LM2671M-12/NOPB National Semiconductor, LM2671M-12/NOPB Datasheet - Page 16

• Manufacturer Part Number: LM2671M-12/NOPB
• Description: IC REG SIMPLE SWITCHER 8-SOIC
• Manufacturer: National Semiconductor
• Series: SIMPLE SWITCHER®r
• Type: Step-Down (Buck)r

Specifications of LM2671M-12/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 12V
• Current - Output: 500mA
• Frequency - Switching: 260kHz
• Voltage - Input: 6.5 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: *LM2671M-12; *LM2671M-12/NOPB; LM2671M-12

www.national.com
To simplify the buck regulator design procedure, National
Semiconductor is making available computer design software to be
used with the SIMPLE SWITCHER line of switching regulators.
LM267X Made Simple is available on (version 6.0) Windows 3.1,
NT, or 95 operating systems.
Given:
1. Programming Output Voltage (Selecting R
in Figure 3)
Use the following formula to select the appropriate resistor values.
LM2671 Series Buck Regulator Design Procedure (Adjustable Output)
V
V
I
F = Switching Frequency (Fixed at a nominal 260 kHz).
LOAD
OUT
IN
(max) = Maximum Input Voltage
PROCEDURE (Adjustable Output Voltage Version)
(max) = Maximum Load Current
= Regulated Output Voltage
Recommended
Application Voltage
Recommended
Application Voltage
3.3
2.5
3.3
10
12
15
5
FIGURE 14. RMS Current Ratings for Low ESR Electrolytic Capacitors (Typical)
Sprague 594D
+85°C Rating
+85°C Rating
AVX TPS
FIGURE 15. Recommended Application Voltage for AVX TPS and
Sprague 594D Tantalum Chip Capacitors Derated for 85°C.
Voltage
Rating
Voltage
Rating
6.3
6.3
10
20
25
35
4
1
and R
2
, as shown
16
Given:
1. Programming Output Voltage (Selecting R
in Figure 3)
Select R
V
V
I
F = Switching Frequency (Fixed at a nominal 260 kHz).
LOAD
OUT
IN
(max) = 28V
(max) = 500 mA
EXAMPLE (Adjustable Output Voltage Version)
= 20V
1
to be 1 kΩ, 1%. Solve for R
Recommended
Application Voltage
10004233
12
18
24
29
5
8
+85°C Rating
2
.
Voltage
Rating
10
16
20
25
35
50
1
and R
2
, as shown