Freescale Semiconductor
Technical Data
Document Number: MC34700
Rev. 4, 6/2008
9 to 18V, Quad Output, Integrated
MOSFET Power Supply
The 34700 is a compact, high efficiency power supply, with on-chip
power MOSFETs that feature three step down switching regulators
and one low dropout linear regulator. The switching regulators utilize
voltage mode control with external compensation, allowing flexibility in
optimizing the performance of the 34700 for a given application.
The 34700 is ideal for space constrained applications where
multiple power rails are required and simplicity of design and
implementation of the power supply is necessary. Over-voltage,
under-voltage, over-current, and over-temperature protection features
ensure robust and reliable operation. Fixed switching frequency,
internal soft start, and internal power MOSFETs enable rapid power
supply design and development.
The 34700 is well suited for power supply designs in wide variety of
applications, including set top boxes, cable modems, laser printers,
fax machines, point of sale terminals, small appliances, telecom line
cards, and DVD players.
34700
POWER SUPPLY
Features
• Three switching regulators: 2 synchronous and 1 non-synchronous
• One low dropout linear regulator
• Input current capability:
• 1.5A continuous on channel 1
• 1.25A continuous on channels 2 and 3
• 400mA continuous on channel 4
• Internal power MOSFETs on all channels
• Voltage feed forward on channel 1
• ±1.5% Output voltage accuracy on all channels
• Cycle-by-cycle current limit and short-circuit protection
• Fixed 800kHz switching frequency
• Internal soft start
• Over-voltage, under-voltage, and over-temperature protection
• Open-drain power good output signal
• Separate active-high enable input for each channel
• Pb-free packaging designated by suffix code EP
V
IN1
9V - 18V
VIN
VDDI
VGREG
Power Good
PGOOD
VIN1
VOUT1 VIN2 VIN3 BST1
SW1
COMP1
FB1
BST2
SW2
COMP2
Enable 1
Enable 2
Enable 3
Enable 4
EN1
EN1
EN1
EN_LDO
EP SUFFIX (Pb FREE)
98ASA10800D
32-Pin QFN
5 x 5mm
ORDERING INFORMATION
Device
MC34700EP/R2
Temperature
Range (T
A
)
-40°C to 85°C
Package
32 QFN
VOUT1
2.0 - 5.25V, 1.5A
VOUT2
0.7 - 3.6V, 1.25A
MC34700
FB2
BST3
SW3
COMP3
VOUT3
0.7 - 3.6V, 1.25A
AGND
GND2
GND3
FB3
LDO_VIN
LDO
VOUT4
0.7 - 3.6V, 0.4A
LDO_FB
Figure 1. MC34700 Simplified Application Diagram
Freescale Semiconductor, Inc. reserves the right to change the detail specifications,
as may be required, to permit improvements in the design of its products.
© Freescale Semiconductor, Inc., 2008. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
