LM2574DW-ADJR2G ON Semiconductor, LM2574DW-ADJR2G Datasheet - Page 8

• Manufacturer Part Number: LM2574DW-ADJR2G
• Description: IC REG SW 0.5A ADJ OUT 16-SOICW
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of LM2574DW-ADJR2G

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.23 ~ 37 V
• Current - Output: 500mA
• Frequency - Switching: 52kHz
• Voltage - Input: 4.75 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

circuit board is very important. Rapidly switching currents
associated with wiring inductance, stray capacitance and
parasitic inductance of the printed circuit board traces can
generate
electromagnetic interferences (EMI) and affect the desired
operation. As indicated in the Figure 16, to minimize
inductance and ground loops, the length of the leads
indicated by heavy lines should be kept as short as possible.
ground plane construction should be used.
As in any switching regulator, the layout of the printed
For best results, single−point grounding (as indicated) or
voltage
7.0 V − 40 V
Unregulated
DC Input
Unregulated
7.0 − 40 V
DC Input
transients
C
22 mF
in
V
in
1
which
C
22 mF
NOTE: Pin numbers in ( ) are for the SO−16W package.
in
Figure 16. Test Circuit and Layout Guidelines
(12)
C
C
D1
L1
R1
R2
in
out
4
V
in
1
−
−
−
−
−
−
Pwr
Gnd
(12)
(6)
Adjustable
Adjustable Output Voltage Versions
4
can
LM2574
22 mF, 60 V, Aluminium Electrolytic
220 mF, 25 V, Aluminium Electrolytic
Schottky, 1N5819
330 mH, (For 5.0 V
2.0 k, 0.1%
6.12 k, 0.1%
Fixed Output Voltage Versions
PCB LAYOUT GUIDELINES
2
Pwr
Gnd
Fixed Output
(6)
Sig
Gnd
LM2574
LM2574, NCV2574
(4)
V out + V
R2 + R1
Where V
between 1.0 kW and 5.0 kW
generate
2
http://onsemi.com
3
Sig
Gnd
(4)
(14)
ref
(3)
ON/OFF
ref
in
= 1.23 V, R1
V out
(5)
V
, 3.3 V
3
ref
7
1
Output
Feedback
8
1.0 ) R2
(14)
(3)
ON/OFF
– 1.0
out
(5)
(emitter of the internal switch) of the LM2574 should be
kept to a minimum in order to minimize coupling to sensitive
circuitry.
important to keep the sensitive feedback wiring short. To
assure this, physically locate the programming resistors near
to the regulator, when using the adjustable version of the
LM2574 regulator.
7
1
Output
Feedback
, use 100 mH)
R1
On the other hand, the PCB area connected to the Pin 7
Another sensitive part of the circuit is the feedback. It is
330 mH
D1
1N5819
L1
330 mH
D1
1N5819
L1
C
220 mF
out
C
220 mF
out
R2
6.12 k
R1
2.0 k
Load
V
out
Load
5.0 V
V
out