MC34704AEP Freescale Semiconductor, MC34704AEP Datasheet - Page 25

• 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

• 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 adjustable by means of an external
• A 240 mV current limit comparator will be used to program/
• The output can be adjusted up or down at 2.5% steps for
• Maximum output current is adjustable by means of an
• Uses a bootstrap network with an internal diode to power
• All gate drive circuits are supplied from VG.
• Uses integrated compensation
• The output is monitored for over-current and short-circuit
• The regulator is monitored for over-temperature conditions
• The output is monitored for under-voltage and over-
Operation Modes
• VG is in regulation AND
• There is no GrpD shutdown command through the I
• No faults exist that would cause GrpD to shut down
Analog Integrated Circuit Device Data
Freescale Semiconductor
MOSFETs (NVHV_LC) as its output stage
output is off (True Cut-Off)
resistor divider when in voltage regulation mode
sense the voltage drop across the current setting resistor
at the bottom of the LED string connected
output when the current regulation mode is selected
This will be used to program the maximum current flowing
and will regulate it
a total of 10% on each direction allowing Dynamic Voltage
Scaling
external resistor connected to the FB8 pin and then the
output current can be scaled down from the set maximum
in 16 steps through I
its synchronous MOSFET
conditions
voltage conditions
The switchers will be active when:
interface AND
2
C interface
DS(ON)
N-channel power
to the REG8
SW2
2
C
.
OVERALL EFFICIENCY ANALYSIS
every single regulator directly from the battery to obtain full
output capability:
• MOSFET Conduction Losses
• MOSFET Switching Losses (Except for REG7 due to
• MOSFET Gate Charging Losses
• MOSFET Deadtime Losses
• External Diode Losses (Only for REG7)
• Inductor Winding DC Losses
• Inductor Core Losses (Assumed to be 20% of DC Losses
• Output AC Losses
Efficiency Analysis
powered directly with 3.6 V nominal, battery voltage.
frequency of 1.5 MHz and 1.0 MHz for F
respectively, in this configuration. As a result, the following
numbers are valid for worst case operation conditions.
regulator with V2 at 3.3 V, V3 at 1.2 V, and V4 at 1.8 V.
In battery applications, it is highly recommended to power
Efficiency analysis includes the following losses:
external MOSFET and board layout dependence)
as a rule of thumb)
In this configuration, all of the regulators are supplied or
Efficiency was calculated using the maximum allowed
The following table shows the detailed analysis for each
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
VBAT
Figure 5. Overall Efficiency Analysis
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
REG1
REG2
REG3
REG4
REG5
REG6
REG7
REG8
FUNCTIONAL DESCRIPTION
V1 (5.0 V)
V2 (2.8 / 3.3 V)
V3 (1.2 V / 1.5 V / 1.8 V)
V4 (1.8 V / 2.5 V)
V5 (3.3 V)
V6 (15 V)
V7 (-7.0 V)
V8 (15 V)
SW1
and F
SW2
34704
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