Diodes AP3581A, AP3581B, AP3581C User Manual

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Data Sheet

General Description

The1AP3581A/B/C1is1a1compact1synchronous-rect ified buck controller specifically designed to operate from 5V/12V supply and deliver high-quality output voltage as low as 0.6V (AP3581A) or 0.8V (AP3581B/C). The AP3581A/B/C operates at fixed frequency of 300kHz (AP3581A/B) or 200kHz (AP3581C) and provides an optimal level of integration to reduce size and cost of the power supply.

This controller integrates internal MOSFET drivers that support 12V+12V bootstrapped voltage for highefficiency power conversion. The bootstrap diode is built-in to simplify the circuit design and minimize external part count.

This controller provides single feedback loop, voltage-mode control with fast transient response. The error amplifier features a 10MHz gain-bandwidth product and 6V/µs slew rate which enables high converter bandwidth for fast transient performance.

Other features include internal soft-start, under voltage protection, over current protection and shutdown function. With afore-mentioned functions, this part provides customers a compact, high efficiency, well-protected and cost-effective solutions.

The AP3581A/B/C is available in PSOP-8 package.

Figure 1. Package Type of AP3581A/B/C

Features

• Supply Voltage: 5V/12V

• V

• 0.6V/0.8V to 80% of V

• Internal Reference: 0.6V/0.8V

• Simple Single-loop Control

• Voltage-mode PWM Control

• Duty Cycle: 0% to 80%

• Fast Transient Response

• 10MHz High-bandwidth Error Amplifier with

• Fixed Oscillator Frequency: 300kHz/200kHz

• Lossless, Programmable Over Current Protection

• Start-up into Pre-biased Output

• Built-in Thermal Shutdown

• Built-in Soft-start

• Over Current/Voltage Protection

• Under Voltage Protection

• Integrated Boot Diode

Input Range: 3.0V to 13.2V

IN

6V/µs Slew Rate

(Uses Lower MOSFET R

Output Range

)

DS(ON)

Applications

• Power Supplies for Microprocessors/Peripherals

PCs, Embedded Controllers, Memory Supplies

•

• DSP and Core Communications Processor

Supplies

• Subsystem Power Supplies

• PCI, AGP, Graphics Cards, Digital TV

• SSTL-2 and DDR/2/3 SDRAM Bus Termination

Supply

• Cable Modems, Set Top Boxes, and DSL

Modems

• Industrial Power Supplies and General Purpose

Supplies

• 5V/12V Input DC-DC Regulators

• Low-voltage Distributed Power Supplies

PSOP-8

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p

Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Pin Configuration

MP Package

(PSOP-8)

1

2

3

4

Figure 2. Pin Configuration of AP3581A/B/C (Top View)

8

7

6

5

Pin Description

Pin Number Pin Name Function

Bootstrap pin. Connect a bootstrap capacitor (Typically from

1 BOOT

2 UGATE

3 OPS

4 LGATE

5 VCC

6 FB

7 COMP/EN

8 PHASE

9 GND

0.1µF to 0.47µF) from this pin to PHASE pin to create a BOOT voltage suitable to drive a standard N-Channel MOSFET

Upper-gate drive pin. Connect this pin to the upper MOSFET gate

roviding the gate drive. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has been turned off

Over-current setting pin. Connecting a resistor (R OPS and GND to set the over-current trigger point Lower-gate drive pin. Connect LGATE to the lower MOSFET gate providing the gate drive for the lower MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the lower MOSFET has turned off Bias supply pin. Provides a 5V or 12V bias supply for the chip from this pin. The pin should be bypassed with a capacitor to GND Feedback pin. This pin is the inverting input of the internal error amplifier. Use FB pin, in combination with the COMP pin, to compensate the voltage control feedback loop of the converter. A resistor divider from output to GND is used to set the output voltage Compensation and disable pin, this pin is the output of the error amplifier. Pull COMP pin low will shut down the IC PHASE pin. This pin connects to the source of the upper MOSFET and the drain of the lower MOSFET. This pin is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off Exposed pad as ground pin. Represents the signal and power ground for the IC. Tie this pin to the ground island/plane through the lowest impedance connection available

) between

OCSET

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Functional Block Diagram

Figure 3. Functional Block Diagram of AP3581A/B/C

Ordering Information

AP3581 A A -

Circuit Type A:AP3581A B:AP3581B C:AP3581C

Package

PSOP-8 -40 to 85°C

BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green.

Oct. 2011 Rev. 1. 0 BCD Semiconductor Manufacturing Limited

MP: PSOP-8

Temperature

Range

Part Number Marking ID Packing Type

AP3581AMP-G1 3581AMP-G1 Tube

AP3581AMPTR-G1 3581AMP-G1 Tape & Reel

AP3581BMP-G1 3581BMP-G1 Tube

AP3581BMPTR-G1 3581BMP-G1 Tape & Reel

AP3581CMP-G1 3581CMP-G1 Tube

AP3581CMPTR-G1 3581CMP-G1 Tape & Reel

G1: Green

Blank: Tube TR: Tape & Reel

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Absolute Maximum Ratings (Note 1)

Parameter Symbol Value Unit

Supply Voltage VCC -0.3 to 15 V

BOOT Voltage V

Voltage from UGATE to PHASE

Voltage from PHASE, LGATE Pin to GND

Voltage on Other Separate Pin

Thermal Resistance

Operating Junction Temperature

Storage Temperature

Lead Temperature (Soldering, 10 sec)

ESD (Human Body Model) (Note 2) 2000 V

ESD (Machine Model) (Note 2) 200 V

-0.3 to V

BOOT

V

UGATE

V

,

PHASE

V

LGATE

θ

JA

T

J

T

STG

T

LEAD

+15 V

PHASE

-0.3 to 15 V

-1 to 15 V

-0.3 to 6 V

50 ºC/W

-40 to 125 ºC

-65 to 150 ºC

260 ºC

Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability. Note 2: Devices are ESD sensitive. Handling precaution recommended.

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Supply Input Voltage VCC 4.5 13.2 V

Operating Junction Temperature Range TJ -40 125

Operating Ambient Temperature TA -40 85

°C

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Electrical Characteristics

VCC=12V, TA=25°C, unless otherwise specified.

Parameter Symbol Conditions Min Typ Max Unit

SUPPLY INPUT

Supply Voltage VCC 4.5 13.2 V

UGATE and LGATE

Supply Current ICC

Quiescent Supply Current I

CC_Q

Power Input Voltage VIN 3.0 13.2 V

Pin Open; VCC=12V, Switching

V

FB=VREF

No Switching

+0.1V,

5 mA

4 mA

POWER ON RESET

VCC Rising Threshold V

VCC Threshold Hysteresis V

VCC Rising 4.0 4.2 4.4 V

POR

500 mV

POR_HYS

OSCILLATOR

AP3581A/B 270 300 330

Oscillator Frequency f

Ramp Amplitude ∆V

OSC

AP3581C 180 200 220

VCC=12V 1.8 V

kHz

ERROR AMPLIFIER

Open Loop DC Gain (Note 3) G

55 70 dB

DC_OL

Gain Bandwidth (Note 3) GBW 10 MHz

Slew Rate (Note 3) SR 3 6

Transconductance 800 1100

Output Source Current VFB<V

Output Sink Current VFB>V

80 120

REF

80 120

REF

V/µs

µA/V

µA

PWM CONTROLLER GATE DRIVERS

Upper Gate Source Current I

Upper Gate Sink Current I

Upper Gate Sink Resistance R

Lower Gate Source Current I

Lower Gate Sink Current I

Lower Gate Sink Resistance R

PHASE Falling to LGATE Rising Delay

UG_SRC

UG_SNK

UGATE

LG_SRC

LG_SNK

LGATE

V

BOOT-VPHASE

V

BOOT-VUGATE

V

BOOT-VPHASE

V

BOOT-VUGATE

50mA Sink Current, V

BOOT-VPHASE

VCC-V

V

LGATE

50mA Sink Current, V

=12V

CC

V

PHASE

V

LGATE

=12V,

=6V

=12V,

=6V

=12V

=6V -1 A

LGATE

-1 A

1.5 A

1.6 3.2

Ω

=6V 1.5 A

<1.2V to >1.2V

1 2

50 ns

Ω

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Electrical Characteristics (Continued)

VCC=12V, T

=25ºC, unless otherwise specified.

A

Parameter Symbol Conditions Min Typ Max Unit

LGATE Falling to UGATE Rising Delay

Minimum Duty Cycle 0 %

Maximum Duty Cycle 75 80 85 %

REFERENCE VOLT AGE

Feedback Voltage VFB

PROTECTION

Under Voltage Protection V

Over Current Source I

FB_UVP

OPS

Soft-start Interval tSS

Enable Threshold V

Thermal Shutdown T

Thermal Shutdown Hysteresis T

COMP/EN

OTSD

HYS

V

<1.2V to

LGATE

(V

UGATE-VPHASE

)>1.2V

50 ns

AP3581A 0.591 0.6 0.609 V

AP3581B/C 0.788 0.8 0.812 V

0.3 0.4 0.5 V

30 40 50

µA

AP3581A 2.0

AP3581B 2.7

ms

AP3581C 3.6

0.25 0.30 0.35 V

160 ºC

20 ºC

Note 3: Not tested, guaranteed by design.

Typical Performance Characteristics

0.5

0.4

0.3

V

=1.2V, I

0.2

0.1

0.0

-0.1

-0.2

-0.3

Output Voltage Variation (%)

-0.4

-0.5

OUT

4 5 6 7 8 9 1011121314

OUT

=5A

Input Voltage (V)

0.2

0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

Output Voltage Variation (%)

-0.6

-0.7 0 2 4 6 8 10 12 14 16 18 20

VIN=12V,V

Output Current (A)

OUT

=1.2V

Figure 4. Line Regulation Figure 5. Load Regulation

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Typical Performance Characteristics (Continued)

360 350 340 330 320 310 300 290 280 270

Switching Frequency (kHz)

260 250 240

-50 -25 0 25 50 75 100 125 150

Temperature (oC)

For AP3581A

360 350 340 330 320 310 300 290 280 270

Switching Frequency (kHz)

260 250 240

4 5 6 7 8 9 1011121314

For AP3581A

Input Voltage (V)

Figure 6. Switching Frequency vs. Temperature Figure 7. Switching Frequency vs. Input Voltage

0.70

0.68

0.66

0.64

0.62

0.60

0.58

0.56

Feedback Voltage (V)

0.54

0.52

0.50

-50 -25 0 25 50 75 100 125 150

For AP3581A

Temperature (°C)

0.70

0.68

0.66

0.64

0.62

0.60

0.58

0.56

Feedback Voltage (V)

0.54

0.52

0.50 4 5 6 7 8 9 10 11 12 13 14

For AP3581A

Input Voltage (V)

Figure 8. Feedback Voltage vs. Temperature Figure 9. Feedback Voltage vs. Input Voltage

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Typical Performance Characteristics (Continued)

VIN

10V/div

V

OUT

0.5V/div

V 10V/div

(V

V

COMP

LGATE

Figure 10. Power-on Waveform Figure 11. Power-off Waveform

Time 1ms/div

=12V, V

IN

OUT

=1.2V, I

=0A) (VIN=12V, V

OUT

V

10V/div

V

OUT

0.5V/div V

PHASE

10V/div

I

10A/div

IN

L

OUT

s/div

=1.2V, I

=20A)

OUT

Time 200

10V/div

0.5V/div

10A/div

V

OUT

COMP

I

IN

L

Time 1ms/div

Figure 12. Enable Waveform

(VIN=12V, V

OUT

=1.2V, I

OUT

V

PHASE

10V/div

V

OUT

0.5V/div V

COMP

0.5V/div

I

L

10A/div

Time 20

=0A) (VIN=12V, V

Figure 13. Disable Waveform

OUT

s/div

=1.2V, I

OUT

=20A)

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µ

Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Typical Performance Characteristics (Continued)

V

PHASE

5V/div

V

OUT_AC

200mV/div

V

200mV/div

V

PHASE

5V/div

OUT_AC

I

OUT

5A/div

OUT

10A/div

Time 10

s/div

Time 10

s/div

Figure 14. Load Transient Response (VIN=12V, V

OUT

=1.2V, I

=0A to 10A) (VIN=12V, V

OUT

Figure 15. Load Transient Response

OUT

=1.2V, I

=0A to 20A)

OUT

V

UGATE-PHASE

2V/div

V

UGATE-PHASE

2V/div

V

PHASE

2V/div

LGATE

2V/div

V

LGATE

2V/div

Figure 16. UGATE Turn Off Waveforms Figure 17. UGATE Turn On Waveforms

(VCC=VIN=12V, V

Time 40ns/div

=1.2V, I

OUT

=20A) (VCC=VIN=12V, V

OUT

V

PHASE

2V/div

Time 40ns/div

OUT

=1.2V, I

OUT

=20A)

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µ

Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Typical Performance Characteristics (Continued)

V

OUT

1V/div

V

COMP

0.5V/div

V

PHASE

10V/div

I

L

10A/div

VFB

1V/div

V

LGATE

10V/div

V

UGATE

20V/div

I

10A/div

L

Time 10ms/div

Time 80

s/div

Figure 18. Over Current Protection Figure 19. Over Voltage Protection

(VIN=12V, V

=1.2V to 0V, I

OUT

=0A) (VIN=12V, V

OUT

=1.2V, I

OUT

=20A)

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Typical Application

Figure 20. Typical Application Circuit of AP3581A/B/C

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Data Sheet

Single Phase Synchronous Buck PWM Controller AP3581A/B/C

Mechanical Dimensions

PSOP-8 Unit: mm(inch)

3.202(0.126)

3.402(0.134)

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