MC13892BJVL Freescale Semiconductor, MC13892BJVL Datasheet - Page 13

• Manufacturer Part Number: MC13892BJVL
• Description: IC PMU I.MX51/37/35/27 186MAPBGA
• Manufacturer: Freescale Semiconductor

Specifications of MC13892BJVL

• Applications: Battery Management, Display (LED Drivers), Handheld/Mobile Devices, Power Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 186-LFBGA
• Mounting Style: SMD/SMT
• Duty Cycle (max): 55 %
• Input Voltage: - 0.3 V to + 20 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 30 C
• Output Current: 30 mA
• Output Voltage: 3.3 V
• Topology: Boost
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Voltage - Supply: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

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To compensate for the voltage drop on the MC13892 power management IC switchers line due to the PCB wire
resistance, the PCB wire resistance needs to be placed inside the closed loop of the switcher. The goal is to stabilize
the voltage on that switcher line output.
The capacitor and coil components L and C are usually placed close to the MC13892 package. The voltage,
SWxOUT, is equal to the programmed output switcher voltage, minus the dropout caused by the PCB trace. This
dropout is also dependent on the DC load current on SWxOUT. In a typical configuration, the feedback loop is not
usually shielded.
The feedback signal is the core of the loop, with the functional information fed back and compared for reference (this
trace must be shielded from other signals). Moreover, it is a very high-impedance signal, so keep its trace thin and
far from the switching signal (the length of this trace does not matter).
Freescale recommends following the L and C configuration as designated. The output capacitor should be placed
near the point where the current is drawn on the output side of the PCB wire resistance, as shown in
PCB wire resistance is now inside the closed loop of the switcher, so it does not impact the DC voltage at SWxOUT.
The switcher feedback trace must be shielded, as this line is attached to a high-impedance point in the MC13892.
Any perturbation on this line must be minimized to ensure the stability of the switcher.
Figure 17
on the switcher line.
Analog Integrated Circuit Device Data
Freescale Semiconductor
Feedback Signals
shows the recommended configuration for the MC13892 power management IC, to stabilize the voltage
Figure 16. Placement and Layout Philosophy for a Recommended PCB.
Figure 15. Critical Traces on a Boost Converter.
Keep VERY short and wide
Keep short and wide
FB
FB
High di/dt trace
High di/dt trace
Low di/dt trace
Lower plane level,
keep far away from
switching signal
FEEDBACK SIGNALS
Figure
14. The
13892
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