Part Number

MAX8554

Description

4.5V to 28V Input / Synchronous PWM Buck Controllers

Manufacture

Maxim

Total Page 24 Pages
PDF Download
Download MAX8554 Datasheet PDF


Features Datasheet pdf 19-3017; Rev 0; 10/03 4.5V to 28V Input , Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Appli cations General Description The MAX8553 is a 4.5V to 28V input-voltage, synchr onous step-down controller that provide s a complete power-management solution for DDR memory. The MAX8553 generates 1 /2 VREFIN voltage for VTT and VTTR. The VTT and VTTR tracking voltages are mai ntained within 1% of 1/2 VREFIN. The MA X8554 is a 4.5V to 28V input voltage, n ontracking step-down controller with a low 0.6V feedback threshold voltage. Th e MAX8553/ MAX8554 use Maxim’s propri etary Quick-PWM™ architecture for fas t transient response and operate with s electable pseudo-fixed frequencies. Both.
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MAX8554 Datasheet
19-3017; Rev 1; 5/05
4.5V to 28V Input, Synchronous PWM Buck Controllers
for DDR Termination and Point-of-Load Applications
General Description
The MAX8553 is a 4.5V to 28V input-voltage, synchro-
nous step-down controller that provides a complete
power-management solution for DDR memory. The
MAX8553 generates 1/2 VREFIN voltage for VTT and
VTTR. The VTT and VTTR tracking voltages are main-
tained within 1% of 1/2 VREFIN. The MAX8554 is a 4.5V to
28V input voltage, nontracking step-down controller with
a low 0.6V feedback threshold voltage. The MAX8553/
MAX8554 use Maxim’s proprietary Quick-PWM™ archi-
tecture for fast transient response and operate with
selectable pseudo-fixed frequencies. Both controllers
can operate without an external bias supply.
The controllers operate in synchronous-rectification mode
to ensure balanced current sourcing and sinking capabili-
ty of up to 25A. The MAX8553/MAX8554 also provide up
to 95% efficiency, making them ideal for server and point-
of-load applications. Additionally, a low 5µA shutdown
current allows for longer battery life in notebook applica-
tions. Lossless current monitoring is achieved by monitor-
ing the low-side MOSFET’s drain-to-source voltage. The
MAX8553/MAX8554 have an adjustable foldback current
limit to withstand a continuous output overload and short
circuit. Digital soft-start provides control of inrush current
during power-up. Overvoltage protection shuts the con-
verter down and discharges the output capacitor. The
MAX8553/MAX8554 come in space-saving 16-pin QSOP
packages.
Applications
Wide-Input Power Supplies
Servers and Storage Applications
ASIC and CPU Core Voltages
Notebook and LCD-PC Power Supplies
DDR I and DDR II Memory Power Supplies
AGTL Bus Termination Supplies
PART
MAX8553EEE
MAX8554EEE
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 QSOP
16 QSOP
Features
Up to 25A Output-Current Capability
Quick-PWM Control for Fast Loop Response
Up to 95% Efficiency
4.5V to 28V Input Voltage Range
No External Bias Supply Required
0 to 3.6V Input REFIN Range (MAX8553)
Automatically Sets VTT and VTTR to within ±1%
of 1/2 VREFIN- (MAX8553)
Low 0.6V Feedback Threshold (MAX8554)
200kHz/300kHz/400kHz/550kHz Selectable
Switching Frequencies
Adjustable Foldback Current Limit
Overvoltage Protection
Digital Soft-Start
Typical Operating Circuit
VIN
+5V
POK
REFIN
V+
EN/HSD
DH
MAX8553
POK VL
REFIN
BST
V+ LX
VOUT
REF DL
ILIM PGND
FSEL VTT
GND VTTR
VTTR
Pin Configurations appear at end of data sheet.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.




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