PM6685 STMicroelectronics, PM6685 Datasheet - Page 39

• Manufacturer Part Number: PM6685
• Description: IC CTLR DUAL SYNC STDN 5X5VFQFPN
• Manufacturer: STMicroelectronics

Specifications of PM6685

• Applications: Controller, Notebook Power System
• Voltage - Input: 6 ~ 28 V
• Number Of Outputs: 2
• Voltage - Output: -3.3V, 5V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN, 32-VFQFPN
• Output Voltage: 5 V, 3.3 V
• Output Current: 0.1 A
• Input Voltage: 5.5 V to 28 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 10 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PM6685
9
Other parts design
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Figure 38. VIN pin filter
Typical components values are: R=3.9 Ω and C=4.7 µF.
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Figure 39. Inductor current waveforms
Typical components values are: R=47 Ω and C=1 µF.
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Bypass the output of each linear regulator with 1 µF ceramic capacitor closer to the LDO pin
and a 4.7 µF tantalum capacitor (ESR=2 Ω). In most applicative conditions a 4.7 µF ceramic
output capacitor can be enough to ensure stability.
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VIN filter
A VIN pin low pass filter is suggested to reduce switching noise. The low pass filter is
shown in the next figure:
VCC filter
A VCC low pass filter helps to reject switching commutations noise:
VREF capacitor
A 10 nF to 100 nF ceramic capacitor on VREF pin must be added to ensure noise
rejection.
LDO3 and LDO5 output capacitors
Bootstrap circuit
The external bootstrap circuit is represented in the next figure:
Doc ID 11674 Rev 8
Other parts design
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