MICREL MIC2182-5.0BSM, MIC2182BM, MIC2182BSM, MIC2182-5.0BM, MIC2182-3.3BM Datasheet

MIC2182 Micrel

MIC2182

High-Efficiency Synchronous Buck Controller

Final Information

General Description

Micrel’s MIC2182 is a synchronous buck (step-down) switch­ing regulator controller. An all N-channel synchronous archi­tecture and powerful output drivers allow up to a 20A output
current capabilty. The PWM and skip-mode control scheme
allows efficiency to exceed 95% over a wide range of load
current, making it ideal for battery powered applications, as
well as high current distributed power supplies.

The MIC2182 operates from a 4.5V to 32V input and can
operate with a maximum duty cycle of 86% for use in low­dropout conditions. It also features a shutdown mode that
reduces quiescent current to 0.1µA.

The MIC2182 achieves high efficiency over a wide output
current range by automatically switching between PWM and
skip mode. Skip-mode operation enables the converter to
maintain high efficiency at light loads by turning off circuitry
pertaining to PWM operation, reducing the no-load supply
current from 1.6mA to 600µA. The operating mode is inter­nally selected according to the output load conditions. Skip
mode can be defeated by pulling the PWM pin low which
reduces noise and RF interference.

The MIC2182 is available in a 16-pin SOP (small-outline
package) and SSOP (shrink small-outline package) with an
operating range from –40°C to +85°C.

Features

• 4.5V to 32V Input voltage range

• 1.25V to 6V Output voltage range

• 95% efficiency

• 300kHz oscillator frequency

• Current sense blanking

• 5Ω impedance MOSFET Drivers

• Drives N-channel MOSFETs

• 600µA typical quiescent current (skip-mode)

• Logic controlled micropower shutdown (IQ < 0.1µA)

• Current-mode control

• Cycle-by-cycle current limiting

• Built-in undervoltage protection

• Adjustable undervoltage lockout

• Easily synchronizable

• Precision 1.245V reference output

• 0.6% total regulation

• 16-pin SOP and SSOP packages

• Frequency foldback overcurrent protection

• Sustained short-circuit protection at any input voltage

• 20A output current capability

Applications

• DC power distribution systems

• Notebook and subnotebook computers

• PDAs and mobile communicators

• Wireless modems

• Battery-operated equipment

Typical Application

Q2*
Si4884

Q1*
Si4884

C11
22uf
35V
x2

10µH

D1
B140

L1

R2

0.02Ω
C7

220uf
10V ×2

V

OUT

3.3V/4A

GND

V

IN

4.5V to 30V*

GND

R7
100k

C3

0.1µF

2.2nF

C2

MIC2182-3.3BSM

10

VIN

C5

0.1µF

6

EN/UVLO

2

PWM
C4
1nF

1

SS

3

COMP

5

R1

SYNC

2k

SGND

4

VDD

BST

HSD

VSW

LSD

PGND

CSH
VOUT
VREF

D2

SD103BWS

11

14

C6

0.1µF

16

15

13

12

8

C13, 1nF

9

7

C1

0.1µF

C9

4.7µF
16V

* 30V maximum input voltage limit is due

to standard 30V MOSFET selection.
See “Application Information” section for

5V to 3.3V/10A and other circuits.

4.5V–30V* to 3.3V/4A Converter

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

June 2000 1 MIC2182

MIC2182 Micrel

Ordering Information

Part Number Voltage Temperature Range Package

MIC2182BM Adjustable –40°C to +85°C 16-pin narrow SOP
MIC2182-3.3BM 3.3V –40°C to +85°C 16-pin narrow SOP
MIC2182-5.0BM 5.0V –40°C to +85°C 16-pin narrow SOP
MIC2182BSM Adjustable –40°C to +85°C 16-pin narrow SSOP
MIC2182-3.3BSM 3.3V –40°C to +85°C 16-pin narrow SSOP
MIC2182-5.0BSM 5.0V –40°C to +85°C 16-pin narrow SSOP

Pin Configuration

SS

1

MIC2182

16

HSD

SS

MIC2182-x.x

1

16

HSD

PWM

COMP

SGND

SYNC

EN/UVLO

FB

CSH

2
3
4
5
6
7
8

15
14
13
12
11
10

Adjustable

16-pin SOP (M)

16-Pin SSOP (SM)

9

VSW
BST
LSD
PGND
VDD
VIN
VOUT

PWM

COMP

SGND
SYNC

EN/UVLO

VREF

CSH

2
3
4
5
6
7
8

15
14
13
12
11
10

Fixed

16-pin SOP (M)

16-Pin SSOP (SM)

9

VSW
BST
LSD
PGND
VDD
VIN
VOUT

MIC2182 2 June 2000

MIC2182 Micrel

Pin Description

Pin Number Pin Name Pin Function

1 SS Soft-Start (External Component): Connect external capacitor to ground to

reduce inrush current by delaying and slowing the output voltage rise time.
Rise time is controlled by an internal 5µA current source that charges an
external capacitor to VDD.

2 PWM PWM/Skip-Mode Select (Input): Low sets PWM-mode operation. 1nF

capacitor to ground sets automatic PWM/skip-mode selection.

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

or series RC network to compensate the regulator control loop.

4 SGND Small Signal Ground (Return): Route separately from other ground traces to

the (–) terminal of C

5 SYNC Frequency Synchronization (Input): Optional. Connect to external clock

signal to synchronize the oscillator. Leading edge of signal above the
threshold terminates the switching cycle. Connect to SGND if unused.

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

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.

7 (fixed) VREF Reference Voltage (Output): 1.245V output. Requires 0.1µf capacitor to

ground.

7 (adj) FB Feedback (Input): Regulates FB pin to 1.245V. See “Application Information”

for resistor divider calculations.

8 CSH Current-Sense High (Input): Current-limit comparator noninverting input. A

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

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

input for the current limit comparator and the current sense amplifier.
10 VIN [Battery] Unregulated Input (Input): +4.5V to +32V supply input.
11 VDD 5V Internal Linear-Regulator (Output): VDD is the external MOSFET gate

drive supply voltage and an internal supply bus for the IC. Bypass to SGND

with 4.7µF. VDD can supply up to 5mA for external loads.
12 PGND MOSFET Driver Power Ground (Return): Connects to source of synchro-

nous MOSFET and the (–) terminal of C
13 LSD Low-Side Drive (Output): High-current driver output for external synchronous

MOSFET. Voltage swing is between ground and VDD.
14 BST Boost (Input): Provides drive voltage for the high-side MOSFET driver. The

drive voltage is higher than the input voltage by VDD minus a diode drop.
15 VSW Switch (Return): High side MOSFET driver return.
16 HSD High-Side Drive (Output): High-current driver output for high-side MOSFET.

This node voltage swing is between ground and VIN + 5V – V

OUT

.

pins in conjunction with the

OUT

IN

diode drop

.

June 2000 3 MIC2182

MIC2182 Micrel

Absolute Maximum Ratings (Note 1)

Analog Supply Voltage (V

Digital Supply Voltage (VDD) .........................................+7V

Driver Supply Voltage (BST)....................................V

Sense Voltage (V
Sync Pin Voltage (V

OUT

SYNC

Enable Pin Voltage (V

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

IN

+7V

IN

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

) ................................ 7V to –0.3V

EN/UVLO

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

Operating Ratings (Note 2)

Analog Supply Voltage (V

Ambient Temperature (TA).........................–40°C to +85°C

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

Package Thermal Resistance

SOP (θJA) ..........................................................100°C/W

IN

SSOP (θJA)........................................................150°C/W

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

IN

Power Dissipation (PD)

SOP................................................400mW @ TA= 85°C

SSOP ............................................. 270mW @ TA= 85°C

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

ESD, Note 3

Electrical Characteristics

VIN = 15V; SS = open; V
noted

Parameter Condition Min Typ Max Units
MIC2182 [Adjustable], (Note 5)

Feedback Voltage Reference 1.233 1.245 1.257 V
Feedback Voltage Reference 1.220 1.245 1.270 V
Feedback Voltage Reference 4.5V < VIN < 32V, 0 < V
Feedback Bias Current 10 nA
Output Voltage Range 1.25 6 V
Output Voltage Line Regulation VIN = 4.5V to 32V, V
Output Voltage Load Regulation 25mV < (V
Output Voltage Total Regulation

MIC2182-3.3

Output Voltage 3.267 3.3 3.333 V
Output Voltage 3.234 3.3 3.366 V
Output Voltage 4.5V < VIN < 32V, 0 < V
Output Voltage Line Regulation VIN = 4.5V to 32V, V
Output Voltage Load Regulation 25mV < (V
Output Voltage Total Regulation

MIC2182-5.0

Output Voltage 4.95 5.0 5.05 V
Output Voltage 4.90 5.0 5.10 V
Output Voltage 6.5V < VIN < 32V, 0 < V
Output Voltage Line Regulation VIN = 6.5V to 32V, V
Output Voltage Load Regulation 25mV < (V
Output Voltage Total Regulation 0mV < (V

Input and VDD Supply

PWM Mode V
Skip Mode IL = 0mA, V
Shutdown Quiescent Current V
Digital Supply Voltage (VDD)I
Undervoltage Lockout VDD upper threshold (turn on threshold) 4.2 V

PWM

= 0V; V

= 5V; I

SHDN

0mV < (V

0mV < (V

PWM

EN/UVLO

= 0mA to 5mA 4.7 5.3 V

L

CSH

CSH

CSH

= 0V, excluding external MOSFET gate drive current 1.6 2.5 mA

= 0V 0.1 5 µA

= 0.1A; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; Note 4; unless

LOAD

– V

CSH

– V

CSH

CSH

CSH

CSH

PWM

– V

– V

– V

– V

– V

– V

) < 75mV (PWM mode only) 0.5 %

OUT

) < 75mV (full load range) 4.5V < VIN < 32V

OUT

– V

CSH

– V

CSH

) < 75mV (PWM mode only) 0.5 %

OUT

) < 75mV (full load range) 4.5V < VIN < 32V

OUT

– V

CSH

– V

CSH

) < 75mV (PWM mode only) 0.5 %

OUT

) < 75mV (full load range)

OUT

floating (1nF capacitor to ground) 600 1500 µA

< 75mV 1.208 1.245 1.282 V

OUT

= 50mV 0.03 %/V

OUT

0.6 %

< 75mV 3.201 3.3 3.399 V

OUT

= 50mV 0.03 %/V

OUT

0.8 %

< 75mV 4.85 5.0 5.150 V

OUT

= 50mV 0.03 %/V

OUT

6.5V < VIN < 32V

0.8 %

VDD lower threshold (turn off threshold) 4.1 V

MIC2182 4 June 2000

MIC2182 Micrel

Parameter Condition Min Typ Max Units
Reference Output (Fixed Versions Only)

Reference Voltage 1.220 1.245 1.270 V
Reference Line Regulation 6V < VIN < 32V 1 mV
Reference Load Regulation 0µA < I

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

EN/UVLO

Soft Start

Soft-Start Current VSS = 0V –3.5 –5 –6.5 µA

Current Limit

Current-Limit Threshold Voltage V

CSH

Error Amplifier

Error Sense Amplifier Gain 20

Current Amp

Current Sense Amplifier Gain 2.0

Oscillator Section

Oscillator Frequency 270 300 330 kHz
Maximum Duty Cycle 86 %
Minimum On-Time V

OUT

SYNC Threshold Level 0.7 1.3 1.9 V
SYNC Input Current V

SYNC

SYNC Minimum Pulse Width 200 ns
SYNC Capture Range Note 6 330 kHz
Frequency Foldback Threshold measured at VOUT pin 0.75 0.95 1.15 V
Foldback Frequency 60 kHz

Gate Drivers

Rise/Fall Time CL = 3000pF 60 ns
Output Driver Impedance source 5 8.5 Ω

sink 3.5 6 Ω

Driver Nonoverlap Time 80 ns

PWM Input

PWM Input Current V

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 sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4. 25°C limits are 100% production tested. Limits over the operating temperature range are guaranteed by design and are not production tested.
Note 5. VIN > 1.3 × V
Note 6. See applications information for limitations on the maximum operating frequency.

(for the feedback voltage reference and output voltage line and total regulation).

OUT

PWM

< 100µA2mV

REF

= 5V 0.1 5 µA

= V

OUT

= V

OUT(nominal)

+ 200mV 140 250 ns

75 100 135 mV

= 5V 0.1 5 µA

= 0V –10 µA

June 2000 5 MIC2182

MIC2182 Micrel

µ

(

)

Typical Characteristics

Quiescent Current

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

CURRENT (mA)

0.4

0.2

vs. Temperature

PWM

Skip

0

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

Quiescent Current

vs. Supply Voltage

1.5

1.0

0.5
0

0.5

-0.5

0.4

CURRENT (µA)

0.3

0.2

0.1
0

0 4 8 12 16 20 24 28 32

UVLO Mode

(mA)

SHUTDOWN

(µA)

SUPPLY VOLTAGE (V)

Quiescent Current

1.50

1.00

0.50

mA

-0.50

0.20

0.15

CURRENT

0.10

0.05

1.256

1.254

1.252

1.250

1.248

1.246

1.244

1.242

1.240

1.238

REFERENCE VOLTAGE (V)

1.236

vs. Temperature

UVLO Mode

0

0

-40 -20 0 20 40 60 80 100120140

V

(mA)

SHUTDOWN

(

A)

TEMPERATURE (°C)

(Fixed Versions)

REF

Line Regulation

0 4 8 121620242832

SUPPLY VOLTAGE (V)

Quiescent Current
vs. Supply Voltage

4.0

3.5

3.0

2.5

2.0

1.5

CURRENT (mA)

1.0

0.5
0

0 4 8 121620242832

INPUT VOLTAGE (V)

V

REF

1.260

1.250

1.240

1.230

1.220

1.210

REFERENCE VOLTAGE (V)

1.200

Load Regulation

0 200 400 600 800 1000

LOAD CURRENT (µA)

PWM

Skip

(Fixed Versions)

V

(Fixed Versions)

REF

1.260

1.255

1.250

1.245

REFERENCE VOLTAGE (V)

1.240

4.98

4.96

4.94

4.92

4.90

4.88

4.86

REGULATOR VOLTAGE (V)

4.84

DD

V

4.82

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

V

DD

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

5.0

4.8

4.6

4.4

4.2

REGULATOR VOLTAGE (V)

DD

V

4.0
0 4 8 121620242832

Oscillator Frequency

10

8
6
4
2
0

-2

-4

-6

-8

FREQUENCY VARIATION (%)

-10

-40 -20 0 20 40 60 80 100120140

V

DD

Line Regulation

SUPPLY VOLTAGE (V)

vs. Temperature

TEMPERATURE (°C)

V

DD

5.00

4.95

4.90

4.85

REGULATOR VOLTAGE (V)

DD

V

4.80

Load Regulation

0 5 10 15 20 25

LOAD CURRENT (mA)

Oscillator Frequency

vs. Supply Voltage

1.0

0.8

0.6

0.4

0.2
0

-0.2

-0.4

-0.6

-0.8

FREQUENCY VARIATION (%)

-1.0
0 4 8 121620242832

SUPPLY VOLTAGE (V)

MIC2182 6 June 2000

MIC2182 Micrel

0

1

2

3

4

5

012345678

OUTPUT VOLTAGE (V)

OUTPUT CURRENT (A)

Current-Limit

Foldback

VIN = 5V

V

OUT

= 3.3V

R

CS

= 15mΩ

Soft-Start Current

5.0

4.8

4.6

4.4

CURRENT (µA)

4.2

4.0

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

Overcurrent Threshold

0.12

0.11

0.10

0.09

0.08

OVERCURRENT THRESHOLD (V)

vs. Temperature

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

June 2000 7 MIC2182

MIC2182 Micrel

Block Diagrams

V

IN

C

IN

V

1.245V

DD

V

IN

EN/UVLO

6 11

SS

1

Control

Logic

PWM

2

Current
Limit

Reference

BG

V

VDD

VIN

10

VBST

14

HSD

16

VSW

15

LSD

13

PGND

12

Q2

Q1

D2

C

D1

BST

L1

4.7µF

R

CS

V

OUT

C

OUT

C

COMP

R

COMP

SYNC

COMP

RESET

Oscillator

5

3

MIC2182 [adj.]

PWM OUTPUT

PWM

CORRECTIVE
RAMP

PWM Mode
to Skip
Mode

Skip-Mode
Current
Limit

Low
Comp

Hysteresis
Comp

Error
Amp

100k

0.024V

0.07V

–2%V

BG

BG

V

= 0.2×10

G

m

Current
Sense
Amp

AV = 2

-3

CSH

8

VOUT

9

FB

7

SGND

4

R1



V 1.245V

=+

OUT

OUT(max)

= .0

V6V



1









R2

R1

R2

Figure 2a. Adjustable Output Voltage Version

MIC2182 8 June 2000

MIC2182 Micrel

Low
Comp

Current
Limit

Skip-Mode
Current
Limit

Hysteresis
Comp

V

BG

1.245V

V

BG

0.07V

–2%V

BG

Error
Amp

Control

Logic

V

IN

V

DD

PWM

PWM OUTPUT

CORRECTIVE
RAMP

RESET

Reference

Oscillator

0.024V

EN/UVLO

6 11

14

10

16

15

13

12

8

9

4

7

1

2

5

3

SS

PWM

SYNC

COMP

VREF

100k

G

m

= 0.2×10

-3

MIC2182-x.x

SGND

R2

50k

R1*

VOUT

CSH

VDD

VBST

C

IN

VIN

HSD

Q2

Q1

D1

D2

C

BST

R

CS

C

OUT

V

IN

V

OUT

L1

VSW

LSD

PGND

C

COMP

R

COMP

4.7µF

*82.5k for 3.3V Output

150k for 5V Output

AV = 2

Current
Sense
Amp

PWM Mode
to Skip
Mode

June 2000 9 MIC2182

Figure 2b. Fixed Output Voltage Versions