FAN6520BMX

FAN6520BMX Datasheet

FAN6520B Single Synchronous Buck PWM Controller

Part	Datasheet
FAN6520BMX	FAN6520BMX (pdf)

Related Parts	Information
FAN6520BM	FAN6520BM
FAN6520BIMX	FAN6520BIMX

PDF Datasheet Preview
FAN6520B Single Synchronous Buck PWM Controller February 2006 FAN6520B Single Synchronous Buck PWM Controller • Accepts 1.5V to 5V for VIN • Output Range 0.8V to VIN 0.8V Internal Reference Over Line Voltage and Temperature • Drives N-Channel MOSFETs • Simple Single-Loop Control Design Voltage-Mode PWM Control • Fast Transient Response High-Bandwidth Error Full 0% to 100% Duty Cycle • Small Converter Size 300kHz Fixed Frequency Oscillator Internal Soft-Start 8-Lead SOIC • Power Supplies for PC Subsystems and Peripherals • MCH, GTL, and AGP Supplies • Cable Modems, Set Top Boxes, and DSL Modems • DSP, Memory • Low-Voltage Distributed Power Supplies • ACPI Power Control • 5V Input DC-DC Regulator The FAN6520B makes simple work out of implementing a complete control and protection scheme for a DC-DC stepdown converter. Designed to drive N-channel MOSFETs in a synchronous buck topology, the FAN6520B integrates the control, output adjustment, and monitoring functions into a single 8-lead package. The FAN6520B is easy to use, employs a single feedback loop, and voltage-mode control with fast transient response. The output voltage can be precisely regulated to as low as 0.8V, with a maximum tolerance of over temperature and line voltage variations. A frequency oscillator reduces design complexity, while balancing typical application cost. The error features a 15MHz gain-bandwidth product and an 8V/µs slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty cycles range from 0% to The FAN6520B is rated for operation from 0° to +70°C with the FAN6520BI rated from to +85°C. Ordering Information Part Number FAN6520BM FAN6520BMX FAN6520BIM FAN6520BIMX Temperature Range 0°C to 70°C 0°C to 70°C to 85°C to 85°C Package SOIC-8 SOIC-8 SOIC-8 SOIC-8 Packing Rails Tape and Reel Rails Tape and Reel 2006 Fairchild Semiconductor Corporation FAN6520B Single Synchronous Buck PWM Controller BOOT HDRV GND LDRV FAN6520B SW COMP/SD FB VCC FAN6520BM 8-pin SOIC Package Pin # 1 2 3 4 5 6 7 Pin Name BOOT HDRV GND LDRV VCC FB COMP/SD Pin Function Description Bootstrap Supply Input. Provides a boosted voltage to the high-side MOSFET driver. Connect to bootstrap capacitor and diode as shown in Figure High Side Gate Drive Output. Connect to the gate of the high-side power MOSFET s . This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off. Ground. The signal and power ground for the IC. Tie this pin to the ground island/plane through the lowest impedance connection available. Connect directly to source of low-side MOSFET s . Low Side Gate Drive Output. Connect to the gate of the low-side power MOSFET s . This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the lower MOSFET has turned off. VCC. Provides bias power to the IC and the drive voltage for LDRV. Bypass with a good quality ceramic capacitor X7R or X5R as close to this pin as possible. Feedback. This pin is the inverting input of the internal error Use this pin, in combination with the COMP pin, to compensate the voltage-control feedback loop of the converter. COMP/SD. This is a multiplexed pin. During operation, the output of the error drives this pin. Pulling COMP to a level below 0.8V disables the controller. Disabling the controller causes the oscillator to stop, the HDRV and LDRV outputs to be held low, and the soft-start circuitry to re-arm. Connect a resistor between VCC and COMP/SD pin to pull up. Switch Node Input. Connect as shown in Figure The SW pin provides return for the high-side bootstrapped driver, is a sense point for the adaptive shoot-thru protection. FAN6520B Single Synchronous Buck PWM Controller 1 BOOT DBOOT CBOOT Vin = 1.5V to 5V VCC 5 CVCC RPULLUP COMP/SD 7 FAN6520B Q1 2 HDRV 8 SW Q2 4 LDRV 3 GND CBULK LOUT +VOUT COUT

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FAN6520B Single Synchronous Buck PWM Controller

February 2006

FAN6520B Single Synchronous Buck PWM Controller
• Accepts 1.5V to 5V for VIN
• Output Range 0.8V to VIN
0.8V Internal Reference Over Line Voltage and Temperature
• Drives N-Channel MOSFETs
• Simple Single-Loop Control Design Voltage-Mode PWM Control
• Fast Transient Response High-Bandwidth Error Full 0% to 100% Duty Cycle
• Small Converter Size 300kHz Fixed Frequency Oscillator Internal Soft-Start 8-Lead SOIC
• Power Supplies for PC Subsystems and Peripherals
• MCH, GTL, and AGP Supplies
• Cable Modems, Set Top Boxes, and DSL Modems
• DSP, Memory
• Low-Voltage Distributed Power Supplies
• ACPI Power Control
• 5V Input DC-DC Regulator

The FAN6520B makes simple work out of implementing a complete control and protection scheme for a DC-DC stepdown converter.

Designed to drive N-channel MOSFETs in a synchronous buck topology, the FAN6520B integrates the control, output adjustment, and monitoring functions into a single 8-lead package.

The FAN6520B is easy to use, employs a single feedback loop, and voltage-mode control with fast transient response. The output voltage can be precisely regulated to as low as 0.8V, with a maximum tolerance of over temperature and line voltage variations. A frequency oscillator reduces design complexity, while balancing typical application cost. The error features a 15MHz gain-bandwidth product and an 8V/µs slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty cycles range from 0% to

The FAN6520B is rated for operation from 0° to +70°C with the FAN6520BI rated from to +85°C.
Ordering Information

Part Number FAN6520BM FAN6520BMX FAN6520BIM FAN6520BIMX

Temperature Range 0°C to 70°C 0°C to 70°C
to 85°C to 85°C

Package SOIC-8 SOIC-8 SOIC-8 SOIC-8

Packing Rails

Tape and Reel Rails

Tape and Reel
2006 Fairchild Semiconductor Corporation

FAN6520B Single Synchronous Buck PWM Controller

BOOT HDRV

GND LDRV

FAN6520B

SW COMP/SD FB VCC

FAN6520BM 8-pin SOIC Package

Pin # 1 2 3 4 5 6 7

Pin Name BOOT HDRV GND LDRV VCC FB

COMP/SD

Pin Function Description

Bootstrap Supply Input. Provides a boosted voltage to the high-side MOSFET driver. Connect to bootstrap capacitor and diode as shown in Figure

High Side Gate Drive Output. Connect to the gate of the high-side power MOSFET s . This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off.

Ground. The signal and power ground for the IC. Tie this pin to the ground island/plane through the lowest impedance connection available. Connect directly to source of low-side MOSFET s .

Low Side Gate Drive Output. Connect to the gate of the low-side power MOSFET s . This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the lower MOSFET has turned off.

VCC. Provides bias power to the IC and the drive voltage for LDRV. Bypass with a good quality ceramic capacitor X7R or X5R as close to this pin as possible.

Feedback. This pin is the inverting input of the internal error Use this pin, in combination with the COMP pin, to compensate the voltage-control feedback loop of the converter.

COMP/SD. This is a multiplexed pin. During operation, the output of the error drives this pin. Pulling COMP to a level below 0.8V disables the controller. Disabling the controller causes the oscillator to stop, the HDRV and LDRV outputs to be held low, and the soft-start circuitry to re-arm. Connect a resistor between VCC and COMP/SD pin to pull up.

Switch Node Input. Connect as shown in Figure The SW pin provides return for the high-side bootstrapped driver, is a sense point for the adaptive shoot-thru protection.

FAN6520B Single Synchronous Buck PWM Controller
1 BOOT

DBOOT CBOOT

Vin = 1.5V to 5V

VCC 5

CVCC RPULLUP

COMP/SD 7

FAN6520B

Q1 2 HDRV
8 SW Q2
4 LDRV 3 GND

CBULK

LOUT
+VOUT COUT

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Datasheet ID: FAN6520BMX 513956