MIC4690
Micrel
MIC4690
500kHz 1A SuperSwitcher™ Buck Regulator
General Description
The MIC4690 SuperSwitcher™ is an easy-to-use, 500kHz
step-down PWM voltage regulator. The MIC4690 achieves
over 1A of continuous output current over a wide input voltage
range in an 8-lead SO (small outline) package.
The high switching frequency of the MIC4690 allows the
smallest surface-mount inductors and capacitors to be used.
Internal compensation ensures fast transient response and a
minimum amount of external components.
The MIC4690 features a power SO-8 package with a special
lead frame that allows over 1A of continuous current. The
MIC4690, housed in an SO-8, can replace larger TO-220 and
TO-263 packages in many applications.
The MIC4690 allows for a high degree of safety. It has a wide
input voltage range of 4V to 34V, allowing for it to be used in
applications where input voltage transients may be present.
Built-in safety features include over-current protection, fre-
quency foldback protection, and thermal shutdown.
The MIC4690 is available in an 8-lead SO package with a
junction temperature range of –40°C to +125°C.
Features
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SO-8 package with over 1A output current
Fixed 500kHz operation
Wide 4V to 34Vinput voltage range
Output voltage adjustable to 1.23V
All surface mount solution
Internally compensated with fast transient response
Up to 85% efficiency
Overcurrent protection
Frequency foldback short-circuit protection
Thermal shutdown
Simple 1A step-down (buck) regulator
Replacement of TO-220 and TO-263 designs
12V to 5V/3.3V/2.5V/1.8V/1.5V conversion
5V to 2.5V/1.8V/1.5V conversion
On-card switching regulators
Hard disk drives
Cable modems
Positive-to-negative converters
Simple battery chargers
Applications
Typical Application
5V
SHUTDOWN
ENABLE
2
C1
22µF
10V
VIN
MIC4690BM
Power
SOP-8
SW
FB
3
L1
10µH
D1
2A
20V
2.5V/1A
R1
3.01k
R2
2.94k
C2
100µF
4V
1
SHDN
GND
4
5Ð8
2.5V Adjustable Converter
4V to 30V
(34V Transient)
C1
22
µ
F
10V
SHUTDOWN
ENABLE
2
VIN
MIC4690BM
Power
SOP-8
SW
FB
3
L1
18
µ
H
D1
2A
20V
1.8V/1A
R1
3.01k
R2
6.49k
C2
220
µ
F
4V
1
SHDN
GND
4
5Ð8
1.8V Adjustable Converter
SuperSwitcher is a trademark of Micrel, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2005
1
MIC4690
MIC4690
Micrel
Ordering Information
Part Number
Standard
MIC4690BM
Lead-Free
MIC4690YM
Voltage
Adjustable
Temperature Range
–40°C to +125°C
Package
8-lead SOP
Pin Configuration
SHDN 1
VIN 2
SW 3
FB 4
8 GND
7 GND
6 GND
5 GND
SOP-8 (M)
Pin Description
Pin Number
1
2
3
4
5-8
Pin Name
SHDN
VIN
SW
FB
GND
Pin Function
Shutdown (Input): Logic low enables regulator. Logic high (>1.5V) shuts
down regulator.
Supply Voltage (Input): Unregulated +4V to +30V continuous supply
voltage, with a maximum +34V transient voltage.
Switch (Output): Emitter of NPN output switch. Connect to external storage
inductor and Schottky diode.
Feedback (Input): Connect to output on fixed output voltage versions, or to
1.23V-tap of voltage-divider network for adjustable version.
Ground
MIC4690
2
April 2005
MIC4690
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
IN
),
Note 3 ......................................
+34V
Shutdown Voltage (V
SHDN
) ............................. –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
ESD Rating ..............................................................
Note 4
Operating Ratings
(Note 2)
Supply Voltage (V
IN
) ....................................... +4V to +30V
Junction Temperature Range (T
J
) ........... –40°C to +125°C
Package Thermal Resistance
(θ
JA
),
Note 5 ........................................................
63°C/W
(θ
JC
), ................................................................... 20°C/W
Electrical Characteristics
V
IN
= 12V, V
OUT
= 5V; I
LOAD
= 500mA; V
SHDN
= 0V, T
J
= 25°C, unless otherwise noted.
Bold
values indicate –40°C
≤
T
J
≤
+125°C.
Parameter
Condition
Min
Typ
Max
Units
Feedback Voltage
(±1%)
(±2%)
8V
≤
V
IN
≤
30V, 0.1A
≤
I
LOAD
≤
1A, V
OUT
= 5V
Maximum Duty Cycle
Quiescent Current
Standby Quiescent Current
V
FB
= 1.0V
V
FB
= 1.5V
V
SHDN
= 5V (regulator off)
V
SHDN
= 12V (regulator off)
Frequency Foldback
Oscillator Frequency
Saturation Voltage
Output Leakage Current
I
OUT
= 1A
V
IN
= 30V, V
SHDN
= 5V, V
SW
= 0V
V
IN
= 30V, V
SHDN
= 5V, V
SW
= –1V
Short Circuit Current Limit
Shutdown Pin Input Logic Level
V
FB
= 0V, V
OUT
= 0V, See
Test Circuit
regulator off
regulator on
Shutdown Pin Input Current
V
SHDN
= 5V (regulator off)
V
SHDN
= 0V (regulator on)
Thermal Shutdown @ T
J
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Exceeding the absolute maximum rating may damage the device.
With input voltages above the operating rating, the device may be damaged if a short-circuit is applied to the output. The device will otherwise
not be damaged up to its absolute maximum voltage rating.
Absolute maximum rating is intended for voltage transients only, prolonged dc operation is not recommended.
Devices are ESD sensitive. Handling precautions recommended.
Measured on 1" square of 1 oz. copper FR4 printed circuit board connected to the device ground leads.
1.217
1.205
1.193
1.180
90
1.230
1.230
93
7
30
1.5
220
1.243
1.255
1.267
1.280
V
V
V
V
%
12
100
mA
µA
µA
V
FB
= 0V
450
300
550
KHz
kHz
V
500
1.2
50
4
500
20
3.0
µA
mA
A
V
1.3
2
2.5
1.5
1.25
0.8
10
10
V
µA
µA
°C
–10
–10
–0.7
–1.5
160
April 2005
3
MIC4690
MIC4690
Micrel
Test Circuit
+12V
2
Device Under Test
3
VIN
SW
4
18µH
1
SHDN
GND
SOP-8
5–8
FB
I
Current Limit Test Circuit
Shutdown Input Behavior
OFF
ON
GUARANTEED
ON
TYPICAL
ON
0.8V
1.25V
1.5V
2V
GUARANTEED
OFF
TYPICAL
OFF
0V
V
IN(max)
Shutdown Hysteresis
MIC4690
4
April 2005
MIC4690
Micrel
Typical Characteristics
Reference Voltage
vs. Temperature
1.243
1.241
1.239
1.237
1.235
1.233
1.231
V
IN
= 12V
1.229
V
OUT
= 5V
1.227
I
OUT
= 100mA
1.225
1.223
-40 -20 0 20 40 60 80 100120140
TEMPERTURE (°C)
8.6
8.5 V
IN
= 12.0V
8.4 V
OUT
= 5.0V
8.3 I
OUT
= 0
8.2
8.1
8
7.9
7.8
7.7
7.6
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
Quiescent Current
vs. Temperature
80
78
EFFICIENCY (%)
Efficiency vs.
Output Current
CURRENT (mA)
VOLTAGE (V)
76
74
72
70
68
0
V
IN
= 12.0V
V
OUT
= 5.0V
0.2 0.4 0.6 0.8 1 1.2 1.4
OUTPUT CURRENT (A)
Efficiency
vs. Input Voltage
80
70
EFFICIENCY (%)
60
50
40
30
20 V
OUT
= 5V
= 1A
I
10
OUT
0
0
5
10 15 20 25 30 35 40
INPUT VOLTAGE (V)
FREQUENCY (kHz)
Frequency vs.
Temperature
600
500
FREQUENCY (kHz)
300
250
200
150
100
50
Frequency Foldback
vs. Temperature
400
300
200
100
0
-50
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 100mA
0
50
100
Temperature (°C)
150
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 100mA
0
50
100
Temperature (°C)
150
0
-50
Load Regulation
5.025
5.06
OUTPUT VOLTAGE (V)
V
IN
= 12V
V
OUT
= 5V
Line Regulation
3.5
Shutdown Current
vs. Temperature
SHUTDOWN CURRENT (µA)
3.0
2.5
2.0
1.5
1.0
0.5
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
V
SHDN
= V
IN
= 12V
V
= 5V
OUT
OUTPUT VOLTAGE (V)
5.020
5.015
5.010
5.005
5.000
0
5.04
5.02
5.00
4.98
4.96
0
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 500mA
5
10 15 20 25 30 35 40
INPUT VOLTAGE (V)
0.2 0.4 0.6 0.8 1 1.2 1.4
OUTPUT CURRENT (A)
Shutdown Hysteresis
vs. Temperature
SHUTDOWN PIN VOLTAGE (V)
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-40
OFF
ON
V
IN
= 12.0V
V
OUT
= 5.0V
I
OUT
= 100mA
0
40
80 120 160
TEMPERATURE (°C)
April 2005
5
MIC4690
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