Datasheet

MAX1533A/MAX1537A
High-Efficiency, 5x Output, Main Power-Supply
Controllers for Notebook Computers
16 ______________________________________________________________________________________
COMPONENT 5A/300kHz 5A/500kHz
Input Voltage V
IN
= 7V to 24V V
IN
= 7V to 24V
C
IN_
, Input Capacitor
(2) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
(2) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
C
OUT5
, Output Capacitor
150µF, 6.3V, 40mΩ, low-ESR capacitor
Sanyo 6TPB150ML
150µF, 6.3V, 40mΩ, low-ESR capacitor
Sanyo 6TPB150ML
C
OUT3
, Output Capacitor
220µF, 4V, 40mΩ, low-ESR capacitor
Sanyo 4TPB220ML
220µF, 4V, 40mΩ, low-ESR capacitor
Sanyo 4TPB220ML
N
H_
High-Side MOSFET
Fairchild Semiconductor FDS6612A
International Rectifier IRF7807V
Fairchild Semiconductor FDS6612A
International Rectifier IRF7807V
N
L_
Low-Side MOSFET
Fairchild Semiconductor FDS6670S
International Rectifier IRF7807VD1
Fairchild Semiconductor FDS6670S
International Rectifier IRF7807VD1
D
L_
Schottky Rectifier
(if needed)
2A, 30V, 0.45V
f
Nihon EC21QS03L
2A, 30V, 0.45V
f
Nihon EC21QS03L
Inductor/Transformer
T1 = 6.8µH, 1:2 turns Sumida 4749-T132
L1 = 5.8µH, 8.6A Sumida CDRH127-5R8NC
3.9µH
Sumida CDRH124-3R9NC
R
CS
10mΩ ±1%, 0.5W resistor
IRC LR2010-01-R010F or
Dale WSL-2010-R010F
10mΩ ±1%, 0.5W resistor
IRC LR2010-01-R010F or
Dale WSL-2010-R010F
SUPPLIER WEBSITE
AVX www.avx.com
Central Semiconductor www.centralsemi.com
Coilcraft www.coilcraft.com
Coiltronics www.coiltronics.com
Fairchild Semiconductor www.fairchildsemi.com
International Rectifier www.irf.com
Kemet www.kemet.com
Detailed Description
The MAX1533A/MAX1537A standard application circuit
(Figure 1) generates the 5V/5A and 3.3V/5A typical of the
main supplies in a notebook computer. The input supply
range is 7V to 24V. See Table 1 for component selections
and Table 2 for component manufacturers.
The MAX1533A/MAX1537A contain two interleaved
fixed-frequency step-down controllers designed for low-
voltage power supplies. The optimal interleaved archi-
tecture guarantees out-of-phase operation, reducing the
input capacitor ripple. Two internal LDOs generate
the keep-alive 5V and 3.3V power. The MAX1537A has
an auxiliary LDO that can be configured to the preset
12V output or an adjustable output.
Fixed Linear Regulators (LDO5 and LDO3)
Two internal linear regulators produce preset 5V (LDO5)
and 3.3V (LDO3) low-power outputs. LDO5 powers
LDO3, the gate drivers for the external MOSFETs, and
provides the bias supply (V
CC
) required for the SMPS
analog control, reference, and logic blocks. LDO5
supplies at least 100mA for external and internal loads,
including the MOSFET gate drive, which typically varies
from 5mA to 50mA, depending on the switching frequen-
cy and external MOSFETs selected. LDO3 also supplies
at least 100mA for external loads. Bypass LDO5 and
LDO3 with a 2.2µF or greater output capacitor, using an
additional 1.0µF per 20mA of internal and external load.
Table 1. Component Selection for Standard Applications
Table 2. Component Suppliers
SUPPLIER WEBSITE
Panasonic www.panasonic.com/industrial
Sanyo www.semiconductor-sanyo.com
Sumida www.sumida.com
Taiyo Yuden www.t-yuden.com
TDK www.component.tdk.com
TOKO www.tokoam.com
Vishay (Dale, Siliconix) www.vishay.com