Rainbow Electronics MAX8640Z - Manual

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 24µA.
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 lead-free package (2.0mm x 2.1mm footprint,
1.1mm max height).
Applications
Microprocessor/DSP Core Power
I/O Power
Cell Phones, PDAs, DSCs, MP3s
Other Handhelds Where Space Is Limited
Features
♦ Tiny 6-Pin SC70 Package
♦ 500mA Guaranteed Output Current
♦ 4MHz or 2MHz PWM Switching Frequency
♦ Tiny External Components: 1µH/2.2µF or
2.2µH/4.7µF
♦ 24µA 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
MAX8640Y/MAX8640Z
500mA, 4MHz/2MHz Synchronous
Step-Down DC-DC Converters in SC70
________________________________________________________________ Maxim Integrated Products 1
19-3997; Rev 0; 5/06
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.
EVALUATION KIT
AVAILABLE
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
GND
OUT
1
+
6 IN
5 GND
LX
MAX8640Y
MAX8640Z
SC70
TOP VIEW
2
3 4 SHDN
Pin Configuration
L1
1 μH OR 2.2μH
C2
2.2 μF OR
4.7 μF
C1
2.2 μF
OUT
LX
GND
IN
SHDN ON/OFF
MAX8640Y
MAX8640Z
INPUT
2.7V TO 4.9V
OUTPUT
0.8V TO 2.5V
UP TO 500mA
Typical Operating Circuit
Ordering Information continued and Selector Guide appears
at end of data sheet.
*Contact factory for availability of each version.
+Denotes lead-free package.
Note: All devices are specified over the -40°C to +85°C
operating temperature range.