Micrel MIC2199 User Manual

MIC2199 Micrel

85.0

90.0

95.0

100.0

02468

EFFICIENCY (%)

I

LOAD

(A)

V

OUT

= 3.3V

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MIC2199

General Description

The MIC2199 is a high-power 300kHz synchronous buck
DC-to-DC controller housed in a small 4mm × 4mm MLF™
12-lead package. The MIC2199 operates from a wide 4.5V to
32V input and can be programmed for output voltages from

0.8V to 6V. The wide input voltage capability makes the
MIC2199 an ideal solution for point-of-load DC-to-DC con­version in 5V, 12V, 24V, and 28V systems.

The 300kHz switching frequency allows the use of a small
inductor and small output capacitors. The current mode PWM
control along with the external COMP pin allows for ease of
stability compensation and fast transient response across a
wide range of applications.

An all N-Channel synchronous architecture and powerful
output drivers allow up to 20A of output current capability.

For smaller external components, refer to the 500kHz
MIC2198.

The MIC2199 is available in a 12-pin 4mm × 4mm MLF™
package with a junction temperature range from –40°C to
125°C.

300kHz 4mm

××

× 4mm Synchronous Buck Converter

××

Features

• 4.5V to 32V input range

• 4mm × 4mm MLF™ package

• 300kHz PWM operation

• 95% efficiency

• Output voltage adjustable down to 0.8V

• 20A output current capability

• Drives all N-Channel MOSFETs

• Logic controlled micropower shutdown

• Cycle-by-cycle current limiting

• Adjustable undervoltage lockout

• Frequency foldback overcurrent protection

Applications

• Point-of-load DC-to-DC conversion from 5V, 12V,
24V, 28V supplies

• Telecom equipment

• Wireless modems

• Servers

• Base stations

Typical Application

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November 2004 1 MIC2199

Micro

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

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MIC2199BML

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4.5V–24V to 3.3V/7A Converter

LeadFrame are trademarks of Amkor Technology, Inc.

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Efficiency for

VIN = 5V and V

OUT

= 3.3V

MIC2199 Micrel

Ordering Information

Part Number Voltage Temperature Range Package

MIC2199BML Adj –40°C to +125°C 12-lead 4×4 MLF™

Pin Configuration

COMP

EN/UVLO

CSH

VOUT

VIN56

Pin Description

Pin Number Pin Name Pin Function

1 COMP Compensation (Output): Internal error amplifier output. Connect to capacitor

2 EN/UVLO Enable/Undervoltage Lockout (Input): Low-level signal powers down the

3 FB Feedback (Input): Regulates FB pin to 0.8V. See

4 CSH Current-Sense High (Input): Current limit comparator non-inverting input. A

5 VOUT Current-Sense Low (Input): Output voltage feedback input and inverting

6 VIN Unregulated Input (Input): +4.5V to +32V supply input.

7 VDD 5V Internal Linear-Regulator (Output): V

8 LSD Low-Side Drive (Output): High-current driver output for low-side N-Channel

9 GND Ground (Return).

10 BST Boost (Input): Provides drive voltage for the high-side MOSFET driver. The

11 VSW Switch (Return): High-side MOSFET driver return.

12 HSD High-Side Drive (Output): High-current driver output for high-side MOSFET.

1
2
3

FB

4

××

4

×4 MLF-12L (ML)

××

12
11
10

9
87LSD

HSD
VSW
BST
GND

VDD

or series RC network to compensate the regulator control loop.

controller. Input below the 2.5V threshold disables switching and functions
as an accurate undervoltage lockout (UVLO). Input below the threshold
forces complete micropower (<0.1µA) shutdown.

“Applications Information”

for resistor divider calculations.

built-in offset of 100mV between CSH and V
current-sense resistor set the current limit threshold level. This is also the
non-inverting input to the current sense amplifier.

input for the current limit comparator and the current sense amplifier.

drive supply voltage and internal supply bus for the IC. Bypass to GND with

4.7µF.

MOSFET. Voltage swing is between ground and VDD.

drive voltage is higher than the input voltage by VDD minus a diode drop.

This node voltage swing is between ground and VIN +5V minus a diode drop.

pins in conjunction with the

OUT

is the external MOSFET gate

DD

MIC2199 2 November 2004

MIC2199 Micrel

Absolute Maximum Ratings (Note 1)

Analog Supply Voltage (V
Digital Supply Voltage (V
Driver Supply Voltage (B
Sense Voltage (V

OUT

Enable Pin Voltage (V

) .......................................+34V

IN

) .........................................+7V

DD

) .................................. VIN + 7V

ST

, CSH) ............................. 7V to –0.3V

EN/UVLO

) ...................................... V

Operating Ratings (Note 2)

Analog Supply Voltage (V
Output Voltage Range (V
Junction Temperature (T
Package Thermal Resistance

IN

4×4 MLF-12L (θJA) .............................................. 60°C/W

) ........................ +4.5V to +32V

IN

) ........................ +0.8V to +6V

OUT

) ....................... –40°C to +125°C

J

Power Dissipation (PD)

4×4 MLF™ ................................. 665mW @ TA = 85°C

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

ESD, Note 3

Electrical Characteristics (Note 4)

VIN = VEN = 12V; TJ = 25°C, unless noted, bold values indicate –40°C ≤ TJ ≤ +125°C

Parameter Condition Min Typ Max Units

Feedback Voltage Reference (±1%) 0.792 0.8 0.808 V

Feedback Voltage Reference (±2%) 0.784 0.816 V

Feedback Voltage Reference 4.5V < VIN < 32V, 0 < (V

Feedback Bias Current 10 nA

Output Voltage Range 0.8 6 V

Output Voltage Line Regulation VIN = 4.5V to 32V, V

Output Voltage Load Regulation 25mV < (V

Input and VDD Supply

Quiescent Current excluding external MOSFET gate drive current 1.6 2.5 mA

Shutdown Quiescent Current V

Digital Supply Voltage (VDD)I

Undervoltage Lockout VIN upper threshold (turn-on threshold) 4.25 4.4 V

Enable/UVLO

Enable Input Threshold 0.6 1.1 1.6 V

UVLO Threshold 2.2 2.5 2.8 V

Enable Input Current V

Current Limit

Current Limit Threshold Voltage (V

Error Amplifier

Transconductance Error Amplifier GM

Oscillator Section

Oscillator Frequency 270 300 330 kHz

Maximum Duty Cycle 80 85 %

Minimum On-Time 170 200 ns

EN/UVLO

= 0mA to 5mA 4.7 5.0 5.3 V

L

VIN lower threshold (turn-off threshold) 3.95 4.1 V

EN/UVLO

CSH

CSH

= 0V 0.1 5 µA

= 5V 0.1 5 µA

– V

OUT

CSH

– V

OUT

) 55 75 95 mV

– V

CSH

– V

OUT

) < 60mV 0.5 %

) < 60mV (±3%) 0.776 0.824 V

OUT

= 60mV 0.03 %/V

0.2 mS

November 2004 3 MIC2199

MIC2199 Micrel

Parameter Condition Min Typ Max Units

Frequency Foldback Threshold measured at V

Foldback Frequency 75 kHz

Gate Drivers

Rise/Fall Time CL = 3000pF 60 ns

Output Driver Impedance source 5 8.5 Ω

sink 3.5 6 Ω

Driver Non-Overlap Time 80 ns

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. Devices are ESD protected; however, handling precautions are recommended. Human body model, 1.5k in series with 100pF.

Note 4. Specification for packaged product only.

pin 0.25 0.40 0.55 V

OUT

MIC2199 4 November 2004

MIC2199 Micrel

0.808

0.810

0.812

0.814

0.816

0.818

0.820

0 5 10 15 20 25 30 35

REFERENCE VOLTAGE (V)

SUPPLY VOLTAGE (V)

V

FB

Line Regulation

4.94

4.95

4.96

4.97

4.98

4.99

5.00

5.01

5.02

0 5 10 15 20 25 30

V

DD

REGULATOR VOLTAGE (V)

LOAD CURRENT (mA)

V

DD

Load Regulation

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0 5 10 15 20 25 30 35

FREQUENCY VARIATION (%)

SUPPLY VOLTAGE (V)

Oscillator Frequency

vs. Supply Voltage

Typical Characteristics

Quiescent Current

4.0

3.5

3.0

2.5

2.0

1.5

CURRENT (mA)

1.0

0.5

0.82

0.818

0.816

0.814

0.812

0.810

0.808

0.806

FB VOLTAGE (V)

0.804

0.802

0.8

vs. Temperature

V

FB

Shutdown

0

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

PWM

UVLO

Quiescent Current
vs. Supply Voltage

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

QUIESCENT CURRENT (mA)

0

4 9 14 19 24 29 34

SUPPLY VOLTAGE (V)

6.0

5.0

4.0

3.0

2.0

1.0

REGULATOR VOLTAGE (V)

DD

V

0.0

Line Regulation

0 4 8 121620242832

SUPPLY VOLTAGE (V)

Shutdown

V

DD

PWM

UVLO

5.20

5.15

5.10

5.05

5.00

4.95

4.90

REGULATOR VOLTAGE (V)

DD

4.85

V

4.80

88

86

84

82

80

November 2004 5 MIC2199

78

76

74

72

70

OVERCURRENT THRESHOLD (V)

V

DD

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

Overcurrent Threshold

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

Oscillator Frequency

vs. Temperature

10

8

6

4

2

0

-2

-4

-6

-8

FREQUENCY VARIATION (%)

-10

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

Current Limit

3.5

3

2.5

2

1.5

1

OUTPUT VOLTAGE (V)

0.5

0

012345

Foldback

VIN = 5V

V

= 3.3V

OUT

R

= 20mV

CS

OUTPUT CURRENT (A)