BD9850FVM-TR Rohm Semiconductor, BD9850FVM-TR Datasheet - Page 10

• Manufacturer Part Number: BD9850FVM-TR
• Description: IC REG SW STEP DOWN HI EFF 8MSOP
• Manufacturer: Rohm Semiconductor
• Type: Step-Down (Buck)r
• Series: -r

Specifications of BD9850FVM-TR

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Current - Output: 200mA
• Frequency - Switching: 100kHz ~ 2MHz
• Voltage - Input: 4 ~ 9 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Power - Output: 587mW
• Mounting Style: SMD/SMT
• Pwm Type: Controller
• Frequency - Max: 2MHz
• Duty Cycle: -
• Voltage - Supply: 4 V ~ 9 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Description of external components
Setting of output voltage (BD9851EFV)
Setting of oscillation frequency (BD9850FVM)
Connecting a resistor to the RT pin (pin 2) allows for the setting of oscillation frequency.
• Setting of output voltage (BD9850FVM)
Setting of output voltage for the step-down application can be calculated by the formula below :
10000
1000
100
Vo = Vthea × (R1 + R2) / R2 [V]
(Vthea: Error Amp threshold voltage Typ. 1.0 [V])
• Step-down (CH1), Step-up (CH1)
• Step-down (CH2)
• Inverting (CH2)
Vo1 = Vthea × (R1 + R2) / R2 [V]
Vo2 = 2.5 – {(2.5 - V
V
(Vthea: Error Amp threshold voltage Typ. 1.0 [V])
However, set the INV2 pin voltage to 0.3 to 2.0 V
Vo2 = V
V
However, set the NON2 pin voltage to 0.3 to 2.0 V.
INV
1
NON
2 = 2.5 × R4 / (R3 + R4) [V]
2 = 2.5 × R4 / (R3 + R4) [V]
Fig.18 RT vs. Oscillation frequency
NON
2 × (R1 + R2) / R2 [V]
Timing resistance(RT) [kΩ]
10
INV
Setting procedure
Setting procedure
2) X (R1 + R2) / R1} [V]
100
1000
10/16
Fig.17 Setting procedure for BD9850FVM
oscillation frequency
R
RT
Vo
Vo2
Vo2
RT (2)
Vo1
R1
R2
R1
R2
R1
R2
R1
R2
Application
Application
R4
R3
R3
R4
INV (5)
INV1 (16)
V
NON2 (4)
INV2 (5)
V
INV2 (5)
NON2 (4)
REF
REF
(17)
(17)