Micrel, Inc.
MIC4685
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
)
(1)
.................................................+34V
Enable Voltage (V
EN
)......................................... –0.3V to V
IN
Steady-State Output Switch Voltage (V
SW
) .......... –1V to V
IN
Feedback Voltage (V
FB
) ...............................................+12V
Storage Temperature (T
s
) .........................–65°C to +150°C
EDS Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)
(4)
..................................... +4V to +30V
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Resistance
SPAK-7 (θ
JA
) ...................................................11.8°C/W
SPAK-7 (θ
JC
).....................................................2.2°C/W
Electrical Characteristics
V
IN
= V
EN
= 12V; V
OUT
5V; I
OUT
= 500mA; T
A
= 25°C,
bold
values indicate –40°C< T
J
< +125°C, unless noted.
Parameter
MIC4685 [Adjustable]
Feedback Voltage
(±2%)
(±3%)
8V
≤
V
IN
≤
30V, 0.1A
≤
I
LOAD
≤
1A, V
OUT
= 5V,
Note 4
Feedback Bias Current
Maximum Duty Cycle
Output Leakage Current
Quiescent Current
Bootstrap Drive Current
Bootstrap Voltage
Frequency Fold Back
Oscillator Frequency
Saturation Voltage
Short Circuit Current Limit
Shutdown Current
Enable Input Logic Level
Enable Pin Input Current
Thermal Shutdown @ T
J
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. 2.5V of headroom is required between V
IN
and V
OUT
. The headroom can be reduced by implementing a bootstrap diode as seen on the 5V to 3.3V
circuit on page 1.
Condition
Min
1.210
1.198
1.186
1.173
Typ
1.235
1.235
50
Max
1.260
1.272
1.284
1.297
Units
V
V
V
V
nA
%
V
FB
= 1.0V
V
IN
= 30V, V
EN
= 0V, V
SW
= 0V
V
IN
= 30V, V
EN
= 0V, V
SW
= 1V
V
FB
= 1.5V
V
FB
= 1.5V, V
SW
= 0V
I
BS
= 10mA, V
FB
= 1.5V, V
SW
= 0V
V
FB
= 0V
I
OUT
= 1A
V
FB
= 0V,
See Test Circuit
V
EN
= 0V
regulator on
regulator off
V
EN
= 0V (regulator off)
V
EN
= 0V (regulator on)
–1
2
3.5
250
5.5
30
180
94
5
1.4
6
380
6.2
70
200
0.59
6
150
200
0.8
16
–0.83
160
50
120
225
500
20
12
µA
mA
mA
mA
V
kHz
kHz
V
A
µA
V
V
µA
mA
°C
January 2010
4
M9999-012610
MICREL [ MICREL SEMICONDUCTOR ]
