Micrel MIC2141 User Manual

MIC2141 Micrel

查询MIC2141供应商

MIC2141

Micropower Boost Converter

Preliminary Information

General Description

The MIC2141 is a micropower boost switching regulator that
can operate from 3- or 4-cell nickel-metal-hydride batteries or
a single Li-ion cell. This regulator employs a constant 330kHz,
fixed 18% duty-cycle, gated-oscillator architecture.

The MIC2141 can be used in applications where the output
voltage must be dynamically adjusted. The device features a
control signal input which is used to proportionally adjust the
output voltage. The control signal input has a gain of 6,
allowing a 0.8V to 3.6V control signal to vary a 4.8V to 22V
output.

The MIC2141 requires only three external components to
operate and is available in a tiny 5-lead SOT-23 package for
space and power-sensitive portable applications. The
MIC2141 draws only 70µA of quiescent current and can
operate with an efficiency exceeding 85%.

Features

• Implements low-power boost, SEPIC, or flyback

• 2.5V to 14V input voltage

• 330kHz switching frequency

•<2µA shutdown current

•70µA quiescent current

• 1.24V bandgap reference

• typical output current 1mA to 10mA

• SOT-23-5 Package

Applications

• LCD bias supply

• CCD digital camera supply

Ordering Information

Part Number Junction Temp. Range Package

MIC2141-BM5 –40°C to +85°C SOT-23-5

Typical Application

(from DAC)

VC*

10µH

MIC2141

15
2
34

10µF

Variable
V

OUT

(V)
V

vs. Output Voltage

4.0

3.5

3.0

2.5

2.0

C

1.5

1.0

0.5
0

0 5 10 15 20 25

DAC-Controlled LCD Bias Voltage Supply

Control Voltage

V

(V)

OUT

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

June 2000 1 MIC2141

MIC2141 Micrel

Pin Configuration

GND

2

IN

13

Part
Identification

VCFB

SW

SAxx

45

SOT-23-5 (BM)

Pin Description

Pin Number Pin Name Pin Function

1 IN Input: +2.5V to +14V supply for internal circuity.
2 GND Ground: Return for internal circuitry and internal MOSFET (switch) source.
3 SW Switch Node (Input): Internal MOSFET drain; 22V maximum.
4 FB Feedback (Input): Output voltage sense node. Compared to V

input voltage.

5 VC Control (Input): Output voltage control signal input. Input voltage of 0.8V to

3.6V is proportional to 4.8V to 22V output voltage (gain of 6). If the pin is not
connected, the output voltage will be VIN – 0.5V.

control

C

MIC2141 2 June 2000

MIC2141 Micrel

Absolute Maximum Ratings (Note 1)

Supply Voltage (VIN) ...................................................+18V

Switch Voltage (V
Feedback Voltage (F
Control Input Voltage (VC), Note 3 ..VIN–200mV ≤ VC ≤ 4V

ESD Rating, Note 4 ...................................................... 2kV

)..................................................+24V

SW

)................................................+24V

B

Operating Ratings (Note 2)

Supply Voltage (VIN) .................................... +2.5V to +14V

Switch Voltage (V
Ambient Temperature (T

Junction Tempgserature (TJ) ................... –40°C to +125°C

Package Thermal Resistance

)...................................... +3V to +22V

SW

).........................–40°C to +85°C

A

SOT-23-5 (θJA)......................................................220°C/W

Electrical Characteristics

VIN = 3.6V, V

Parameter Condition Min Typ Max Units

Input Voltage 2.5 14 V
Quiescent Current Switch off, VIN = 3.6V 70 100 µA
Comparator Hysteresis 10 mV
Control Voltage Gain (V
Controlled Output Voltage, VC = 0.8V; 2.5V ≤ VIN ≤ 4.2V 4.85 5.0 5.15 V

Note 3

Load Regulation 100µA ≤ I
Line Regulation 2.5V ≤ VIN ≤ 12V; I
Switch On-Resistance ISW = 100mA, VIN = 3.6V 4 Ω

Oscillator Frequency 300 330 360 kHz
Oscillator Duty Cycle 15 18 %

OUT

= 5V; I

= 1mA; TJ = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted.

OUT

) 2.5V ≤ VIN ≤ 12V, V

OUT/VC

VC = 2.5V; 2.7V ≤ VIN ≤ 12V 14.55 15.0 15.45 V
VC = 3.4V; 3.6V ≤ VIN ≤ 12V 19.4 20.0 20.6 V

ISW = 100mA, VIN = 12V 2.5 Ω

≤ 1mA, V

OUT

= 15V 6

OUT

= 15V 0.25 1 %

OUT

≤ 1mA 0.05 0.2 %/V

OUT

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. VC = 4V sets V
Note 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

to 24V (absolute maximum level on VSW); VC must be ≤ VIN – 200mV.

OUT

June 2000 3 MIC2141

MIC2141 Micrel

µ

Typical Characteristcs

Feedback Current

vs. Output Voltage

25

20

15

10

5

FEEDBACK CURRENT (µA)

0

0 5 10 15 20 25

OUTPUT VOLTAGE (V)

Control Current

vs. Control Voltage

7
6
5
4
3
2
1

CONTROL CURRENT (nA)

0

01234

CONTROL VOLTAGE (V)

Control Voltage

vs. Output Voltage

20

VIN = 5V
L = 33µH

15

= 100mA

L = 33

= 150mA

L = 22µH

VIN = 2.5V

H

VIN = 5V

10

5

OUTPUT VOLTAGE (V)

15.00

14.95

14.90

14.85

OUTPUT VOLTAGE (V)

14.80

VIN = 3.6V

0

01234

CONTROL VOLTAGE (V)

Load Regulation

I

PEAK

I

PEAK

012345

LOAD CURRENT (mA)

Gain

vs. Output Voltage

6.4

6.3

6.2

6.1

GAIN

6.0

5.9

5.8

5.7
0 5 10 15 20 25

OUTPUT VOLTAGE (V)

15.0

14.8

14.6

14.4

14.2

OUTPUT VOLTAGE (V)

14.0

Line Regulation

24681012

INPUT VOLTAGE (V)

VIN = 5V

L = 33µH

L = 33µH
I

= 100µA

L

Oscillator Frequency

400

380

360

340

FREQUENCY (kHz)

320

300

vs. Input Voltage

2 4 6 8 10121416

INPUT VOLTAGE (V)

Frequency

350

340

330

320

FREQUENCY (kHz)

310

300

vs. Temperature

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

Quiescent Current

280
240
200
160
120

QUIESCENT CURRENT (µA)

vs. Input Voltage

80
40

0

0246810121416

INPUT VOLTAGE (V)

0.60

0.58

0.56

0.54

ON-TIME (µs)

0.52

0.50

Duty Cycle

vs. Temperature

20
19
18
17
16
15
14
13

DUTY CYCLE (%)

12
11
10

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

On-Time

vs. Temperature

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

MIC2141 4 June 2000

MIC2141 Micrel

14.00

14.20

14.40

14.60

14.80

15.00

-40 -20 0 20 40 60 80 100

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

0

10

20

30

40

50

60

70

80

90

100

01234

EFFICIENCY (%)

OUTPUT CURRENT (mA)

0

1

2

3

4

5

6

7

8

-40 -20 0 20 40 60 80 100

R

DS(on)

(Ω)

TEMPERATURE (°C)

Quiescent Current

vs. Temperature

88

86

84

82

80

QUIESCENT CURRENT (µA)

78

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

VIN = 5V

Switch Voltage Drop

vs. Temperature

VIN = 3.3V
I

= 100mA

D

0

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

(mV)

DS

V

800
700
600
500
400
300
200
100

Output Voltage

vs. Temperature

VIN = 5V
L = 33µH

Switch On-Resistance

vs. Temperature

VIN = 3.3V

Gain

6.00

5.98

5.96

GAIN

5.94

5.92

5.90

vs. Temperature

VIN = 5V

-40 -20 0 20 40 60 80 100

TEMPERATURE (°C)

Switch Voltage Drop

vs. Input Voltage

IDS = 100mA

0

2 4 6 8 10 12 14

INPUT VOLTAGE (V)

(mV)

DS

V

900
800
700
600
500
400
300
200
100

9
8
7
6
5
4
3
2

ON-RESISTANCE (Ω)

1
0

2 4 6 8 10 12 14

June 2000 5 MIC2141

On-Resistance vs.

Input Voltage

INPUT VOLTAGE (V)

Efficiency

BAT54HT1 Diode

1N4148 Diode

VIN = 5V
V

= 15V

OUT

L = 33µH

Ripple Voltage vs.

90
80
70
60
50
40
30
20

RIPPLE VOLTAGE (mV)

10

0

Input Voltage

L = 100µH

V

= 15V

OUT

I

= 1mA

L

24681012

INPUT VOLTAGE (V)