MAX1631EAI+T Maxim Integrated Products, MAX1631EAI+T Datasheet - Page 8

• Manufacturer Part Number: MAX1631EAI+T
• Description: IC PS CTRLR FOR NOTEBOOKS 28SSOP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX1631EAI+T

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 3.3V, 5V, Adj
• Current - Output: 4A
• Frequency - Switching: 200kHz, 300kHz
• Voltage - Input: 4.2 ~ 30 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Power - Output: 762mW
• Output Voltage: 2.5 V to 5.5 V, 3.3 V, 5 V
• Input Voltage: 4.2 V to 30 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
The basic MAX1631/MAX1634 dual-output 3.3V/5V
buck converter (Figure 1) is easily adapted to meet a
wide range of applications with inputs up to 28V by
substituting components from Table 1. These circuits
represent a good set of tradeoffs between cost, size,
and efficiency, while staying within the worst-case
specification limits for stress-related parameters, such
as capacitor ripple current. Don’t change the frequency
Figure 1. Standard 3.3V/5V Application Circuit (MAX1631/MAX1634)
_______Standard Application Circuit
8
C1
+5V OUTPUT
_______________________________________________________________________________________
*
3.3V ON/OFF
5V ON/OFF
R1
INPUT
C3
L1
0.1μF
Q1
Q2
10Ω
0.1μF
4.7μF
0.1μF
GND
V+ SHDN
BST5
DH5
LX5
DL5
CSH5
CSL5
FB5
TIME/ON5
RUN/ON3
PGND
REF
ON/OFF
MAX1631
MAX1634
1μF
SECFB
of these circuits without first recalculating component
values (particularly inductance value at maximum bat-
tery voltage). Adding a Schottky rectifier across each
synchronous rectifier improves the efficiency of these
circuits by approximately 1%, but this rectifier is other-
wise not needed because the MOSFETs required for
these circuits typically incorporate a high-speed silicon
diode from drain to source. Use a Schottky rectifier
rated at a DC current equal to at least one-third of the
load current.
RESET
STEER
SYNC
CSH3
BST3
CSL3
SKIP
SEQ
DH3
LX3
DL3
FB3
VL
*1A SCHOTTKY DIODE REQUIRED
FOR THE MAX1631 (SEE OUTPUT
OVERVOLTAGE PROTECTION SECTION).
0.1μF
0.1μF
RESET OUTPUT
+2.5V ALWAYS ON
Q4
Q3
0.1μF
4.7μF
+5V ALWAYS ON
L2
R2
+3.3V OUTPUT
*
C2