IR3876MTRPBF International Rectifier, IR3876MTRPBF Datasheet - Page 16

• Manufacturer Part Number: IR3876MTRPBF
• Description: IC REG SYNC SUPIRBUCK 12A 17-QFN
• Manufacturer: International Rectifier
• Series: SupIRBuck™r
• Type: Step-Down (Buck)r

Specifications of IR3876MTRPBF

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.5 ~ 5 V
• Current - Output: 12A
• Frequency - Switching: Adj to 1MHz
• Voltage - Input: 3 ~ 21 V
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 17-PowerVQFN
• Part Status: Active
• Package: PQFN / 5 x 6
• Circuit: Single Output
• Iout (a): 12
• Switch Freq (khz): 0 - 1000
• Input Range (v): 3.0 - 21
• Output Range (v): 0.5 - 12
• Ocp Otp Uvlo Pre-bias Soft Start And: Constant On-Time + OVP no OTP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

IR3876MBF
LAYOUT RECOMMENDATION
V
IN
Bypass Capacitor:
One 1µF high quality ceramic capacitor should be
placed as near VCC pin as possible. The other
ON
end of capacitor can be connected to a via or
V
connected directly to GND plane. Use a GND
OUT
plane instead of a thin trace to the GND pin
IR3876
IR3871
because a thin trace have too much impedance.
OFF
C
IN
Boot Circuit:
C
OUT
C
should be placed near the BOOT and
BOOT
PHASE pins to reduce the impedance when the
upper MOSFET turns on.
Figure 20. Current Path of Power Stage
Power Stage:
Figure 20 shows the current paths and their
directions for the on and off periods. The on time
path has low average DC current and high AC
current. Therefore, it is recommended to place the
input
ceramic
capacitor,
upper,
and
lower
MOSFET in a tight loop as shown in Figure 20.
The purpose of the tight loop from the input
ceramic capacitor is to suppress the high
frequency (10MHz range) switching noise and
reduce Electromagnetic Interference (EMI). If this
path has high inductance, the circuit will cause
voltage spikes and ringing, and increase the
switching loss. The off time path has low AC and
high average DC current. Therefore, it should be
laid out with a tight loop and wide trace at both
ends of the inductor. Lowering the loop resistance
reduces the power loss. The typical resistance
value of 1-ounce copper thickness is 0.5mΩ per
square inch.
16