MICREL MIC4680BM, MIC4680-5.0BM, MIC4680-3.3BM Datasheet

MIC4680 Micrel

SW

L1

68µH

IN

FB

GND

SHDN

C2
220µF
16V

D1
B260A or
SS26

3.3V/1A

MIC4680-3.3BM

C1

15µF

35V

+6V to +34V

SHUTDOWN

ENABLE

5–8

4

32

1

Power
SOP-8

MIC4680

1A 200kHz SuperSwitcher™ Buck Regulator

Final Information

General Description

The MIC4680 SuperSwitcher™ is an easy-to-use fixed or
adjustable output voltage step-down (buck) switch-mode
voltage regulator. The 200kHz MIC4680 achieves up to 1.3A
of continuous output current over a wide input range in a
8-lead SOP (small outline package).

The MIC4680 is available in 3.3V and 5V fixed output ver­sions or adjustable output down to 1.25V.

The MIC4680 has an input voltage range of 4V to 34V, with
excellent line, load, and transient response. The regulator
performs cycle-by-cycle current limiting and thermal shut­down for protection under fault conditions. In shutdown
mode, the regulator draws less than 2µA of standby current.

The MIC4680 SuperSwitcher™ regulator requires a mini­mum number of external components and can operate using
a standard series of inductors and capacitors. Frequency
compensation is provided internally for fast transient re­sponse and ease of use.

The MIC4680 is available in the 8-lead SOP with a
–40°C to +125°C junction temperature range.

Features

• SO-8 package with up to 1.3A output current

• All surface mount solution

• Only 4 external components required

• Fixed 200kHz operation

• 3.3V, 5V, and adjustable output versions

• Internally compensated with fast transient response

• Wide 4V to 34V operating input voltage range

• Less than 2µA typical shutdown-mode current

• Up to 90% efficiency

• Thermal shutdown

• Overcurrent protection

Applications

• Simple 1A high-efficiency step-down (buck) regulator

• Replacement of TO-220 and TO-263 designs

• Efficient preregulator (5V to 2.5V, 12V to 3.3V, etc.)

• On-card switching regulators

• Positive-to-negative converter (inverting buck-boost)

• Simple battery charger

• Negative boost converter

• Higher output current regulator using external FET

T ypical Applications

Fixed Regulator Circuit

+5V to +34V

C1

15µF

SHUTDOWN

ENABLE

SuperSwitcher is a trademark of Micrel, Inc.

June 2000 1 MIC4680

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

35V

Power
SOP-8

Adjustable Regulator Circuit

MIC4680BM

IN

1

SHDN

GND

5–8

SW

FB

32

4

L1

68µH

D1
B260A or
SS26

R1

3.01k

R2

2.94k

2.5V/1A

C2
220µF
16V

MIC4680 Micrel

Ordering Information

Part Number Voltage Junction Temp. Range Package

MIC4680BM Adjustable –40°C to +125°C 8-lead SOP
MIC4680-3.3BM 3.3V –40°C to +125°C 8-lead SOP
MIC4680-5.0BM 5.0V –40°C to +125°C 8-lead SOP

Pin Configuration

IN

SW

FB

Pin Description

Pin Number Pin Name Pin Function

1 SHDN Shutdown (Input): Logic low enables regulator. Logic high (>1.6V) shuts

2 VIN Supply Voltage (Input): Unregulated +4V to +34V supply voltage.
3 SW Switch (Output): Emitter of NPN output switch. Connect to external storage

4 FB Feedback (Input): Connect to output on fixed output voltage versions, or to

5–8 GND Ground

1SHDN
2
3
4

8 GND

GND

7

GND

6

GND

5

SOP-8 (M)

down regulator.

inductor and Shottky diode.

1.23V-tap of voltage-divider network for adjustable version.

MIC4680 2 June 2000

MIC4680 Micrel

Absolute Maximum Ratings (Note 1)

Supply Voltage (V
Shutdown Voltage (V

Steady-State Output Switch Voltage (VSW) ..................–1V

), Note 3 ......................................+38V

IN

) .......................... –0.3V to +38V

SHDN

Operating Ratings (Note 2)

Supply Voltage (V

Junction Temperature (TJ) ...................................... +125°C

Package Thermal Resistance (θJA), Note 6............63°C/W

), Note 4 .......................... +4V to +34V

IN

Feedback Voltage [Adjustable] (VFB)..........................+12V

Storage Temperature (TS) ....................... –65°C to +150°C

ESD, Note 5

Electrical Characteristics

VIN = 12V; I

Parameter Condition Min Typ Max Units
MIC4680 [Adjustable]

Feedback Voltage (±1%) 1.217 1.230 1.243 V

Maximum Duty Cycle VFB = 1.0V 93 97 %
Output Leakage Current VIN = 34V, V

Quiescent Current VFB = 1.5V 7 12 mA

MIC4680-3.3

Output Voltage (±1%) 3.266 3.3 3.333 V

Maximum Duty Cycle VFB = 2.5V 93 97 %
Output Leakage Current VIN = 34V, V

Quiescent Current VFB = 4.0V 7 12 mA

MIC4680-5.0

Output Voltage (±1%) 4.950 5.0 5.05 V

Maximum Duty Cycle VFB = 4.0V 93 97 %
Output Leakage Current VIN = 34V, V

Quiescent Current VFB = 6.0V 7 12 mA

= 500mA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, Note 7; unless noted.

LOAD

(±2%) 1.205 1.255 V
8V ≤ V

≤ 34V, 0.1A ≤ I

IN

VIN = 34V, V

= 5V, VSW = 0V 50 500 µA

SHDN

= 5V, VSW = –1V 4 20 mA

SHDN

LOAD

≤ 1A, V

= 5V 1.193 1.230 1.267 V

OUT

(±3%) 3.201 3.399 V
6V ≤ VIN ≤ 34V, 0.1A ≤ I

= 5V, VSW = 0V 50 500 µA

SHDN

VIN = 34V, V

= 5V, VSW = –1V 4 20 mA

SHDN

≤ 1A 3.168 3.3 3.432 V

LOAD

(±3%) 4.85 5.15 V
8V ≤ V

≤ 34V, 0.1A ≤ I

IN

VIN = 34V, V

= 5V, VSW = 0V 50 500 µA

SHDN

= 5V, VSW = –1V 4 20 mA

SHDN

≤ 1A 4.800 5.0 5.200 V

LOAD

1.180 1.280 V

3.135 3.465 V

4.750 5.250 V

June 2000 3 MIC4680

MIC4680 Micrel

Parameter Condition Min Typ Max Units
MIC4680/-3.3/-5.0

Frequency Fold Back 30 50 100 kHz
Oscillator Frequency 180 200 220 kHz
Saturation Voltage I

Short Circuit Current Limit VFB = 0V, see Test Circuit 1.3 1.8 2.5 A
Standby Quiescent Current V

Shutdown Input Logic Level regulator off 2 1.6 V

Shutdown Input Current V

Thermal Shutdown 160 °C

Note 1. Exceeding the absolute maximum rating may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Absolute maximum rating is intended for voltage transients only, prolonged dc operation is not recommended.
Note 4. V
Note 5. Devices are ESD sensitive. Handling precautions recommended.
Note 6. Measured on 1" square of 1 oz. copper FR4 printed circuit board connected to the device ground leads.
Note 7. Test at TA = +85°C, guaranteed by design, and characterized to TJ = +125°C.

IN(min)

= V

+ 2.5V or 4V whichever is greater.

OUT

= 1A 1.4 1.8 V

OUT

= V

SHDN

V

SHDN

IN

= 5V (regulator off) 30 100 µA

1.5 µA

regulator on 1.0 0.8 V

= 5V (regulator off) –10 –0.5 10 µA

SHDN

V

= 0V (regulator on) –10 –1.5 10 µA

SHDN

V

Test Circuit

SHUTDOWN

Shutdown Input Behavior

ENABLE

ON

+12V

Device Under Test

IN

1

SHDN

GND

SOP-8 5–8

Current Limit Test Circuit

GUARANTEED

ON

0.8V

TYPICAL

ON

1V0V 1.6V V

Shutodwn Hysteresis

SW

FB

32

4

2V

68µH

GUARANTEED

OFF

TYPICAL

OFF

I

OFF

IN(max)

MIC4680 4 June 2000

MIC4680 Micrel

Typical Characteristics

5.06

5.05

5.04

5.03

5.02

5.01

5.00

4.99

4.98

OUTPUT VOLTAGE (V)

4.97

4.96

4.0

3.5

3.0

2.5

2.0

1.5

CURRENT (µA)

1.0

0.5

Line Regulation

I

= 1.0A

OUT

0 5 10 15 20 25 30 35

INPUT VOLTAGE (V)

Shutdown Current

vs. Temperature

VIN = 12V
V

= V

SHDN

IN

0

-50 -25 0 25 50 75 100 125

TEMPERATURE (°C)

5.04

5.02

5.00

4.98

OUTPUT VOLTAGE (V)

4.96

OUTPUT VOLTAGE (V)

Load Regulation

VIN = 12V
V

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

OUTPUT CURRENT (A)

Current Limit

6

5

4

3

2

1

0

Characteristic

VIN = 12V

0 0.2 0.4 0.6 0.8 1.01.2 1.4 1.6 1.8

OUTPUT CURRENT (A)

OUT

= 5V

Shutdown Current

100

CURRENT (µA)

202

201

200

199

198

FREQUENCY (kHz)

197

196

vs. Input Voltage

80

60

40

20

0

0 5 10 15 20 25 30 35

INPUT VOLTAGE (V)

Frequency vs.

Supply Voltage

0 5 10 15 20 25 30 35

SUPPLY VOLTAGE (V)

Frequency vs.

220

210

200

190

FREQUENCY (kHz)

180

-50 -25 0 25 50 75 100 125

80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

Temperature

TEMPERATURE (°C)

3.3V Output
Efficiency

6V

24V

12V

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

OUTPUT CURRENT (A)

Feedback Voltage

1.242

1.240

1.238

1.236

1.234

1.232

1.230

FEEDBACK VOLTAGE (V)

1.228

EFFICIENCY (%)

vs. Temperature

VIN = 12V
V

OUT

I

OUT

-50 -25 0 25 50 75 100 125 150

TEMPERATURE (°C)

5V Output

90
80
70
60
50
40
30
20
10

0

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

Efficiency

7V

24V

12V

OUTPUT CURRENT (A)

= 5V

= 1A

Saturation Voltage

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

SATURATION VOLTAGE (V)

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

vs. Temperature

VIN = 12V

= 5V

V

OUT

= 1A

I

LOAD

0

-50 -25 0 25 50 75 100 125

TEMPERATURE (°C)

12V Output

Efficiency

15V 24V

0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

OUTPUT CURRENT (A)

June 2000 5 MIC4680