Fairchild FAN2110 service manual

FAN2110 — TinyBuck™

3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

September 2011

Features



Wide Input Voltage Range: 3V-24V

 Wide Output Voltage Range: 0.8V to 80% V

IN

 10A Output Current  1% Reference Accuracy Over Temperature  Over 93% Peak Efficiency  Programmable Frequency Operation: 200KHz to

600KHz

 Fully Synchronous Operation with Integrated

Schottky Diode on Low-Side MOSFET Boosts Efficiency

 Internal Bootstrap Diode  Power-Good Signal  Starts up on Pre-Bias Outputs

 Accepts Ceramic Capacitors on Output  External Compensation for Flexible Design  Programmable Current Limit  Under-Voltage, Over-Voltage, and Thermal

Shutdown Protections

 Internal Soft-Start  5x6mm, 25-Pin, 3-Pad MLP Package

Applications

Servers & Telecom

  Graphics Cards & Displays

 Computing Systems  Point-of-Load Regulation  Set-Top Boxes & Game Consoles

Description

The FAN2110 TinyBuck™ is a highly efficient, small footprint, constant frequency, 10A integrated synchronous Buck regulator.

The FAN2110 contains both synchronous MOSFETs and a controller/driver with optimized interconnects in one package, which enables designers to solve highcurrent 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.

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.

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.

Fairchild’s advanced BiCMOS power process, combined with low-R efficient MLP package, provide the ability to dissipate high power in a small package.

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-ofload applications.

internal MOSFETs and a thermally

DS(ON)

Related Application Notes

TinyCalc™ Calculator Design Tool AN-8022 — TinyCalc™ Calculator User Guide

Ordering Information

Operating

Part Number

FAN2110MPX -10°C to 85°C Molded Leadless Package (MLP) 5x6mm Tape and Reel

FAN2110EMPX -40°C to 85°C Molded Leadless Package (MLP) 5x6mm Tape and Reel

Temperature Range Package

Packing

Method

Typical Application

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

IN

C

HF

Power

Enable

Good

P2

+5V

C

IN

C2

R2

C4

R

RAMP

R

ILIM

C1

R

T

VCC

RAMP

PGOOD

EN

ILIM

R(T)

COMP

AGND

15

25 13 14 17 18

20

16

Boot

Diode

PWM

+

DRIVER

Q1

Q2

POWER

MOSFETS

1

P1

P3

24

19

BOOT

SW

PGND

NC

FB

C

BOOT

OUT

L

C

OUT

R1

R

BIAS

C3

R3

Figure 1. Typical Application Diagram

Block Diagram

Figure 2. Block Diagram

Pin Configuration

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

Figure 3. MLP 5x6mm Pin Configuration (Bottom View)

Pin Definitions

Pin # Name Description

P1, 6-12 SW

P2, 2-5 VIN

P3, 21-23 PGND

1 BOOT

13 PGOOD

14 EN

15 VCC

16 AGND

17 ILIM

18 R(T) 19 FB 20 COMP 24 NC 25 RAMP

Switching Node. Junction of high-side and low-side MOSFETs. Power Conversion Input Voltage. Connect to the main input power source. Power Ground. Power return and Q2 source. High-Side Drive BOOT Voltage. Connect through capacitor (C

an internal synchronous bootstrap diode to recharge the capacitor on this pin to VCC when 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.

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 > 2.2µF X5R / X7R capacitor.

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 limit trip threshold lower than the internal default setting.

Oscillator Frequency. A resistor (R frequency.

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.

No Connect. This pin is not used. Ramp Amplitude. A resistor (R

and provides voltage feedforward functionality.

) to SW. The IC includes

BOOT

) from this pin to AGND can be used to program the current-

ILIM

) from this pin to AGND sets the PWM switching

T

) connected from this pin to VIN sets the ramp amplitude

RAMP

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

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 Conditions Min. Max. Unit

VIN to PGND 28 V

VCC to AGND AGND=PGND 6 V

BOOT to PGND 35 V

BOOT to SW -0.5 6.0 V

SW to PGND

All other pins -0.3 VCC+0.3 V

ESD

Continuous -0.5 24.0 V Transient (t < 20ns, f < 600KHz) -5 30 V

Human Body Model, JEDEC JESD22-A114 2.0 Charged Device Model, JEDEC JESD22-C101 2.5

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 Parameter Conditions Min. Typ. Max. Unit

VCC Bias Voltage VCC to AGND 4.5 5.0 5.5 V

VIN Supply Voltage VIN to PGND 3 24 V

TA Ambient Temperature

TJ Junction Temperature +125 °C

fSW Switching Frequency 200 600 kHz

FAN2110MPX -10 +85 °C FAN2110EMPX -40 +85 °C

Thermal Information

Symbol Parameter Min. Typ. Max. Unit

T

Storage Temperature -65 +150 °C

STG

TL Lead Soldering Temperature, 10 Seconds +300 °C

P1 (Q2) 4 °C/W



JC



J-PCB

PD Power Dissipation, TA=25°C

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.

Thermal Resistance: Junction-to-Case

Thermal Resistance: Junction-to-Mounting Surface

(1)

2.8 W

P2 (Q1) 7 °C/W P3 4 °C/W

(1)

35 °C/W

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

Electrical Specifications

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

Symbol Parameter Conditions Min. Typ. Max. Unit

Power Supplies

SW=Open, V f

=600KHz

ICC VCC Current

SW

Shutdown: EN=0, VCC=5V 7 10 µA

V

VCC UVLO Threshold

UVLO

Rising VCC 4.1 4.3 4.5 V Hysteresis 300 mV

Oscillator

R

=50K to GND

fSW Frequency

T

RT=24K to GND

t

Minimum On-Time

ONmin

V

Ramp Amplitude, Peak-to-Peak

RAMP

t

Minimum Off-Time

OFFmin

(2)

50 65 ns

, 1.8V

16V

IN

=200K

R

(2)

100 150 ns

RAMP

Reference

VFB

Reference Voltage (see Figure 4 for

Temperature Coefficient)

FAN2110MPX, 25°C 794 800 806 mV FAN2110EMPX, 25°C 795 800 805 mV

Error Amplifier

G DC Gain

GBW Gain Bandwidth Product

V

Output Voltage

COMP

I

Output Current, Sourcing VCC=5V, V

SINK

I

Output Current, Sinking VCC=5V, V

SOURCE

I

FB Bias Current VFB=0.8V, 25°C -850 -650 -450 nA

BIAS

(2)

12 15 MHz

(2)

0.4 3.2 V

=5V

V

CC

Protection and Shutdown

R

=182 K, 25°C, fSW=500KHz,

I

LIM

I

ILIM

T T V

V

UVSD

V

FLT_HYS

Current Limit (see Circuit

Description)

I

Over-Temperature Shutdown

TSD

Over-Temperature Hysteresis

HYS

Over-Voltage Threshold 2 Consecutive Clock Cycles

OVP

Current VCC=5V, 25°C -11 -10 -9 µA

LIM

(2)

+30 °C

Under-Voltage Shutdown 16 Consecutive Clock Cycles

Fault Discharge Threshold Measured at FB Pin 250 mV

FLT

Fault Discharge Hysteresis Measured at FB Pin (VFB ~500mV) 250 mV

ILIM

=1.5V, R

V

OUT

16 Consecutive Clock Cycles

Internal IC Temperature

Soft-Start

tSS V tEN Fault Enable/SSOK (T1.0)

to Regulation (T0.8)

OUT

f

=500KHz

(2)

6.7 ms

SW

=0.7V, VCC=5V,

FB

8 12 mA

255 300 345 KHz 540 600 660 KHz

, RT=30K,

OUT

0.53 V

80 85 dB

=2.2V 1.5 2.2 mA

COMP

=1.2V 0.8 1.2 mA

COMP

RAMP

=243K

(3)

12 14 16 A

+155 °C

(3)

110 115 121 %V

(3)

68 73 78 %V

OUT

5.3 ms

Continued on the following page…

FAN2110 — TinyBuck™, 3-24V Input, 10A, High-Efficiency, Integrated Synchronous Buck Regulator

Electrical Specifications (Continued)

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

Symbol Parameter Conditions Min. Typ. Max. Unit

Control Functions

VEN EN Threshold, Rising VCC=5V 1.35 2.00 V

V

Notes:

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

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

EN Hysteresis VCC=5V 250 mV

EN_HYS

REN EN Pull-Up Resistance VCC=5V 800

I

EN Discharge Current Auto-Restart Mode, VCC=5V 1 µA

EN_DISC

R

FB OK Drive Resistance 800

FBok

PGTH_LO

PGOOD LOW Threshold

PGTH_UP

V

PGOOD Output Low I

PG_LO

I

PGOOD Leakage Current V

PG_LK

FB < V Cycles

FB > V Cycles

OUT

PGOOD

, 2 Consecutive Clock

REF

(3)

, 2 Consecutive Clock

REF

(3)

-14 -11 -8

+7 +10 +13.5

< 2mA 0.4 V

=5V 0.2 1.0 µA

%V

K



REF

Fairchild FAN2110 service manual

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