MB39A132QN-G-ERE1 Fujitsu Semiconductor America Inc, MB39A132QN-G-ERE1 Datasheet - Page 39

• Manufacturer Part Number: MB39A132QN-G-ERE1
• Description: IC CONV DC-DC LI-ION 32QFN
• Manufacturer: Fujitsu Semiconductor America Inc

Specifications of MB39A132QN-G-ERE1

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: 25°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 865-1020

DS04–27265–3E
• Output capacitor selection
Since a high ESR causes the output ripple voltage to increase, a low-ESR capacitor is needs to be used in
order to reduce the output ripple voltage. Use a capacitor that has sufficient ratings to surge current generated
when the battery is inserted or removed. Generally, the ceramic capacitor is used as the output capacitor.
With the switching ripple voltage taken into consideration, the minimum capacitance required can be found
by the following formula.
Since an overshoot occurs in the DC/DC converter output voltage when a battery being charged is removed,
use a capacitor having sufficient withstand voltage. Generally, the capacitor having a rated withstand voltage
higher than the maximum input voltage is sued.
Moreover, use a capacitor having sufficient tolerance for allowable ripple current. The allowable ripple current
required can be found by the following formula.
Co ≥
Irms ≥
Co
ESR : Series resistance element of output capacitance [Ω]
ΔV
ΔIL : Inductor ripple current peak to peak value [A]
fosc : Switching frequency [Hz]
Irms : Allowable ripple current (Root-mean-square value) [A]
ΔIL : Inductor ripple current peak-to-peak value [A]
O
2π × fosc × (ΔV
: Output capacitance [F]
: Switching ripple voltage [V]
2√3
ΔIL
1
O
/ΔIL − ESR)
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