BD9140MUV-E2 Rohm Semiconductor, BD9140MUV-E2 Datasheet - Page 9

• Manufacturer Part Number: BD9140MUV-E2
• Description: IC SWITCH REG 2A W/FET VQFN020
• Manufacturer: Rohm Semiconductor
• Series: -r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of BD9140MUV-E2

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 2.5 V ~ 6 V
• Current - Output: 2A
• Frequency - Switching: 500kHz
• Voltage - Input: 4.5 V ~ 13.2 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

●Selection of components externally connected
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BD9141MUV
www.rohm.com
1. Selection of inductor (L)
2. Selection of output capacitor (C
I
L
＊Current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases
If V
＊Select the inductor of low resistance component (such as DCR and ACR) to minimize dissipation in the inductor for
Fig.28 Output capacitor
efficiency. The inductor must be selected allowing sufficient margin with which the peak current may not exceed its
current rating.
better efficiency.
CC
Fig.27 Output ripple current
V
=3.3V, V
CC
V
CC
L
L=
IL
L
OUT
0.6×8×500k
(8-5)×5
=1.8V, f=1MHz, ΔI
Co
V
OUT
ESR
Co
ΔI
L
V
OUT
=6.25μ → 6.3[μH]
O
)
Output capacitor should be selected with the consideration on the stability region and the
equivalent series resistance required to smooth ripple voltage.
Output ripple voltage is determined by the equation (4)：
ΔV
(ΔI
*Rating of the capacitor should be determined allowing sufficient margin against output
voltage. A 22μF to 100μF ceramic capacitor is recommended.
Less ESR allows reduction in output ripple voltage.
L
=0.2×2A=0.4A, for example,(BD9141MUV)
L
OUT
: Output ripple current, ESR: Equivalent series resistance of output capacitor)
=ΔI
L
×ESR [V]・・・(4)
The inductance significantly depends on output ripple current.
As seen in the equation (1), the ripple current decreases as the
inductor and/or switching frequency increases.
Appropriate ripple current at output should be 20% more or less of
the maximum output current.
9/15
ΔI
ΔI
(ΔI
L
L
L=
L
=
=0.2×I
: Output ripple current, and f: Switching frequency)
(V
(V
CC
CC
OUT
L×V
ΔI
-V
-V
OUT
max. [A]・・・(2)
OUT
L
×V
CC
)×V
)×V
×f
CC
×f
OUT
OUT
[A]・・・(1)
[H]・・・(3)
Technical Note
2009.09 - Rev.B