NCP1587EDR2G ON Semiconductor, NCP1587EDR2G Datasheet - Page 12

• Manufacturer Part Number: NCP1587EDR2G
• Description: IC PWM CTLR BUCK UVLO 8-SOIC
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of NCP1587EDR2G

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: Adj to 0.8V
• Current - Output: 1A
• Frequency - Switching: 275kHz
• Voltage - Input: 4.5 V ~ 13.2 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• 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 NCP1587E
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,