MC34280 Datasheet, PDF (1/20 Pages) ON Semiconductor – Power Supply & Management IC for Handheld Electronic Products

MC34280
PMEolaewncaetrgroeSnmuicpepPnltryoIdC&ufcotrsHandheld
The MC34280 is a power supply integrated circuit which provides
two boost regulated outputs and some power management supervisory
functions. Both regulators apply Pulse–Frequency–Modulation
(PFM). The main step–up regulator output can be externally adjusted
from 2.7V to 5V. An internal synchronous rectifier is used to ensure
high efficiency (achieve 87%). The auxiliary regulator with a built–in
power transistor can be configured to produce a wide range of positive
voltage (can be used for LCD contrast voltage). This voltage can be
adjusted from +5V to +25V by an external potentiometer; or by a
microprocessor, digitally through a 6–bit internal DAC.
The MC34280 has been designed for battery powered hand–held
products. With the low start–up voltage from 1V and the low quiescent
current (typical 35 µA); the MC34280 is best suited to operate from 1
to 2 AA/ AAA cell. Moreover, supervisory functions such as low
battery detection, CPU power–on reset, and back–up battery control,
are also included in the chip. It makes the MC34280 the best one–chip
power management solution for applications such as electronic
organizers and PDAs.
FEATURES:
• Low Input Voltage, 1V up
• Low Quiescent Current in Standby Mode: 35µA typical
• PFM and Synchronous Rectification to ensure high efficiency
(87% @200mA Load)
• Adjustable Main Output: nominal 3.3V @ 200mA max, with 1.8V
input
• Auxiliary Output Voltage can be digitally controlled by
microprocessor
• Auxiliary Output Voltage:
+5V @ 25mA max, with 1.8V input
+25V @ 15mA max, with 1.8V input
• Current Limit Protection
• Power–ON Reset Signal with Programmable Delay
• Battery Low Detection
• Lithium Battery Back–up
• 32–Pin LQFP Package
http://onsemi.com
32–LEAD LQFP
FTB SUFFIX
CASE 873A
MARKING DIAGRAM
MC34280F
TB
AWLYYWW
A = Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
32
1
PIN CONNECTIONS
32
1
VMAINFB
VBAT
ENABLE
VDD
PDELAY
VREF
AGND
IREF
MC34280
NC
VAUXBASE
VAUXCHG
VAUXBDV
VAUXFBN
VAUXREF
VAUXFBP
VAUXEN
APPLICATIONS:
• Digital Organizer and Dictionary
• Personal Digital Assistance (PDA)
• Dual Output Power Supply (For MPU, Logic, Memory, LCD)
• Handheld Battery Powered Device (1–2 AA/AAA cell)
ORDERING INFORMATION
Device
Package
Shipping
MC34280FTB
LQFP
250 Units/Tray
MC34280FTBR2
LQFP 1800 Tape & Reel
© Semiconductor Components Industries, LLC, 1999
1
February, 2000 – Rev. 2
Publication Order Number:
MC34280/D