NCP1587DR2G ON Semiconductor, NCP1587DR2G Datasheet - Page 12

• Manufacturer Part Number: NCP1587DR2G
• Description: IC CTLR SYNC BUCK LV 8-SOIC
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of NCP1587DR2G

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: Adjustable
• Current - Output: 1A
• Frequency - Switching: 275kHz
• Voltage - Input: 4.5 ~ 13.2 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Topology: Boost, Buck
• Output Voltage: 0.8 V to 5 V
• Output Current: 8 mA
• Switching Frequency: 300 KHz
• Duty Cycle (max): 80 %
• Operating Supply Voltage: 15 V
• Supply Current: 8 mA
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Synchronous Pin: No
• Number Of Pwm Outputs: 2
• On/off Pin: Yes
• Adjustable Output: Yes
• Switching Freq: 300KHz
• Duty Cycle: 80%
• Operating Supply Voltage (max): 13.2V
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC N
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

margin Ù R4 = 665 W
After choose R4 value, adjust R4 to get enough phase
2nd pole;
Choose C
C
P1
P1
+
+
to eliminate the noise;
2
2
F
P2
p
p
+ F
F
275 kHz
1
P2
sw
1
+ 275 KHz
Figure 14. Closed-loop Voltage Loop-gain of the NCP1587
R
C1
12 kW
+ 48.23 pF
http://onsemi.com
Blue curve: Gain-Frequency
Red curve: Gain-Frequency
(Phase margin = 80.285 degree, Gain margin = 19.362 dB)
12
Choose C
R2 = 10 kW, R3 = 10 kW, R4 = 665 W,
R
C20 = 3.3 nF
C1
The recommended compensation values are;
= 12.1 kW, C
P1
= 47 pF
C1
= 33 nF, C
P1
= 47 pF,