MC34704AEP Freescale Semiconductor, MC34704AEP Datasheet - Page 22

• Manufacturer Part Number: MC34704AEP
• Description: IC POWER MANAGEMENT 56-QFN
• Manufacturer: Freescale Semiconductor

Specifications of MC34704AEP

• Applications: Processor
• Current - Supply: 86mA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 56-QFN
• Output Voltage: 5 V
• Input Voltage: 2.7 V to 5.5 V
• Switching Frequency: 750 KHz to 2 MHz
• Mounting Style: SMD/SMT
• Number Of Outputs: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REG1 (34704A Only)
DC/DC regulator available only in the 34704A. Even though
REG1 is a synchronous regulator, it is recommended to have
a diode connected externally across its synchronous
MOSFET. When the battery voltage is above REG1’s output
(>5.0 V) as the case might be when connected to the USB
supply or wall adaptor, the REG1 power MOSFETs will be tri-
stated and the voltage on the output will be Battery minus the
diode drop. This will help maintain REG1’s output to a
maximum of 5.2 V and not allow it to drift all the way to 5.5 V.
allow pulse skipping.
received from the processor to turn on VOUT1, then the
isolation FET of REG1 would turn on gradually to avoid any
inrush current out of VG and to ramp the VOUT1 voltage in a
controlled manner.
shutting down and it will be held low by the discharge FET as
long as possible.
Characteristics
• It powers up directly from the battery
• Operates at a switching frequency equals to F
• Drives integrated low R
• It offers load disconnect from the input battery when the
• The output is ±4% accuracy
• Output voltage is set to 5.0 V by means of an internal
• The output can be adjusted up or down at 2.5% for a total
• Uses a bootstrap network with an internal diode to power
• All gate drive circuits are supplied from REG1’s own VG
• Uses integrated compensation
• The output is monitored for under-voltage and over-
• The output is monitored for over-current and short-circuit
• The regulator is monitored for over-temperature conditions
Operation Modes
• The IC is not in an under-voltage lockout AND
• No shutdown signal through the ONOFF pin is present
22
34704
FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
REG1 is a synchronous boost PWM voltage-mode control
The switcher will operate in DCM at very light loads to
On the 34704A, when the appropriate command is
REG1 VOUT1 will be discharged every time GrpA is
MOSFETs (NHV_HC) as its output stage
output is off (True Cutoff)
resistor divider
of 10% on each direction allowing Dynamic Voltage
Scaling
its synchronous MOSFET
output.
voltage conditions
conditions
The VG output is always active as long as:
AND
DS(ON)
REGUALATOR OVERVIEW WITH EFFICIENCY ANALYSIS
N-channel power
SW1
• There is no ALLOFF shutdown command through the I
• No faults exist that would cause the 34704 to shutdown
• VG output is available AND
• There is no GrpA shutdown command through the I
• No faults exist that would cause the VOUT1 to shut down
REG2
mode control DC/DC regulator.
when REG2 is powered up in the sequence.
allow pulse skipping.
shutting down and it will be held low by the discharge FET as
long as possible.
Characteristics
• It powers up directly from the battery
• Operates at a switching frequency equals to F
• Drives integrated low R
• The output is ±2% accuracy
• Output voltage is adjustable by means of an external
• The output can be adjusted up or down at 2.5% steps for
• Uses bootstrap networks with an internal diode to power
• All gate drive circuits are supplied from VG
• Uses external compensation
• The output is monitored for under-voltage and over-
• The output is monitored for over-current and short-circuit
• The regulator is monitored for over-temperature conditions
Operation Modes
• VG is in regulation AND
• There is no GrpB shutdown command through the I
• No faults exist that would cause GrpB to shut down
REG3
DC/DC regulator.
interface AND
The VOUT1 output will be active when:
interface AND
This is a 4-switch synchronous buck-boost PWM voltage-
See Power-Up Sequence on page 28
The switcher will operate in DCM at very light loads to
VOUT2 will be discharged every time the regulator is
MOSFETs (NHV_HC) as its output stage
resistor divider
a total of +17.5% to -20.0% on each direction allowing
Dynamic Voltage Scaling
its high side MOSFETs
voltage conditions
conditions
The switcher will be active when:
interface AND
This is a synchronous buck PWM voltage-mode control
Analog Integrated Circuit Device Data
DS(ON)
N-channel power
Freescale Semiconductor
for more details on
SW1
2
2
C
C
2
C