MB39A132QN-G-ERE1 Fujitsu Semiconductor America Inc, MB39A132QN-G-ERE1 Datasheet - Page 37

• 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
Itop : Top value of ripple current of inductor [A]
Tr and Tf can be easily found by the following formula.
The FET loss of the low-side can be found by the following formula.
The FET voltage transiting between drain-source of the low-side is generally small. The SWFET loss is
omitted in this document as it is negligible.
Since the power for driving gate of SWFET is supplied by LDO in IC, the SWFET allowable maximum total
gate charge (QgTotalMax) is determined by the following formula.
P
Ibtm = I
QgTotalMax ≤
Tr =
Itop = I
LosideFET
ΔIL : Inductor ripple current peak to peak value [A]
Tr
Tf
Vgs(on) : Gate-Source voltage of high-side FET with Qgd [V]
P
P
I
V
V
R
QgTotalMax : High-side FET allowable maximum total charge [C]
f
Qgd
OMAX
OSC
O
LosideFET
RON_Loside
IN
on_Loside
5 − Vgs(on)
: FET turn-on time of high-side [s]
: FET turn-off time of high-side [s]
OMAX
OMAX
= P
Qgd × 4
: Gate-Drain charge of high-side FET [C]
: FET loss of low-side [W]
: FET continuity loss of low-side [W]
: Maximum charge current [A]
: Switching power supply voltage [V]
: Output voltage [V]
: FET ON resistance of synchronous rectification [Ω]
RON_Loside
−
−
: Oscillation frequency [Hz]
ΔIL
ΔIL
2
2
0.03
f
OSC
= I
OMAX
Tf =
2
× (1 −
Qgd × 1
Vgs(on)
V
V
IN
O
) × R
on_Loside
MB39A132
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