LM2595DSADJR4G ON Semiconductor, LM2595DSADJR4G Datasheet - Page 9

• Manufacturer Part Number: LM2595DSADJR4G
• Description: IC REG SW 1A STEPDOWN D2PAK-5
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of LM2595DSADJR4G

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.2 ~ 37 V
• Current - Output: 1A
• Frequency - Switching: 150kHz
• Voltage - Input: 4.5 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: D²Pak, TO-263 (5 leads + tab)
• Output Voltage: 1.23 V to 37 V
• Output Current: 1 A
• Input Voltage: 4.75 V to 40 V
• Switching Frequency: 150 KHz
• Operating Temperature Range: - 40 C to + 125 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 95 %
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PROCEDURE (ADJUSTABLE OUTPUT VERSION: LM2595)
Given Parameters:
1. Programming Output Voltage
2. Input Capacitor Selection (C
3. Catch Diode Selection (D1)
V
V
I
To select the right programming resistor R1 and R2 value (see
Figure 1) use the following formula:
Resistor R1 can be between 1.0 k and 5.0 kW. (For best
temperature coefficient and stability with time, use 1% metal
film resistors).
To prevent large voltage transients from appearing at the input
and for stable operation of the converter, an aluminium or
tantalum electrolytic bypass capacitor is needed between the
input pin +V
located close to the IC using short leads. This capacitor should
have a low ESR (Equivalent Series Resistance) value.
For additional information see input capacitor section in the
“Application Information” section of this data sheet.
A. Since the diode maximum peak current exceeds the
B. The reverse voltage rating of the diode should be at least
Load(max)
out
in(max)
regulator maximum load current the catch diode current
rating must be at least 1.2 times greater than the maximum
load current. For a robust design, the diode should have a
current rating equal to the maximum current limit of the
LM2595 to be able to withstand a continuous output short.
1.25 times the maximum input voltage.
= Regulated Output Voltage
V out + V
= Maximum DC Input Voltage
= Maximum Load Current
in
and ground pin GND This capacitor should be
ref
R2 + R1
1.0 )
Procedure
R2
R1
in
V
V
)
out
ref
where V
* 1.0
ref
= 1.23 V
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9
Given Parameters:
1. Programming Output Voltage (selecting R1 and R2)
2. Input Capacitor Selection (C
the input and ground pin provides sufficient bypassing.
3. Catch Diode Selection (D1)
is recommended) current rating is
diode or any suggested fast recovery diode in the Table 2.
V
V
I
Select R1 and R2:
A 220 mF, 50 V aluminium electrolytic capacitor located near
A. For this example, a 1.0 A (for a robust design 3.0 A diode
B. For V
Load(max)
out
in(max)
R2 = 3.07 kW, choose a 3.0k metal film resistor.
adequate.
= 5.0 V
V out + 1.23 1.0 )
R2 + R1
= 12 V
in
= 1.0 A
= 12 V use a 20 V 1N5817 (1N5820) Schottky
V out
V
ref
* 1.0
Example
R2
R1
in
)
+
Select R1 = 1.0 kW
1.23 V
5 V
* 1.0