FAN2110MPX_技术文档

Is Now Part of

To learn more about ON Semiconductor, please visit our website at

www.onsemi.com

Please note: As part of the Fairchild Semiconductor integration, some of the Fairchild orderable part numbers

will need to change in order to meet ON Semiconductor’s system requirements. Since the ON Semiconductor

product management systems do not have the ability to manage part nomenclature that utilizes an underscore

(_), the underscore (_) in the Fairchild part numbers will be changed to a dash (-). This document may contain

device numbers with an underscore (_). Please check the ON Semiconductor website to verify the updated

device numbers. The most current and up-to-date ordering information can be found at www.onsemi.com. Please

email any questions regarding the system integration to Fairchild_questions@onsemi.com.

ON Semiconductor and the ON Semiconductor logo are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number

of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON Semiconductor reserves the right

to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability

arising out of the application or use of any product or circuit, and speciﬁcally disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON

Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON

Semiconductor data sheets and/or speciﬁcations can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s

technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA

Class 3 medical devices or medical devices with a same or similar classiﬁcation in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended

or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its ofﬁcers, employees, subsidiaries, afﬁliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out

of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor

is an Equal Opportunity/Afﬁrmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.

September 2015

FAN2110 — 3-24 V Input, 10 A, High-Efficiency,

Integrated Synchronous Buck Regulator

Features

Description

The FAN2110 is a highly efficient, small footprint,

constant frequency, 10 A integrated synchronous Buck

regulator.

.

Wide Input Voltage Range: 3 V-24 V

Wide Output Voltage Range: 0.8 V to 80% V_IN

10 A Output Current

The FAN2110 contains both synchronous MOSFETs

and a controller/driver with optimized interconnects in

one package, which enables designers to solve high-

current requirements in a small area with minimal

external components. Integration helps to minimize

critical inductances making component layout simpler

and more efficient compared to discrete solutions.

1% Reference Accuracy Over Temperature

Over 93% Peak Efficiency

Programmable Frequency Operation: 200 KHz to

600 KHz

.

Fully Synchronous Operation with Integrated

Schottky Diode on Low-Side MOSFET Boosts

Efficiency

The FAN2110 provides for external loop compensation,

programmable switching frequency, and current limit.

These features allow design flexibility and optimization.

High frequency operation allows for all ceramic solutions.

.

Internal Bootstrap Diode

Power-Good Signal

The summing current mode modulator uses lossless

current sensing for current feedback and over-current

protection. Voltage feedforward helps operation over a

wide input voltage range.

Starts up on Pre-Bias Outputs

Accepts Ceramic Capacitors on Output

External Compensation for Flexible Design

Programmable Current Limit

Fairchild’s advanced BiCMOS power process,

combined with low-R_DS(ON)internal MOSFETs and a

thermally efficient MLP package, provide the ability to

dissipate high power in a small package.

Under-Voltage, Over-Voltage, and Thermal

Shutdown Protections

.

Internal Soft-Start

Output over-voltage, under-voltage, and thermal

shutdown protections help protect the device from

damage during fault conditions. FAN2110 also prevents

pre-biased output discharge during startup in point-of-

load applications.

5x6 mm, 25-Pin, 3-Pad MLP Package

Applications

.

Servers & Telecom

Related Application Notes

TinyCalc™ Calculator Design Tool

Graphics Cards & Displays

Computing Systems

Point-of-Load Regulation

Set-Top Boxes & Game Consoles

AN-8022 — TinyCalc™ Calculator User Guide

Ordering Information

Operating

Packing

Part Number

Temperature Range

Package

Method

FAN2110MPX

-40°C to 85°C

Molded Leadless Package (MLP) 5 x 6 mm

Tape and Reel

FAN2110EMPX

www.fairchildsemi.com

FAN2110 • Rev. 1.12

Typical Application

V_IN

P2

15

Boot

Diode

+5V

C_HF

C_IN

VCC

BOOT

1

C4

R_RAMP

Q1

Q2

C_BOOT

RAMP

PGOOD

EN

25

13

14

17

18

Power

Good

V_OUT

SW

P1

L

C_OUT

Enable

R_ILIM

PWM

+

DRIVER

ILIM

R_T

R(T)

PGND

P3

POWER

MOSFETS

COMP

AGND

24 NC

20

16

C2

R1

FB

19

C1

C3

R_BIAS

R2

R3

Figure 1. Typical Application Diagram

Block Diagram

5V

BOOT

VCC

Boot

Current Limit

Diode

IILIM

Comparator

VIN

ILIM

COMP

FB

Int ref

CBOOT

Error

Amplifier

R

S

Q

PWM

Comparator

Gate

Drive

Circuit

VOUT

SW

L

SS

VREF

COUT

CLK

Summing

Amplifier

AGND

PGND

OSC

RAMP

GEN

Current

Sense



EN

RAMP

Figure 2. Block Diagram

www.fairchildsemi.com

FAN2110 • Rev. 1.12

2

Pin Configuration

RAMP

NC

SW

P2

VIN

P1

SW

PGND

SW

P3

GND

Figure 3. MLP 5 x 6 mm Pin Configuration (Bottom View)

Pin Definitions

Pin #

P1, 6-12

P2, 2-5

Name

SW

Description

Switching Node. Junction of high-side and low-side MOSFETs.

Power Conversion Input Voltage. Connect to the main input power source.

VIN

P3, 21-23

PGND Power Ground. Power return and Q2 source.

High-Side Drive BOOT Voltage. Connect through capacitor (C_BOOT) to SW. The IC

1

BOOT

PGOOD

EN

includes an internal synchronous bootstrap diode to recharge the capacitor on this pin to

V_CCwhen SW is LOW.

Power-Good Flag. An open-drain output that pulls LOW when FB is outside the limits

specified in electrical specs. PGOOD does not assert HIGH until the fault latch is enabled.

13

14

ENABLE. Enables operation when pulled to logic HIGH or left open. Toggling EN resets the

regulator after a latched fault condition. This input has an internal pull-up when the IC is

functioning normally. When a latched fault occurs, EN is discharged by a current sink.

Input Bias Supply for IC. The IC’s logic and analog circuitry are powered from this pin.

This pin should be decoupled to AGND through a > 2.2 µF X5R / X7R capacitor.

15

16

17

VCC

AGND

ILIM

Analog Ground. The signal ground for the IC. All internal control voltages are referred to

this pin. Tie this pin to the ground island/plane through the lowest impedance connection.

Current Limit. A resistor (R_ILIM) from this pin to AGND can be used to program the current-

limit trip threshold lower than the internal default setting.

Oscillator Frequency. A resistor (R_T) from this pin to AGND sets the PWM switching

frequency.

18

19

20

24

25

R(T)

FB

Output Voltage Feedback. Connect through a resistor divider to the output voltage.

Compensation. Error amplifier output. Connect the external compensation network

between this pin and FB.

COMP

NC

No Connect. This pin is not used.

Ramp Amplitude. A resistor (R_RAMP) connected from this pin to V_INsets the ramp amplitude

and provides voltage feedforward functionality.

RAMP

www.fairchildsemi.com

FAN2110 • Rev. 1.12

3

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be

operable above the recommended operating conditions and stressing the parts to these levels is not recommended.

In addition, extended exposure to stresses above the recommended operating conditions may affect device

reliability. The absolute maximum ratings are stress ratings only.

Parameter

VIN to PGND

VCC to AGND

BOOT to PGND

BOOT to SW

Conditions

Min.

Max.

28

Unit

V

AGND=PGND

Continuous

6

V

35

V

-0.5

-5

6.0

V

24.0

30

V

SW to PGND

All other pins

ESD

Transient (t < 20 ns, f < 600 KHz)

V

-0.3

2.0

2.5

V_CC+0.3

V

Human Body Model, JEDEC JESD22-A114

Charged Device Model, JEDEC JESD22-C101

KV

Recommended Operating Conditions

The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended

operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not

recommend exceeding them or designing to absolute maximum ratings.

Symbol

V_CC

V_IN

Parameter

Bias Voltage

Conditions

VCC to AGND

VIN to PGND

Min.

4.5

3

Typ.

Max.

5.5

Unit

V

5.0

Supply Voltage

24

V

T_A

Ambient Temperature

Junction Temperature

Switching Frequency

-40

+85

+125

600

°C

T_J

°C

f_SW

200

kHz

Thermal Information

Symbol

Parameter

Min.

Typ.

Max.

+150

+300

Unit

°C

T_STG

T_L

Storage Temperature

-65

Lead Soldering Temperature, 10 Seconds

Thermal Resistance: Junction-to-Case

°C

P1 (Q2)

P2 (Q1)

P3

4

7

°C/W

W

_JC

4

Thermal Resistance: Junction-to-Mounting Surface⁽¹⁾

Power Dissipation, T_A=25°C⁽¹⁾

35

_J-PCB

P_D

2.8

Note:

1. Typical thermal resistance when mounted on a four-layer, two-ounce PCB, as shown in Figure 35. Actual results

are dependent on mounting method and surface related to the design.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

4

Electrical Specifications

Electrical specifications are the result of using the circuit shown in Figure 1 with V_IN=12 V, unless otherwise noted.

Symbol

Parameter

Conditions

Min. Typ. Max. Unit

Power Supplies

SW=Open, V_FB=0.7 V, V_CC=5 V,

f_SW=600 KHz

8

12

mA

I_CC

V_CCCurrent

Shutdown: EN=0, V_CC=5 V

Rising V_CC

7

10

µA

V

4.1

4.3

300

4.5

V_UVLO

Oscillator

f_SW

V_CCUVLO Threshold

Hysteresis

mV

255

540

300

600

50

345

660

65

KHz

ns

R_T=50 K to GND

R_T=24 K to GND

Frequency

Minimum On-Time⁽²⁾

Ramp Amplitude, Peak-to-Peak

Minimum Off-Time⁽²⁾

t_ONmin

16 V_IN, 1.8 V_OUT, R_T=30 K,

R_RAMP=200 K

V_RAMP

0.53

100

V

t_OFFmin

150

805

ns

Reference

Reference Voltage (see Figure 4 for

Temperature Coefficient)

V_FB

795

800

mV

Error Amplifier

G

DC Gain⁽²⁾

Gain Bandwidth Product⁽²⁾

Output Voltage⁽²⁾

80

12

85

15

dB

MHz

V

GBW

V_COMP

I_SINK

V_CC=5 V

0.4

1.5

0.8

3.2

Output Current, Sourcing

V_CC=5 V, V_COMP=2.2 V

V_CC=5 V, V_COMP=1.2 V

V_FB=0.8 V, 25°C

2.2

1.2

mA

nA

I_SOURCEOutput Current, Sinking

I_BIASFB Bias Current

Protection and Shutdown

-850 -650 -450

R_ILIM=182 K, 25°C, f_SW=500 KHz,

V_OUT=1.5 V, R_RAMP=243 K

16 Consecutive Clock Cycles⁽³⁾

Current Limit (see Circuit

I_LIM

12

14

16

-9

A

Description)⁽²⁾

V_CC=5 V, 25°C

I_ILIM

T_TSD

T_HYS

V_OVP

V_UVSD

V_FLT

I_LIMCurrent

-11

-10

+155

+30

115

73

µA

°C

Over-Temperature Shutdown⁽²⁾

Over-Temperature Hysteresis⁽²⁾

Over-Voltage Threshold

Under-Voltage Shutdown

Fault Discharge Threshold

Internal IC Temperature

2 Consecutive Clock Cycles⁽³⁾

16 Consecutive Clock Cycles⁽³⁾

Measured at FB Pin

110

68

121 %V_OUT

78

%V_OUT

mV

250

Measured at FB Pin (V_FB~500 mV)

V_{FLT_HYS}Fault Discharge Hysteresis

mV

Soft-Start

t_SS

t_EN

V_OUTto Regulation (T0.8)

Fault Enable/SSOK (T1.0)⁽²⁾

5.3

6.7

ms

f_SW=500 KHz

Continued on the following page…

www.fairchildsemi.com

FAN2110 • Rev. 1.12

5

Electrical Specifications (Continued)

Electrical specifications are the result of using the circuit shown in Figure 1 with V_IN=12 V, unless otherwise noted.

Symbol

Parameter

Conditions

Min. Typ. Max. Unit

Control Functions

V_EN

EN Threshold, Rising

V_CC=5 V

1.35 2.00

V

V_{EN_HYS}EN Hysteresis

250

800

1

mV

K

µA



R_EN

EN Pull-Up Resistance

I_{EN_DISC}EN Discharge Current

Auto-Restart Mode, V_CC=5 V

R_FBok

FB OK Drive Resistance

PGOOD LOW Threshold

800

FB < V_REF, 2 Consecutive Clock

Cycles⁽³⁾

V_{PGTH_LO}

-14

-11

-8

%V_REF

FB > V_REF, 2 Consecutive Clock

Cycles⁽³⁾

V_{PGTH_UP}

+7.0 +10.0 +13.5

0.4

V_{PG_LO}PGOOD Output Low

I_OUT< 2 mA

V_PGOOD=5 V

V

I_{PG_LK}

PGOOD Leakage Current

0.2

1.0

µA

Notes:

2. Specifications guaranteed by design and characterization; not production tested.

3. Delay times are not tested in production. Guaranteed by design.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

6

Typical Characteristics

1.010

1.005

1.000

0.995

0.990

1.20

1.10

1.00

0.90

0.80

-50

0

50

100

150

-50

0

50

100

150

Temperature (^oC)

Figure 4. Reference Voltage (V_FB

)

Figure 5. Reference Bias Current (I_FB

)

vs. Temperature, Normalized

1500

1200

900

600

300

0

1.02

1.01

1.00

0.99

0.98

600KHz

300KHz

-50

0

50

100

150

0

20

40

60

80

100

120

140

Temperature (^oC)

RT (K)

Figure 6. Frequency vs. R_T

Figure 7. Frequency vs. Temperature, Normalized

1.4

1.2

1

1.04

1.02

1.00

0.98

0.96

Q1 ~0.32%/°C

Q2 ~0.35%/°C

0.8

0.6

-50

0

50

100

150

0

50

100

150

Temperature (^oC)

Temperature (°C)

Figure 8. R_DSvs. Temperature, Normalized

(V_CC=V_GS=5 V), Figure 1

Figure 9. I_LIMCurrent (I_ILIM) vs. Temperature,

Normalized

FAN2110 • Rev. 1.12

www.fairchildsemi.com

7

Application Circuits

FAN2110

VIN

VCC

P2

15

+5V

10-20 V_IN

2.2u

X5R

10K

243K

PGOOD

13

24

20

3.3n

3 x 10u

X5R

V_OUT

RAMP

25

NC

2.49K

5.6n 120p

COMP

34

2.49K

BOOT

FB

ILIM

EN

1

* Cooper Industries

HC8-1R2-R

19

17

14

18

5.6n

0.1u

V_OU

S

P1

182K

1.2u *

R(T)



1.5

30.1K

2.80K

4 x 47u

X5R

AGND

PGND

P3

16

390p

3.3n

Figure 10. Application Circuit: 1.5 V_OUT, 10 A, 500 KHz (10 V-20 V_IN)

FAN2110

100

VIN

VCC

P2

+5V

V_OU

15

3.3-5.5 V_IN

2.2

u

10K

1u

X5R

PGOOD

13

3.3n

470u

10u

X5R

NC 24

140K

4.99K

3.3n 330p

COMP

RAMP

BOOT

20

25

1

100

2.49K

FB

ILIM

EN

* Cooper

HC8-R75-R

19

17

14

18

2.2n

u

0.1

V_OUT

S

P1

P3

182K

750n *

R(T)



1.5

30.1K

2.80K

4 x 47u

X5R

AGND

PGND

16

390p

3.3n

Figure 11. Application Circuit: 1.5 V_OUT, 10 A, 500 KHz (3.3 V-5.5 V_IN)

www.fairchildsemi.com

FAN2110 • Rev. 1.12

8

Typical Performance Characteristics

Typical operating characteristics using the circuit in Figure 10. V_IN=12 V, V_CC=5 V, T_A=25°C, unless otherwise specified.

FAN2110_1.5V_500Khz

FAN2110_3.3V_500Khz

100

95

90

85

80

75

70

100

95

90

85

80

75

70

VIN = 10V

VIN = 12V

VIN = 16V

VIN = 20V

VIN = 10V

VIN = 12V

VIN = 16V

VIN = 20V

0

2

4

6

8

10

0

2

4

6

8

10

Load Current (Amps)

Figure 12. 1.5 V_OUTEfficiency, 500 KHz

Figure 13. 3.3 V_OUTEfficiency, 500 KHz⁽⁴⁾

FAN2110_1.5V_300Khz

FAN2110_3.3V_300Khz

100

95

90

85

80

75

70

95

90

85

80

75

70

VIN = 10V

VIN = 12V

VIN = 16V

VIN = 20V

VIN = 10V

VIN = 12V

VIN = 16V

VIN = 20V

0

2

4

6

8

10

0

2

4

6

8

10

Load Current (Amps)

Figure 14. 1.5 V_OUTEfficiency, 300 KHz

Figure 15. 3.3 V_OUTEfficiency, 300 KHz⁽⁴⁾

FAN2110_2.5V_600Khz

FAN2110_1.5V_500K(3.3-5.5V)

95

90

85

80

75

70

100

95

90

85

80

75

70

VIN = 10V

VIN = 12V

VIN = 16V

VIN = 20V

VIN=3.5V

VIN=4.5V

VIN=5.5V

0

2

4

6

8

10

0

2

4

6

8

10

Load Current (Amps)

Figure 16. 2.5 V_OUTEfficiency ,600 KHz⁽⁴⁾

Figure 17. 1.5 V_OUTEfficiency, 500 KHz

(V_IN=3.3 V to 5 V), Figure 11

Note:

4. Circuit values for this configuration change in Figure 10.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

9

Typical Performance Characteristics (Continued)

Typical operating characteristics using the circuit in Figure 10. V_IN=12 V, V_CC=5 V, T_A=25°C unless otherwise specified.

Peak HS & LS Mosfet Tempr for 1.5V Output

(Measured on Demo Board)

Package Power Dissipation at various Vout(s)

Fsw = 500Khz

80

70

60

50

40

30

20

10

0

3

2.5

2

1.5

1

VIN=10V_HS

VIN=10V_LS

VIN=20V_HS

VIN=20V_LS

Vout = 1.5V

Vout = 1.8V

Vout = 3.3V

0.5

0

1

2

3

4

5

6

7

8

9

10

0

2

4

6

8

10

Load Current (A)

Load Current (Amps)

Figure 18. Peak MOSFET Temperatures, Figure 10

Figure 19. Device Dissipation Over V_OUTvs. Load

Line Regulation Data

Load Regulation

0.05

0.02

0

0.01

0

2

4

6

8

10

-0.05

-0.1

5

10

15

20

25

-0.01

-0.02

-0.03

-0.04

-0.15

-0.2

VIN=10V

VIN=20V

No Load

1A Load

-0.25

Input Voltage (Volts)

Load Current (Amps)

Figure 20. 1.5 V_OUTLine Regulation

Figure 21.

1.5 V_OUTLoad Regulation

Peak HS & LS Mosfet Tempr for 3.3V Output

(Measured on Demo Board)

Safe Operating Area curves for 70 Deg Temperature rise

VIN = 20V, Natural Convection

100

80

60

40

20

0

12

10

8

6

4

VIN=10V_HS

300K

500K

600K

VIN=10V_LS

VIN=20V_HS

VIN=20V_LS

2

0

2

4

6

8

10

12

14

1

2

3

4

5

6

7

8

9

10

Load Current (Amps)

Output Voltage (Volts)

Figure 23.

Typical 20 V_INSafe Operation Area

Figure 22. Peak MOSFET Temperatures, 3.3 V Output⁽⁵⁾

(SOA), 70C Ambient Temperature, Natural

Convection

Note:

5. Circuit values for this configuration change in Figure 10.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

10

Typical Performance Characteristics (Continued)

Typical operating characteristics using the circuit in Figure 10. V_IN=12 V, V_CC=5 V, T_A=25°C unless otherwise specified.

V_OUT

V_SW

EN

PGOOD

Figure 24. Startup, 10 A Load

Figure 25. Startup with 1.0 V Pre-Bias on V_OUT

V_OUT, 50mV/div

V_OUT

EN

V_SW,10V/Div

PGOOD

Figure 26. Shutdown, 10 A Resistive Load

Figure 27. V_OUTRipple and SW Voltage, 10 A Load

V_OUT, 200mV/div

I_OUT,5A/Div

EN, 2V/Div

Figure 28. Transient Response, 0-8 A Load,

5 A / µs Slew Rate

Figure 29. Restart on Short Circuit (Fault)

FAN2110 • Rev. 1.12

www.fairchildsemi.com

11

Circuit Description

PWM Generation

1.35V

EN

FB

Refer to Figure 2 for the PWM control mechanism.

FAN2110 uses the summing-mode method of control to

generate the PWM pulses. An amplified current-sense

signal is summed with an internally generated ramp and

the combined signal is compared with the output of the

error amplifier to generate the pulse width to drive the

high-side MOSFET. Sensed current from the previous

cycle is used to modulate the output of the summing

block. The output of the summing block is also

compared against a voltage threshold set by the R_LIM

resistor to limit the inductor current on a cycle-by-cycle

basis. R_RAMPresistor helps set the charging current for

the internal ramp and provides input voltage feed-

forward function. The controller facilitates external

compensation for enhanced flexibility.

2400 CLKs

0.8V

Fault

Latch

Enable

1.0V

0.8V

SS

3200 CLKs

4000 CLKs

T0.8

Initialization

T1.0

Once V_CCexceeds the UVLO threshold and EN is

HIGH, the IC checks for a shorted FB pin before

releasing the internal soft-start ramp (SS).

Figure 31. Soft-Start Timing Diagram

V_CCUVLO or toggling the EN pin discharges the

internal SS and resets the IC. In applications where

external EN signal is used, V_INand V_CCshould be

established before the EN signal comes up to prevent

skipping the soft-start function.

If the parallel combination of R1 and R_BIASis  1 K,

the internal SS ramp is not released and the regulator

does not start.

Enable

Startup on Pre-Bias

FAN2110 has an internal pull-up to the enable (EN) pin

so that the IC is enabled once V_CCexceeds the UVLO

threshold. Connecting a small capacitor across EN and

AGND delays the rate of voltage rise on the EN pin. The

EN pin also serves for the restart whenever a fault

occurs (refer to the Auto-Restart section). If the

regulator is enabled externally, the external EN signal

should go HIGH only after V_CCis established. For

applications where such sequencing is required,

FAN2110 can be enabled (after the V_CCcomes up) with

external control, as shown in Figure 30.

The regulator does not allow the low-side MOSFET to

operate in full synchronous mode until SS reaches 95%

of V_REF(~0.76 V). This enables the regulator to startup

on a pre-biased output and ensures that pre-biased

outputs are not discharged during the soft-start cycle.

Protections

The converter output is monitored and protected

against extreme overload, short-circuit, over-voltage,

under-voltage, and over-temperature conditions.

Under-Voltage Shutdown

If voltage on the FB pin remains below the under-

voltage threshold for 16 consecutive clock cycles, the

fault latch is set and the converter shuts down. This

protection is not active until the internal SS ramp

reaches 1.0 V during soft-start.

Figure 30. Enabling with External Control

Soft-Start

Once internal SS ramp has charged to 0.8 V (T0.8), the

output voltage is in regulation. Until SS ramp reaches

1.0 V (T1.0), the fault latch is inhibited.

To avoid skipping the soft-start cycle, it is necessary to

apply V_INbefore V_CCreaches its UVLO threshold. Normal

sequence for powering up would be VINVCCEN.

Soft-start time is a function of oscillator frequency.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

12

If auto-restart is not desired, tie the EN pin to the VCC

pin or pull it HIGH after V_CCcomes up with a logic gate

to keep the 1 µA current sink from discharging EN to

1.1V. Figure 32 shows one method to pull up EN to V_CC

for a latch configuration.

Over-Voltage Protection

If voltage on the FB pin exceeds 115% of V_REFfor two

consecutive clock cycles, the fault latch is set and

shutdown occurs.

A shorted high-side MOSFET condition is detected

when SW voltage exceeds ~0.7 V while the low-side

MOSFET is fully enhanced. The fault latch is set

immediately upon detection.

The OV/UV fault protection circuits above are active all

the time, including during soft-start.

Over-Temperature Protection (OTP)

The chip incorporates an over-temperature protection

circuit that sets the fault latch when a die temperature of

about 150°C is reached. The IC restarts when the die

temperature falls below 125°C.

Auto-Restart

Figure 32. Enable Control with Latch Option

After a fault, EN pin is discharged by a 1 µA current sink

to a 1.1 V threshold before the internal 800 K pull-up

is restored. A new soft-start cycle begins when EN

charges above 1.35 V.

Power-Good (PGOOD) Signal

PGOOD is an open-drain output that asserts LOW

when V_OUTis out of regulation, as measured at the FB

pin. Thresholds are specified in the Electrical

Specifications section. PGOOD does not assert HIGH

until the fault latch is enabled (T1.0) (see Figure 31).

Depending on the external circuit, the FAN2110 can be

configured to remain latched-off or to automatically

restart after a fault.

Table 1. Fault / Restart Configurations

EN Pin

Controller / Restart State

Pull to GND

OFF (Disabled)

No Restart – Latched OFF

(After V_CCComes Up)

Pull-up to V_CCwith 100K

Open

Immediate Restart After Fault

New Soft-Start Cycle After:

t_DELAY(ms)=3.9 • C(nf)

Cap. to GND

When EN is left open, restart is immediate.

www.fairchildsemi.com

FAN2110 • Rev. 1.12

13

Application Information

Bias Supply

operate at a lower switching frequency. The inductor

value is calculated by the following formula:

The FAN2110 requires a 5 V supply rail to bias the IC

and provide gate-drive energy. Connect a  2.2 µf

X5R or X7R decoupling capacitor between VCC and

AGND.

V_OUT

V_OUT (1-

)

(4)

Vin

L 

IL  f

where f is the oscillator frequency.

Since V_CCis used to drive the internal MOSFET

gates, supply current is frequency and voltage

Setting the Ramp Resistor Value

dependent. Approximate V_CCcurrent (I_CC

)

is

R_RAMPresistor plays a critical role in the design by

providing charging current to the internal ramp

capacitor and also serving as a means to provide

input voltage feedforward.

calculated by:

V_CC 5

227

I_CC

 4.58  [(

 0.013)(f 128)]

(1)

(mA )

where frequency (f) is expressed in KHz.

R_RAMPis calculated by the following formula:

(V_IN1.8)V_OUT

(31 2.05I_OUT)V_INf 10^6

Setting the Output Voltage

R_RAMP(K)



 2

(5)

The output voltage of the regulator can be set from

0.8V to 80% of V_INby an external resistor divider (R1

and R_BIASin Figure 1). For output voltages >3.3V,

output current rating may need to be de-rated

depending on the ambient temperature, power

dissipated in the package and the PCB layout. (Refer

to Thermal Information table on page 4, Figure 22,

and Figure 23.)

where frequency (f) is expressed in KHz.

For wide input operation, first calculate R_RAMPfor the

minimum and maximum input voltage conditions and

use larger of the two values calculated.

In all applications, current through the R_RAMPpin must

be greater than 10 µA from the equation below for

proper operation:

The external resistor divider is calculated using:

V_IN1.8

R_RAMP 2

V_OUT 0.8V

R1

0.8V

 10A

(2)

(6)



 650nA

R_BIAS

Connect R_BIASbetween FB and AGND.

If the calculated R_RAMPvalues in Equation (5) result in

a current less than 10 µA, use the R_RAMPvalue that

satisfies Equation (6). In applications with large Input

ripple voltage, the R_RAMPresistor should be

adequately decoupled from the input voltage to

minimize ripple on the ramp pin. For example, see

Figure 11.

If R1 is open (see Figure 1), the output voltage is not

regulated and a latched fault occurs after the SS is

complete (T1.0).

If the parallel combination of R1 and R_BIASis  1K,

the internal SS ramp is not released and the regulator

does not start.

Setting the Current Limit

Setting the Clock Frequency

Oscillator frequency is determined by an external

resistor, R_T, connected between the R_Tpin and AGND.

Resistance is calculated by:

The current limit system involves two comparators.

The MAX I_LIMITcomparator is used with a V_ILIMfixed-

voltage reference and represents the maximum

current limit allowable. This reference voltage is

temperature compensated to reflect the R_DSON

variation of the low-side MOSFET. The ADJUST I_LIMIT

comparator is used where the current limit needs to

be set lower than the V_ILIMfixed reference. The 10 µA

current source does not track the R_DSONchanges over

temperature, so change is added into the equations

for calculating the ADJUST I_LIMITcomparator

reference voltage, as is shown below. Figure 33

shows a simplified schematic of the over-current

system.

(10⁶/ f ) 135

(3)

R_T



(K)

65

where R_Tis in K and frequency (f) is in KHz.

The regulator cannot start if R_Tis left open.

Calculating the Inductor Value

Typically the inductor value is chosen based on ripple

current (I_L), which is chosen between 10 to 35% of

the maximum DC load. Regulator designs that require

fast transient response use a higher ripple-current

setting, while regulator designs that require higher

efficiency keep ripple current on the low side and

www.fairchildsemi.com

FAN2110 • Rev. 1.12

14

PW

fairly high. This could lead to operation at high load

currents, causing overheating of the regulator. For a

given R_ILIMand R_RAMPsetting, the current limit point

varies slightly in an inverse relationship with respect

to input voltage (V_IN).

RAM

COMP

+

_

VERR

PW

MAX

ILIMIT

Loop Compensation

+

_

V_CC

VILI

The loop is compensated using a feedback network

around the error amplifier. Figure 34 shows a

complete type-3 compensation network. For type-2

compensation, eliminate R3 and C3.

10µA

ADJUST

ILIMIT

ILIMTRIP

+

_

ILIM

RILIM

Figure 33. Current-Limit System Schematic

Since the I_LIMvoltage is set by a 10 µA current source

into the R_ILIMresistor, the basic equation for setting

the reference voltage is:

V_RILIM= 10µA*R_ILIM

To calculate R_ILIM

R_ILIM= V_RILIM/ 10µA

(7)

:

Figure 34. Compensation Network

(8)

Since the FAN2110 employs summing current-mode

architecture, type-2 compensation can be used for

many applications. For applications that require wide

loop bandwidth and/or use very low-ESR output

capacitors, type-3 compensation may be required.

The voltage V_RILIMis made up of two components,

V_BOT(which relates to the current through the low-

side MOSFET) and V_RMPEAK(which relates to the

peak current through the inductor). Combining those

two voltage terms results in:

R_RAMPalso provides feedforward compensation for

changes in V_IN. With a fixed R_RAMPvalue, the

modulator gain increases as V_INis reduced, which

could make it difficult to compensate the loop. For

low-input-voltage-range designs (3 V to 8 V), R_RAMP

and the compensation component values are

different compared to designs with V_INbetween 8 V

and 24 V.

(9)

R_ILIM= (V_BOT+ V_RMPEAK)/ 10µA

R_ILIM= {0.96 + (I_LOAD* R_DSON*K_T*8)} +

{D*(V_IN– 1.8)/(f_SW*0.03*10^-

3*R_RAMP)}/10 µA

(10)

where:

V_BOT= 0.96 + (I_LOAD* R_DSON*K_T*8);

V_RMPEAK= D*(V_IN– 1.8)/(f_SW*0.03*10^-3*R_RAMP);

I_LOAD= the desired maximum load current;

Recommended PCB Layout

Good PCB layout and careful attention to temperature

rise is essential for reliable operation of the regulator.

Four-layer PCB with two-ounce copper on the top and

bottom side and thermal vias connecting the layers is

recommended. Keep power traces wide and short to

minimize losses and ringing. Do not connect AGND to

PGND below the IC. Connect the AGND pin to PGND

at the output OR to the PGND plane.

R_DSON

= the nominal R_DSONof the low-side

MOSFET;

K_T= the normalized temperature coefficient for the

low-side MOSFET (on datasheet graph);

D = V_OUT/V_INduty cycle;

f_SW= Clock frequency in kHz; and

R_RAMP= chosen ramp resistor value in k.

V_IN

After 16 consecutive, pulse-by-pulse, current-limit

cycles, the fault latch is set and the regulator shuts

down. Cycling V_CCor EN restores operation after a

normal soft-start cycle (refer to the Auto-Restart

section).

SW

GND

The over-current protection fault latch is active during

V_OUT

the soft-start cycle. Use 1% resistor for R_ILIM

.

Figure 35. Recommended PCB Layout

Always use an external resistor R_ILIMto set the

current limit at the desired level. When R_ILIMis not

connected, the IC’s internal default current limit is

www.fairchildsemi.com

FAN2110 • Rev. 1.12

15

ON Semiconductor and

are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.

ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent

coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.

ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability

arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.

Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,

regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or

specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer

application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not

designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification

in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized

application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and

expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such

claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This

literature is subject to all applicable copyright laws and is not for resale in any manner.

PUBLICATION ORDERING INFORMATION

LITERATURE FULFILLMENT:

N. American Technical Support: 800−282−9855 Toll Free

USA/Canada

Europe, Middle East and Africa Technical Support:

Phone: 421 33 790 2910

Japan Customer Focus Center

Phone: 81−3−5817−1050

ON Semiconductor Website: www.onsemi.com

Order Literature: http://www.onsemi.com/orderlit

Literature Distribution Center for ON Semiconductor

19521 E. 32nd Pkwy, Aurora, Colorado 80011 USA

Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada

Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada

Email: orderlit@onsemi.com

For additional information, please contact your local

Sales Representative

www.onsemi.com

1


型号：	FAN2110MPX
厂家：	ONSEMI
描述：	-10A，24V 输入，集成同步降压稳压器信息通信管理开关稳压器
文件：	总18页 (文件大小：1035K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

FAN2110MPX [ONSEMI]

相关型号：

FAN2110MPX_12

FAN2110_12

FAN21SV04

FAN21SV04EMPX

FAN21SV04EMPX

FAN21SV04EMPX_12

FAN21SV04MPX

FAN21SV04MPX

FAN21SV04MPX_12

FAN21SV04_12

FAN21SV06

FAN21SV06EMPX