19-2954; Rev 2; 8/05
EVAALVUAAILTAIOBNLEKIT
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
General Description
The MAX8560/MAX8561/MAX8562 step-down DC-DC
converters are optimized for applications that prioritize
small size and high efficiency. They utilize a proprietary
hysteretic-PWM control scheme that switches with fixed
frequency and is adjustable up to 4MHz, allowing cus-
tomers to trade efficiency for smaller external compo-
nents. Output current is guaranteed up to 500mA, while
quiescent current is only 40µA (typ).
Internal synchronous rectification greatly improves effi-
ciency and eliminates the external Schottky diode
required in conventional step-down converters. Built-in
soft-start eliminates inrush current to reduce input
capacitor requirements. The MAX8561 features logic-
controlled output voltage, while the MAX8562 drives an
external bypass FET.
The MAX8560 is available in a 5-pin Thin SOT23 pack-
age. The MAX8561/MAX8562 are available in space-
saving 8-pin 3mm x 3mm Thin DFN packages.
Applications
Microprocessor/DSP Core Supplies
Cellular and Smart Phones
CDMA/RF Power-Amplifier Supplies
PDAs, DSC, and MP3 Players
Typical Operating Circuit
Features
♦ Up to 4MHz PWM Switching Frequency
♦ 500mA Guaranteed Output Current
♦ 40µA (typ) Quiescent Current
♦ Adjustable Output Voltage from 0.6V to 2.5V
♦ Logic-Controlled Output Voltage (MAX8561)
♦ Drives External Bypass FET (MAX8562)
♦ ±1.5% Initial Accuracy
♦ Soft-Start Eliminates Inrush Current
♦ Fast Voltage-Positioning Transient Response
♦ Internal Synchronous Rectifier
♦ 2.7V to 5.5V Input
♦ 0.1µA Logic-Controlled Shutdown
♦ Thermal Shutdown
♦ Thin SOT23 or Space-Saving 3mm x 3mm x
0.8mm TDFN Packages
Ordering Information
PART
TEMP RANGE
MAX8560EZK-T -40°C to +85°C
MAX8560EZK+T -40°C to +85°C
MAX8561ETA-T -40°C to +85°C
MAX8561ETA+T -40°C to +85°C
MAX8562ETA-T -40°C to +85°C
MAX8562ETA+T -40°C to +85°C
+Denotes lead-free package.
PIN-PACKAGE
5 Thin SOT23-5
5 Thin SOT23-5
8 TDFN
8 TDFN
8 TDFN
8 TDFN
TOP
MARK
ADRX
ADRX
AHD
AHD
AHE
AHE
Pin Configurations
INPUT
2.7V TO 5.5V
CIN
2.2µF
IN
LX
GND MAX8560
FB
ON/OFF
SHDN
L
1µH
R1
CFF
R2
OUTPUT
0.6V TO 2.5V
UP TO 500mA
COUT
2.2µF
TOP VIEW
IN 1
5 LX
MAX8560
GND 2
SHDN 3
4 FB
Thin SOT23-5
8 7 65
MAX8561/
MAX8562
1 2 34
TDFN
3mm × 3mm × 0.8mm
A "+" sign will replace the first pin indicator
on lead-free packages.
________________________________________________________________ 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.