAX1885
BUF-
DRVN
FBN
REF
FLTSET
IN
SHDN
RDY
INTG
PGND
Quad-Output TFT LCD DC/DC
MAX1778
6.8µH
L1
LDOOUT
SUPB
SUPN
SUPP
DRVP
TGND
SUPL
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