L5981 STMicroelectronics, L5981 Datasheet - Page 32

• Manufacturer Part Number: L5981
• Description: IC REG SW STEP DOWN 1A 8-VFQFPN
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L5981

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 18 V
• Current - Output: 1A
• Frequency - Switching: 250kHz ~ 1MHz
• Voltage - Input: 2.9 ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-VFQFN, 8-VFQFPN
• Power - Output: 1.5W
• Output Voltage: 3 V
• Output Current: 1 A
• Input Voltage: 2.9 V to 18 V
• Switching Frequency: 220 KHz to 275 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 100 %
• Low Dropout Operation: 100 % duty cycle
• For Use With: 497-6385 - BOARD EVAL FOR L5981
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application information
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Figure 28. Load regulation
Figure 30. Load transient: from 0.2 A to 1 A
Figure 32. Short circuit behavior
V
V
1V/div
1V/div
OUT
OUT
OUTPUT
OUTPUT
SHORTED
SHORTED
V
V
100mV/div
100mV/div
AC coupled
AC coupled
I
I
200mA/div
200mA/div
L
L
OUT
OUT
0.25
0.15
0.05
0.3
0.2
0.1
OUT
OUT
10V/div
10V/div
0
0
F
SW
=250KHz
I
I
500mA/div
500mA/div
L
L
0.2
Time base 100μs/div
Time base 100μs/div
Load slew rate 2.5A/μs
Load slew rate 2.5A/μs
0.4
Io [A]
V
CC
0.6
=3.3V
Time base 5ms/div
Time base 5ms/div
C
C
L=15μH
L=15μH
F
F
SW
SW
0.8
OUT
OUT
V
=520KHz
=520KHz
=47μF
=47μF
V
CC
Doc ID 13004 Rev 6
CC
=5.0V
=12V
1
Figure 29. Line regulation
Figure 31. Soft-start
-0.05
0.35
0.25
0.15
0.05
0.4
0.3
0.2
0.1
0
2
I
I
500mA/div
500mA/div
L
L
4
6
Time base 1ms/div
Time base 1ms/div
8
VCC [V]
10
12
14
16
Io=1A
V
V
500mV/div
500mV/div
V
V
200mV/div
200mV/div
OUT
OUT
FB
FB
18
L5981