LM2670S-ADJ/NOPB National Semiconductor, LM2670S-ADJ/NOPB Datasheet - Page 8

• Manufacturer Part Number: LM2670S-ADJ/NOPB
• Description: IC REG SIMPLE SWITCHER TO-263-7
• Manufacturer: National Semiconductor
• Series: SIMPLE SWITCHER®r
• Type: Step-Down (Buck)r

Specifications of LM2670S-ADJ/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.2 ~ 37 V
• Current - Output: 3A
• Frequency - Switching: 260kHz
• Voltage - Input: 8 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: D²Pak, TO-263 (7 leads + tab)
• Primary Input Voltage: 40V
• No. Of Outputs: 1
• Output Voltage: 37V
• Output Current: 3A
• No. Of Pins: 7
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 3 - 168 Hours
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: *LM2670S-ADJ; *LM2670S-ADJ/NOPB; LM2670S-ADJ

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Other Applications
REGULATING V
It is possible to regulate the negative output of the LM2664
by use of a low dropout regulator (such as LP2980). The
whole converter is depicted in Figure 6. This converter can
give a regulated output from −1.8V to −5.5V by choosing the
proper resistor ratio:
OUT
FIGURE 6. Combining LM2664 with LP2980 to Make a Negative Adjustable Regulator
V
where, V
out
= V
ref
ref
(1 + R
= 1.23V
(Continued)
1
FIGURE 5. Combined Voltage Doubler and Inverter
/R
2
)
8
Note that, the following conditions must be satisfied simulta-
neously for worst case design:
V
V
in_max
in_min
+ I
+ I
out_max
out_min
<
>
V
V
out_min
out_max
x R
x R
out_max
out_min
+V
+V
drop_max
drop_min
10003112
(LM2664)
(LM2664)
10003124
(LP2980)
(LP2980)