MAX8581 Datasheet, PDF (1/9 Pages) Maxim Integrated Products – 2.5MHz/1.5MHz Step-Down Converters with 60m ohm Bypass in TDFN for CDMA PA Power

19-0593; Rev 0; 11/06
EVAALVUAAILTAIOBNLEKIT _{2.5MHz/1.5MHz Step-Down Converters}
with 60mΩ Bypass in TDFN for CDMA PA Power
General Description
The MAX8581/MAX8582 high-frequency step-down con-
verters are optimized for dynamically powering the power
amplifier (PA) in CDMA handsets. They integrate a high-
efficiency PWM step-down converter for medium- and
low-power transmission and a 60mΩ (typ) bypass mode
to power the PA directly from the battery during high-
power transmission. They use an analog input driven by
an external DAC to control the output voltage linearly for
continuous PA power adjustment. The MAX8581/
MAX8582 use an internal feedback network, and the
switching frequency is internally set to 2.5MHz and
1.5MHz, respectively.
Fast switching (up to 2.5MHz) and fast soft-start allow
the use of ceramic 2.2µF input and output capacitors
while maintaining low voltage ripple. The small 1.5µH to
3.3µH inductor size can be optimized for efficiency.
The MAX8581/MAX8582 are available in 10-pin, 3mm x
3mm TDFN packages (0.8mm max height).
Features
♦ 600mA Step-Down Converter
♦ 60mΩ (typ) Bypass Mode with Integrated FET
♦ Dynamically Adjustable Output from 0.4V to V_IN
♦ 2.5MHz and 1.5MHz Switching Frequency
♦ Small LC Components: 1.5µH to 3.3µH and 2.2µF
♦ Up to 94% Efficiency
♦ Low Output Ripple at All Loads
♦ 2.7V to 5.5V Input
♦ 0.1µA Shutdown Mode
♦ Output Short-Circuit Protection
♦ Thermal Shutdown
♦ 10-Pin, 3mm x 3mm TDFN Packag
Applications
WCDMA/NCDMA Cell Phones
Wireless PDAs, Smartphones
Ordering Information
PART*
PIN-
PACKAGE
TOP
MARK
PKG
CODE
MAX8581ETB+
10 TDFN-EP** ACT
T1033-1
MAX8582ETB+
10 TDFN-EP** ACU
T1033-1
*All devices are specified in the -40°C to +85°C extended
temperature range.
**EP = Exposed pad.
+Denotes lead-free package.
Typical Operating Circuit
INPUT
Li+ BATTERY
2.2μF
ON/OFF
ANALOG
CONTROL
OUTPUT
0.4V TO V_BATT
IN
OUT
1.5μH OR 3.3μH
MAX8581 LX
MAX8582
GND
2.2μF
SHDN
REFIN
HP
FORCED BYPASS
TOP VIEW
Pin Configuration
10 9 8 7 6
MAX8581/
MAX8582
+1 2 3 4 5
________________________________________________________________ Maxim Integrated Products 1
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