Micrel MIC2202 User Manual

MIC2202 Micrel

6

MIC2202

High Efficiency 2MHz Synchronous Buck

Converter 1µF Stable PWM Regulator

General Description

The Micrel MIC2202 is a high efficiency 2MHz PWM synchro­nous buck regulator. The fast 2MHz operation along with a
proprietary compensation scheme allows the smallest pos­sible external components. The MIC2202 can operate with
a 1µF ceramic output capacitor and a small, low DC-resis­tance, 2.2µH inductor, reducing system size and cost while
allowing a high level of efficiency.

The MIC2202 operates from 2.3V to 5.5V input and features
internal power MOSFETs that can supply over 600mA of
output current with output voltages down to 0.5V. The
MIC2202 implements a constant 2MHz pulse- width-modu­lation (PWM) control scheme which reduces noise in sensi­tive RF, audio, and communications applications. Addition­ally, the MIC2202 can be synchronized to an external clock,
or multiple MIC2202s can easily be daisy-chained with the
SYNCLOCK feature.

The MIC2202 has a high bandwidth loop (up to 500kHz)
which allows ultra fast transient response times. This is very
useful when powering applications that require fast dynamic
response such as CPU cores and RF circuitry in high
performance cellular phones and PDAs.

The MIC2202 is available in 10-pin MSOP and 3mm × 3mm
MLF™-10L package options with an operating junction
temperature range from –40°C to +125°C .

Features

• Input voltage range: 2.3V to 5.5V

• Output down to 0.5V/600mA

• 2MHz PWM operation

• Stable with 1µF ceramic output capcitor.

• Ultra-fast transient response (up to 500kHz GBW)

• Internal compensation

• All ceramic capacitors

• >95% efficiency

• Fully integrated MOSFET switches

• Easily synchronized to external clock

• SYNCLOCK feature to daisy chain multiple 2202s

• Requires only 4 external components

• 1% line and load regulation

• Logic controlled micropower shutdown

• Thermal shutdown and current limit protection

• 10-pin MSOP and 3mm×3mm MLF™-10L package
options

• –40°C to +125°C junction temperature range

Applications

• Cellular phones

• PDAs

• 802.11 WLAN power supplies

• FPGA/ASIC power supplies

• Dynamically adjustable power supply for CDMA/W­CDMA RF power amps

• DSL modems

• Tape drives

Typical Application

V

IN

2.3V to 5.5V
SYNC_IN

SYNC_OUT

EN

2.2µH

1
2
3
4

10

9
8
7
65

10k

10nF

1.78k

1µF

V

OUT

3.3V
600mA

Adjustable Output Synchronous Buck Converter

Micro

LeadFrame and MLF are trademarks of Amkor Technology, Inc.

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

May 2004 1 M9999-052104

Efficiency 3.3V

100

95
90
85
80
75

EFFICIENCY (%)

70
65
60

0 0.1 0.2 0.3 0.4 0.5 0.

4.2V

IN

5V

IN

L = 2.2µH
C

OUT

OUTPUT CURRENT (A)

OUT

= 1µF

MIC2202 Micrel

Ordering Information

Part Number Voltage Temperature Range Package Lead Finish

MIC2202BMM Adjustable –40°C to +125°C 10-pin MSOP-10 Standard
MIC2202BML Adjustable –40°C to +125°C 10-pin MLF™ Standard
MIC2202YMM Adjustable –40°C to +125°C 10-pin MSOP-10 Pb-Free
MIC2202YML Adjustable –40°C to +125°C 10-pin MLF™ Pb-Free

Pin Configuration

VIN

SYNC_IN

SYNC_OUT

EN FB65

1SW
2
3
4

10 GND

GND

9

GND

8

BIAS

7

MSOP-10 (MM)

Pin Description

Pin Number Pin Name Pin Function

1 SW Switch (Output): Internal power MOSFET output switches.
2 VIN Supply Voltage (Input): Requires bypass capacitor to GND.
3 SYNC_IN SYNC_IN for the MIC2202: Sync the main switching frequency to an

4 SYNC_OUT SYNC_OUT an open collector output.
5 EN A low level EN will power down the device, reducing the quiescent current to

6 FB Input to the error amplifier, connect to the external resistor divider network to

7 BIAS Internal circuit bias supply, nominally 2.3V. Must be de-coupled to signal

8, 9, 10 GND Ground.

EP GND Ground, backside pad.

SYNC_OUT

external clock.

under 1µA.

set the output voltage.

ground with a 0.01µF capacitor.

SW
VIN

SYNC_IN

EN FBEP

1
2
3
4
56

10

GND
GND

9

GND

8

BIAS

7

MLF™-10 (ML)

(Top View)

M9999-052104 2 May 2004

MIC2202 Micrel

Absolute Maximum Ratings

(Note 1)

Supply Voltage (VIN) .......................................................6V

Output Switch Voltage (V
Logic Input Voltage (V

) ..........................................6V

SW

EN

, V

SYNC_IN

)............... VIN to –0.3V

Power Dissipation .................................................... Note 3

Storage Temperature (T

) ....................... –65°C to +150°C

S

Operating Ratings

Supply Voltage (VIN) ................................... +2.3V to +5.5V

Junction Temperature (T
Package Thermal Resistance

MSOP-10L (θ

3mm×3mm MLF™-10L (θJA)...............................60°C/W

)................................................115°C/W

JA

(Note 2)

) ................ –40°C ≤ TJ ≤ +125°C

J

ESD Rating (Note 4) .....................................................2kV

Electrical Characteristics

TA = 25°C with VIN = 3.5V unless otherwise noted, bold values indicate –40°C < TJ < +125°C
Parameter Condition Min Typ Max Units

Supply Voltage Range 2.3 5.5 V
Quiescent Current EN = VIN; VFB = 0.55V (not switching) 350 450 µA

MIC2202 [Adjustable] Feedback 0.4875 0.500 0.5125 V
Voltage

Output Voltage Line Regulation V
Output Voltage Load Regulation 0mA < I
Bias Regulator Output Voltage 2.2 2.32 2.6 V
Maximum Duty Cycle VFB = 0.7V 100 %
Current Limit VFB = 0.7V 1 1.8 2.5 A
Switch ON-Resistance VIN = 3.5V, ISW = 300mA VFB = 0.35V 0.650 0.9 Ω

Enable Input Current 0.01 1 µA
Sync Frequency Range 1.6 2.5 MHz
SYNC_IN Threshold 0.7 1 1.7 V
Sync Minimum Pulse Width 10 ns
SYNC_IN Input Current 1 µA
Oscillator Frequency 1.8 2 2.2 MHz
Enable Threshold 0.5 0.9 1.3 V
Enable Hysteresis 20 mV
Over-temperature Shutdown 160 °C
Over-temperature Shutdown 20 °C

Hysteresis

(Note 5)

EN = 0V 0.01 1 µA

< 2V; VIN = 2.3V to 5.5V, I

OUT

< 500mA 0.1 0.5 %

LOAD

VIN = 3.5V, ISW = –300mA VFB = 0.55V 0.550 0.75 Ω

= 100mA 0.05 0.5 %

LOAD

Note 1. Exceeding the ABSOLUTE MAXIMUM RATINGS may damage device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Absolute maximum power dissipation is limited by maximum junction temperature where P
Note 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 5. Specification for packaged product only.

D(MAX)

= (T

J(MAX)–TA

) ÷ θJA.

May 2004 3 M9999-052104

MIC2202 Micrel

6

)

Typical Characteristics

Output Voltage

0.5050

0.5025

0.5000

0.4975

OUTPUT VOLTAGE (V)

0.4950

2.320

2.318

2.316

2.314

2.312

2.31

2.308

BIAS SUPPLY (V)

2.306

2.304

2.302

vs. Output Current

0 0.1 0.2 0.3 0.4 0.5

OUTPUT CURRENT (A)

Bias Supply

vs. Temperature

-40 -20 0 20 40 60 80 100 120

TEMPERATURE (°C)

Output Voltage

0.515

0.510

0.505

0.500

0.495

0.490

OUTPUT VOLTAGE (V)

0.485

(µA)

Q

I

vs. Temperature

-40-200 20406080100120

TEMPERATURE (°C)

Quiescent Current

vs. Supply Voltage

350
300
250
200
150
100

50

0

0123456

SUPPLY VOLTAGE (V)

VFB = 0V

V

BIAS

vs. Supply Voltage

2.5

2.0

1.5

(V)

BIAS

1.0

V

0.5

0

024

SUPPLY VOLTAGE (V

Quiescent Current

vs. Temperature

354
352
350
348
346
344

(µA)

342

Q

I

340
338
336
334
332

-40 -20 0 20 40 60 80 100120

TEMPERATURE (°C)

VFB = 0V

VIN= 3.6V

Frequency

2.40

2.30

2.20

2.10

2.00

1.90

1.80

FREQUENCY (MHz)

1.70

1.60

vs. Temperature

-40 -20 0 20 40 60 80 100120

TEMPERATURE (°C)

Enable Threshold

vs. Supply Voltage

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

ENABLE THRESHOLD (V)

0.1
0

2.3 2.8 3.3 3.8 4.3 4.8 5.3

SUPPLY VOLTAGE (V)

Enable On

Enable Off

Enable Threshold

vs. Temperature

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

ENABLE THRESHOLD (V)

0.1
0

-40 -20 0 20 40 60 80 100120

TEMPERATURE (°C)

3.6V

IN

M9999-052104 4 May 2004

MIC2202 Micrel

Block Diagram

V

IN

C

IN

SYNC_OUT

VIN

SYNC_IN

BIAS

EN

Internal

Supply

FB

Oscillator

Ramp

Generator

0.5V

PWM

Error
Amplifier

Comparator

MIC2202 Block Diagram

Driver

MIC2202

PGND

SW

V

OUT

C

OUT

May 2004 5 M9999-052104

MIC2202 Micrel

Functional Description

V

IN

VIN provides power to the output and to the internal bias
supply. The supply voltage range is from 2.3V to 5.5V. A
minimum 1µF ceramic is recommended for bypassing the
input supply.

Enable

The enable pin provides a logic level control of the output. In
the off state, supply current of the device is greatly reduced
(typically <1µA). Also, in the off state, the output drive is
placed in a “tri-stated” condition, where both the high side
P-Channel MOSFET and the low-side N-Channel are in an off
or non-conducting state. Do not drive the enable pin above
the supply voltage.

Sync_In

Sync_In pin enables the ability to change the fundamental
switching frequency. The Sync_In frequency has a minimum
frequency of 1.6MHz and a maximum sync frequency of

2.5MHz.
Careful attention should be paid to not driving the Sync_In pin

greater than the supply voltage. While this will not damage
the device, it can cause improper operation.

Sync_Out

Sync_Out is an open collector output that provides a signal
equal to the internal oscillator frequency. This creates the
ability for multiple MIC2202s to be connected together in a
master-slave configuration for frequency matching of the
converters. A typical 10kΩ is recommended for a pull-up
resistor.

Bias

The bias supply is an internal 2.3V linear regulator that
supplies the internal biasing voltage to the MIC2202. A 10nF
ceramic capacitor is required on this pin for bypassing. Do not
use the bias pin as a supply. The bias pin was designed to
supply internal power only.

Feedback

The feedback pin provides the control path to control the
output. A resistor divider connecting the feedback to the
output is used to adjust the desired output voltage. Refer to
the feedback section in the

“Applications Information”

for

more detail.

MIC2202
“Master”

VIN

10kΩ

SYNC_IN

SYNC_OUT

VIN

SYNC_IN

SYNC_OUT

SW

BIAS

FB

MIC2202

“Slave”

SW

BIAS

FB

Figure 1. Master-Slave Operation

M9999-052104 6 May 2004