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1-A SIMPLE STEP-DOWN SWITCHING VOLTAGE REGULATOR
SLVS569E – JANUARY 2005 – REVISED JANUARY 2006
Electrical Characteristics
I
LOAD
= 200 mA, V
IN
= 12 V (unless otherwise noted) (see
PARAMETER
V
OUT
η
I
IB
f
o
V
SAT
Feedback voltage
Efficiency
Feedback bias current
Oscillator frequency
(1)
Saturation voltage
Maximum duty cycle
(3)
I
CL
I
L
I
Q
I
STBY
V
IH
ON/OFF logic input level
V
IL
I
IH
I
IL
(1)
(2)
(3)
(4)
ON/OFF input current
ON (V
OUT
= nominal voltage)
OFF (ON/OFF pin = 5 V)
ON (ON/OFF pin = 0 V)
Peak current
(1) (2)
Output leakage current
Quiescent current
(4)
Standby quiescent current
OFF (ON/OFF pin = 5 V)
OFF (V
OUT
= 0 V)
V
IN
= 40
(4)
, Output = 0 V
V
IN
= 40
(4)
, Output = –1 V
I
OUT
= 1 A
(2)
TEST CONDITIONS
V
OUT
= 5 V, I
LOAD
= 0.2 A
8 V
≤
V
IN
≤
40 V, V
OUT
= 5 V,
0.2 A
≤
I
LOAD
≤
1 A
V
IN
= 12 V, V
OUT
= 5 V, I
LOAD
= 1 A
V
OUT
= 5 V
T
J
25°C
25°C
Full range
25°C
25°C
Full range
25°C
Full range
25°C
Full range
25°C
25°C
Full range
25°C
25°C
25°C
25°C
Full range
25°C
Full range
25°C
12
0
2.2
2.4
1.2
1
0.8
30
10
µA
93
1.7
1.3
7.5
5
50
1.4
V
98
2.8
3.6
4
2
30
10
200
47
42
0.9
52
MIN
1.217
1.193
1.18
77
50
100
500
58
63
1.2
1.4
TYP
1.23
1.23
MAX
1.243
1.267
1.28
%
nA
kHz
V
%
A
mA
mA
µA
V
UNIT
In the event of an output short or an overload condition, self-protection features lower the oscillator frequency to
∼18
kHz and the
minimum duty cycle from 5% to
∼2%.
The resulting output voltage drops to
∼40%
of its nominal value, causing the average power
dissipated by the IC to lower.
Output is not connected to diode, inductor, or capacitor. Output is sourcing current.
Feedback is disconnected from output and connected to 0 V.
To force the output transistor off, FEEDBACK is disconnected from output and connected to 12 V.
3
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