SM8172A Datasheet, PDF (5/17 Pages) Nippon Precision Circuits Inc – 2-output Power Supply IC

SM8172A
11-3. DC/DC Converter
VIN1 = VIN2 = 5.0V, GND = PGND = 0V, Ta = 25°C unless otherwise noted.
Parameter
Pin Symbol
Condition
Rating
Unit
min
typ
max
Current consumption 1
Current consumption 2
Soft start time^*1*2
Output voltage range^*2
FB voltage
Maximum output current^*2*3
Switching frequency
Supply-side switch ON resistance
GND-side switch ON resistance
LX leakage current
Overcurrent protection circuit
operating current
VIN1, 2
VIN1, 2
–
–
FB
–
LX
LX
LX
LX
LX
I _DD1
I _DD2
t_SS
V_DCO
V _FB
I_DCO
f _OSC
R_ONP
R_ONN
I _LEAKLX
No load, switching stopped
FB = VIN1, LX = Open
I_DCO = 50mA
I_DCO = –50mA
Standby mode, LX = 1/2VIN
I_LIMITLX Supply-side switch
–
0.35
0.75
mA
–
2.5
5.5
mA
0.2
0.6
1.0
ms
0.8
–
1.8
V
0.588
0.6
0.612
V
900
–
–
mA
1.7
2.0
2.3
MHz
–
0.3
–
Ω
–
0.3
–
Ω
–1.0
–
1.0
µA
–
1.5
–
A
*1. The soft start time is the interval during which the output current is limited internally in the IC, and is different from the DC/DC converter output raise
time. If the maximum load current is output after soft start time startup, the output voltage does not fall. But, if the maximum load current is output
before soft start time startup, it should be careful that the output voltage may fall.
High
ENDCO
Low
LX switching start
Current limit
1.5A (typ)
Soft start time
DCOUT
1.8V
1.0V
42µsec (typ) 28µsec (typ)
The LX starts the switching operation after 42µs from ENDCO rising. After switching operation startup, the output current limit operates like linear
increase (load current = 0A). The DC/DC converter output voltage rise time varies with the load current, output capacitance, and other conditions.
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