MAX8640Y_0710 Datasheet, PDF (1/11 Pages) Maxim Integrated Products – Tiny 500mA, 4MHz/2MHz Synchronous Step-Down DC-DC Converters

19-3997; Rev 2; 10/07
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Tiny 500mA, 4MHz/2MHz Synchronous
Step-Down DC-DC Converters
General Description
The MAX8640Y/MAX8640Z step-down converters are
optimized for applications where small size, high effi-
ciency, and low output ripple are priorities. They utilize
a proprietary PWM control scheme that optimizes the
switching frequency for high efficiency with small exter-
nal components and maintains low output ripple volt-
age at all loads. The MAX8640Z switches at up to
4MHz to allow a tiny 1µH inductor and 2.2µF output
capacitor. The MAX8640Y switches at up to 2MHz for
higher efficiency while still allowing small 2.2µH and
4.7µF components. Output current is guaranteed up to
500mA, while typical quiescent current is 28µA.
Factory-preset output voltages from 0.8V to 2.5V elimi-
nate external feedback components.
Internal synchronous rectification greatly improves effi-
ciency and replaces the external Schottky diode
required in conventional step-down converters. Internal
fast soft-start eliminates inrush current so as to reduce
input capacitor requirements.
The MAX8640Y/MAX8640Z are available in the tiny 6-
pin, SC70 (2.0mm x 2.1mm) and µDFN (1.5mm x
1.0mm) packages. Both packages are lead-free.
Applications
Microprocessor/DSP Core Power
I/O Power
Cell Phones, PDAs, DSCs, MP3s
Other Handhelds Where Space Is Limited
Typical Operating Circuit
Features
♦ Tiny SC70 and µDFN Packages
♦ 500mA Guaranteed Output Current
♦ 4MHz or 2MHz PWM Switching Frequency
♦ Tiny External Components: 1µH/2.2µF or
2.2µH/4.7µF
♦ 28µA Quiescent Current
♦ Factory Preset Outputs from 0.8V to 2.5V
♦ ±1% Initial Accuracy
♦ Low Output Ripple at All Loads
♦ Ultrasonic Skip Mode Down to 1mA Loads
♦ Ultra-Fast Line- and Load-Transient Response
♦ Fast Soft-Start Eliminates Inrush Current
Ordering Information
PART*
PIN-
PACKAGE
PKG
CODE
TOP
MARK
MAX8640YEXT08+T 6 SC70-6
X6S-1
ACQ
MAX8640YEXT11+T 6 SC70-6
X6S-1
ACR
MAX8640YEXT12+T 6 SC70-6
X6S-1
ACS
MAX8640YEXT13+T 6 SC70-6
X6S-1
ACG
MAX8640YEXT15+T 6 SC70-6
X6S-1
ADD
MAX8640YEXT16+T 6 SC70-6
X6S-1
ADB
MAX8640YEXT18+T 6 SC70-6
X6S-1
ACI
MAX8640YEXT19+T 6 SC70-6
X6S-1
ACH
MAX8640YEXT25+T 6 SC70-6
X6S-1
ACJ
*Contact factory for availability of each version.
+Denotes a lead-free package.
T = Tape and reel.
Note: All devices are specified over the -40°C to +85°C
operating temperature range.
Ordering Information continued and Selector Guide appears
at end of data sheet.
Pin Configurations
INPUT
2.7V TO 5.5V
C1
2.2μF
ON/OFF
L1
1μH OR 2.2μH
OUTPUT
0.8V TO 2.5V
UP TO 500mA
IN
LX
MAX8640Y
GND _MAX8640Z OUT
SHDN
C2
2.2μF OR
4.7μF
+
LX 1
TOP VIEW
+
6 IN
LX 1
6 IN
MAX8640Y
GND 2 _MAX8640Z 5 ^GND
MAX8640Y
GND 2 ^MAX8640Z 5 GND
OUT 3
4 _SHDN OUT ₃
4 SHDN
SC70
2.0mm x 2.1mm
μDFN
1.5mm x 1.0mm
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.