Sony TA3020 Service Manual

TA3020

Tripath Technology, Inc. - Technical Information

STEREO 300W (4Ω) CLASS-T DIGITAL AUDIO AMPLIFIER DRIVER

TM

USING DIGITAL POWER PROCESSING (DPP

Technical Information Revision 3.0 – September 2003

GENERAL DESCRIPTION

The TA3020 is a two-channel, 300W (4Ω) per channel Amplifier Driver IC that uses Tripath’s proprietary Digital Power Processing (DPP power efficiency of Class-D amplifiers.

APPLICATIONS

 Audio/Video Amplifiers & Receivers  Pro-audio Amplifiers  Automobile Power Amplifiers  Subwoofer Amplifiers

BENEFITS

 Reduced system cost with smaller/less

expensive power supply and heat sink

 Signal fidelity equal to high quality Class-

AB amplifiers

 High dynamic range compatible with

digital media such as CD and DVD

TM

) technology. Class-T amplifiers offer both the audio fidelity of Class-AB and the

FEATURES

 Class-T architecture  Proprietary Digital Power Processing technology  “Audiophile” Sound Quality

 0.02% THD+N @ 50W, 8Ω  0.03% IHF-IM @ 30W, 8Ω

 High Efficiency

 95% @ 150W @ 8Ω  90% @ 275W @ 4Ω

 Supports wide range of output power levels

 Up to 300W/channel (4Ω), single-ended outputs  Up to 1000W (4Ω), bridged outputs

 Output over-current protection  Over- and under-voltage protection  Thermally Enhanced 48-pin DIP (dual-inline

package)

) TECHNOLOGY

TYPICAL PERFORMANCE

THD+N versus Output Power versus Supply Voltage

10

f = 1kHz

5

BBM = 80nS BW = 22Hz - 22kHz

2

1

0.5

0.2

THD+N (%)

0.1

0.05

0.02

0.01 1 5002 5 10 20 50 100 200

Output Power (W)

RL = 4

Ω

39V

45V

54V

1 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

Absolute Maximum Ratings

(Note 1)

SYMBOL PARAMETER Value UNITS

VPP, VNN Supply Voltage +/- 70 V

V5 Positive 5 V Bias Supply

VN10 Voltage for FET drive VNN+13 V

T

STORE

T

A

TJ Junction Temperature 150º C

ESDHB ESD Susceptibility – Human Body Model (Note 3)

ESDMM ESD Susceptibility – Machine Model (Note 4)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 2: This is a target specification. Characterization is still needed to validate this temperature range. Note 3: Human body model, 100pF discharged through a 1.5KΩ resistor. Note 4: Machine model, 220pF – 240pF discharged through all pins.

Voltage at Input Pins (pins 12-16, 18, 19-26, 29-33, 37)

Storage Temperature Range -55º to 150º C

Operating Free-air Temperature Range (Note 2) -40º to 85º C

All pins

See the table below for Operating Conditions.

-0.3V to (V5+0.3V)

6

2000

200

V

Operating Conditions

(Note 5)

SYMBOL PARAMETER MIN. TYP. MAX. UNITS

VPP, VNN Supply Voltage +/- 15 +/-45 +/- 65 V

V5 Positive 5 V Bias Supply 4.5 5 5.5 V

VN10 Voltage for FET drive (Volts above VNN) 9 10 12 V

Note 5: Recommended Operating Conditions indicate conditions for which the device is functional.

See Electrical Characteristics for guaranteed specific performance limits.

2 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

Electrical Characteristics

TA = 25 °C. See Application/Test Circuit on page 7. Unless otherwise noted, the supply voltage is VPP=|VNN|=45V.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS

I

q

I

MUTE

VIH High-level input voltage (MUTE) 3.5 V

VIL Low-level input voltage (MUTE) 1.0 V

VOH High-level output voltage (HMUTE) I

VOL Low-level output voltage (HMUTE) I

V

OFFSET

IOC Over Current Sense Voltage

I

VPPSENSE

V

VPPSENSE

I

VNNSENSE

V

VNNSENSE

Note 6: Minimum and maximum limits are guaranteed but may not be 100% tested. Note 7: These supply voltages are calculated using the I Characteristics table. The typical voltage values shown are calculated using a R value of 422kohm without any tolerance variation. The minimum and maximum voltage limits shown include either a +1% or –1% (+1% for Over-voltage turn on and Under-voltage turn off, -1% for Over-voltage turn off and Under-voltage turn on) variation of R values. These voltage specifications are examples to show both typical and worst case voltage ranges for a given R Application Information section for a more detailed description of how to calculate the over and under voltage

trip voltages for a given resistor value.

Note 8: The fact that the over-voltage turn on specifications exceed the absolute maximum of +/-70V for the TA3020 does not imply that the part will work at these elevated supply voltages. It also does not imply that the TA3020 is tested or guaranteed at these supply voltages. The supply voltages are simply a calculation based on the process spread of the I currents (see note 7). The supply voltage must be maintained below the absolute maximum of +/-70V or permanent damage to the TA3020 may occur.

Quiescent Current (No load, BBM0=1,BBM1=0, Mute = 0V)

Mute Supply Current (No load, Mute = 5V)

Output Offset Voltage No Load, MUTE = Logic low

Threshold

VPPSENSE Threshold Currents Over-voltage turn on (muted)

Threshold Voltages with

R

VPPSENSE

= 422KΩ

(Note 7,8)

VNNSENSE Threshold Currents Over-voltage turn on (muted)

Threshold Voltages with

R

VNNSENSE

= 392KΩ

(Note 7,8)

VPPSENSE

and R

VNNSENSE

(Note 6)

VPP = +45V VNN = -45V V5 = 5V VN10 = 10V VPP = +45V VNN = -45V V5 = 5V VN10 = 10V

= 3mA 4.0 V

OH

= 3mA 0.5 V

OL

90

90 45

200

1

20

1

60

250

25

mA mA mA mA mA mA mA mA

-750 750 mV

0.1% R

FBA

, R

FBB

, R

resistors

FBC

TBD 0.85 .97 1.09 V

Over-voltage turn off (mute off) Under-voltage turn off (mute off) Under-voltage turn on (muted)

Over-voltage turn on (muted) Over-voltage turn off (mute off) Under-voltage turn off (mute off) Under-voltage turn on (muted)

Over-voltage turn off (mute off) Under-voltage turn off (mute off) Under-voltage turn on (muted)

Over-voltage turn on (muted) Over-voltage turn off (mute off) Under-voltage turn off (mute off) Under-voltage turn on (muted)

138

62

57.6

25.9

152

65

-59.0

-25.2

162 154

79 72

68.4

65.0

33.3

30.4 174 169

86 77

-68.2

-66.2

-33.7

-30.2

178

87

75.8

37.1

191

95

-75.6

-37.6

A

µ

A

µ

A

µ

A

µ

V V V V

A

µ

A

µ

A

µ

A

µ

V V V V

and I

VNNSENSE

off the nominal 422kohm and 392kohm

VPPSENSE

or R

resistor values of 422kohm and 392kohm. Please refer to the

VPPSENSE

values shown in the Electrical

and I

VPPSENSE

VNNSENSE

and R

VNNSENSE

3 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

Performance Characteristics – Single Ended

TA = 25 °C. Unless otherwise noted, the supply voltage is VPP=|VNN|=45V, the input frequency is 1kHz and the measurement bandwidth is 20kHz. See Application/Test Circuit.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS

P

Output Power

OUT

(continuous RMS/Channel)

THD + N Total Harmonic Distortion Plus

Noise

IHF-IM IHF Intermodulation Distortion

SNR Signal-to-Noise Ratio

CS Channel Separation

η

Power Efficiency

AV Amplifier Gain

THD+N = 0.1%, R R THD+N = 1%, R R

= 50W/Channel, RL = 8Ω

P

OUT

19kHz, 20kHz, 1:1 (IHF), R

= 30W/Channel

P

OUT

A Weighted, R

= 275W/Channel

P

OUT

0dBr = 30W, R

= 150W/Channel, RL = 8Ω

P

OUT

P

= 10W/Channel, RL = 4Ω

OUT

= 8Ω

L

= 4Ω

L

= 8Ω

L

= 4Ω

L

= 4Ω,

L

= 8Ω, f = 1kHz

L

See Application / Test Circuit

A

Channel to Channel Gain Error

VERROR

P

= 10W/Channel, RL = 4Ω

OUT

See Application / Test Circuit

e

Output Noise Voltage A Weighted, no signal, input shorted,

NOUT

= 8Ω

L

100 190 120 220

W

W W W

0.02 %

0.03 %

102 dB

97 dB

95 %

10.7 V/V

0.5 dB

260

V

µ

DC offset nulled to zero

TA3020 Pinout

VN10

LO2

LO2COM

HO2COM

HO2

OCS2LN

OCS2LP

OCS2HP

OCS2HN

VBOOT2

NC

OCR2

FBKOUT1 FBKGND1

HMUTE

FBKOUT2

DCOMP

FBKGND2

BIASCAP

INV2

OAOUT2

BBM0 BBM1

MUTE

48-pin Dip

(Top View)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15 16

17

18 19

20

21

22 23

24

48

LO1

47

LO1COM

46

HO1COM

45

HO1

44

OCS1HN

43

OCS1HP

42

OCS1LP

41

OCS1LN

40

VBOOT1

39

VNN

38

NC

37

OCR1

36

NC

35

V5

34

AGND

33

OCR1

32

REF

31

OCR2

30

VNNSENSE

29

VPPSENSE

28

AGND

27

V5

26

OAOUT1

25

INV1

4 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

Pin Description

1 VN10 “Floating” supply input for the FET drive circuitry. This voltage must be stable

2,48 LO2, LO1 Low side gate drive output (Channel 2 & 1) 3,47 LO2COM, LO1COM Kelvin connection to source of low-side transistor (Channel 2 & 1) 4,46 HO2COM, HO1COM Kelvin connection to source of high-side transistor (Channel 2 & 1) 5,45 HO2, HO1 High side gate drive output (Channel 2 & 1)

6, 7 OCS2LN, OCS2LP Over Current Sense inputs, Channel 2 low-side 8, 9 OCS2HP, OCS2HN Over Current Sense inputs, Channel 2 high-side

10, 40 VBOOT2, VBOOT1 Bootstrapped voltage to supply drive to gate of high-side FET

12, 31 OCR2 Over-current threshold adjustment (Channel 2) 13, 16 FBKOUT1, FBKOUT2 Switching feedback (Channels 1 & 2) 14, 18 FBKGND1, FBKGND2 Ground Kelvin feedback (Channels 1 & 2)

15 HMUTE Logic Output. A logic high indicates both amplifiers are muted, due to the

17 DCOMP Internal mode selection. This pin must be grounded for proper device

19 BIASCAP Bandgap reference times two (typically 2.5VDC). Used to set the common

20, 25 INV2, INV1 Inverting inputs of Input Stage op amps. (Channels 2 & 1) 21, 26 OAOUT2, OAOUT1 Outputs of Input Stage op amps. (Channels 2 & 1) 22, 23 BBM0, BBM1 Break-before-make timing control to prevent shoot-through in the output FETs.

24 MUTE Logic input. A logic high puts the amplifier in mute mode. Ground pin if not

27, 35 V5 5V power supply input.

28,34 AGND Analog ground.

29 VPPSENSE Positive supply voltage sense input. This pin is used for both over and

30 VNNSENSE Negative supply voltage sense input. This pin is used for both over and under

32 REF Used to set internal bias currents. The pin voltage is typically 1.1V.

33, 37 OCR1 Over-current threshold adjustment (Channel 1)

39 VNN Negative supply voltage. 41, 42 OCS1LN, OCS1LP Over Current Sense inputs, Channel 1 low-side 43, 44 OCS1HP, OCS1HN Over Current Sense inputs, Channel 1 high-side

11, 36,

38

Function

and referenced to VNN.

(Channel 2 & 1)

mute pin state, or a “fault” such as an overcurrent, undervoltage, or overvoltage condition.

operation.

mode voltage for the input op amps. This pin is not capable of driving external circuitry.

used. Please refer to the section, Mute Control, in the Application Information.

under voltage sensing for the VPP supply.

voltage sensing for the VNN supply.

NC Not connected (bonded) internally. To minimize coupling between pins, tie

these pins to AGND (pin34).

Description

5 TA3020 – KL Rev. 3.0/09.03

Application/Test Circuit

OAOUT1

C

I

3.3uF +

V5 (Pin 27)

R

OFA

10K

Offset Trim

Circ uit

Ω

R

F

20K

Ω

R

I

49.9K

Ω

R

OFB

499K

Ω

A GND (Pin 28)

C

A

0.1uF

(Pin 28)

5V

(Pin 28)

R

REF

8.25K

1%

Ω,

INV 1

R

OFB

499K

C

OF

0.1uF

BIA SCAP

MUTE

REF1

Ω

Tripath Technology, Inc. - Technical Information

TA3020

OCS1HP

43

R

0.01

1W

DG MUR120

RG 5.6Ω, 1W

DG MUR120

RG 5.6Ω, 1W

0.01

R

OCR

20K

C

FB

A GND (Pin 28)

Ω,

V5 (Pin 27)

Ω

*R

1.07K

Q

R

1W

R

FBA

1K

FBB

VN10

OCS1HN

44

40

VBOOT1

DS MUR120

45

HO1

HO1CO M

46

DS MUR120

48

LO1

47

LO1COM

42

OCS1LP

41

OCS1LN

37

OCR1 OCR1

33

220pF

FBKOUT1

13 14

FBKGND1

15

HMUTE

C

OCR

AGND

(Pin 28)

150pF

26

V5

25

-

+

AGND

Process ing

&

Modulation

2.5V

200K

19

Ω

V5

24

32

S

O

Q

O

S

Ω

C

S

0.1uF

DO MUR120

C

HBR

0.1uF

R 16Ω, 1W

D

MUR120

O

R

FBA

1K

Ω

*R

FBB

1.07K

Ω

SN

C

S

0.1uF

*R

13.3K

C

HBR

33uF

C

SN

220pF

FBC

D

MUR120

B

R

B

C

B

0.1uF

+

L

O

10uH

Ω

*R

FBC

13.3K

VN10

250

Ω

+

C

BAUX

47uF

C

O

0.22uF

+

C

S

330uF

C

S

330uF

VPP

VNN

R

Z

20

Ω,

C

Z

0.22uF

2W

R

4Ω or 8

L

Ω

(Pin 28)

C

I

3.3uF +

V5 (Pin 27)

R

OFA

10K

Offset Trim

Circ uit

*R

VNN

*R

VPP

*R

V5

*R

V5

R

I

49.9K

Ω

A GND (Pin 28)

5V

VNN1

392KΩ, 1%

VPP1

422KΩ, 1%

VNN2

1.35M

VPP1

422K

20K

Ω

R

OFB

499K

Ω,

Ω

R

Ω

0.1uF

1%

, 1%

F

Ω

C

OAOUT2

INV 2

R

OFB

499K

C

OF

0.1uF

BBM0

BBM1

DCOMP

S

21

V5

20

-

+

AGND

Ω

Process ing

&

Modulation

22

23

17

27

V5

28

AGND

35

V5

34

AGND

30

VNNSENSE

29

V PPSENS E

11

NC

F. BEA D

* The values of thes e components must be adjusted based on supply voltage range. See Application Information.

Analog Ground

Pow e r Ground

VN10

VNN

NC

OCS2HP

8

OCS2HN

9

10

VBOOT2

DS MUR120

5

HO2

4

HO2CO M

DS MUR120

2

LO2

LO2COM

3

OCS2LP

7

6

OCS2LN

12

OCR2 OCR2

31

220pF

16

FBKOUT2

18

FBKGND2

1

39

38

36

C

OCR

AGND

VNN

(Pin 28)

150pF

C

SW

0.1uF,35V

VNN

0.01

DG MUR120

RG 5.6Ω, 1W

DG MUR120

RG 5.6Ω, 1W

0.01

R

OCR

20K

Ω

C

FB

VN10

R

S

1W

Ω,

DO MUR120

Q

O

Q

O

D

O

R

S

1W

Ω,

V5 (Pin 27)

R

FBA

1K

Ω

1K

A GND (Pin 28)

C

0.1uF

C

HBR

0.1uF

MUR120

FBA

Ω

*R

FBB

1.07K

S

R

SN

16Ω, 1W

Ω

C

S

0.1uF

*R

13.3K

C

HBR

33uF

C

SN

220pF

FBC

VPP

+

C

Ω

+

C

BAUX

47uF

C

O

0.22uF

+

S

330uF

C

S

330uF

VNN

R

Z

20

Ω,

C

Z

0.22uF

2W

R

4Ω or 8

L

Ω

D

MUR120

B

VN10

R

250

B

C

B

0.1uF

+

L

O

10uH

Ω

*R

FBC

13.3K

Ω

6 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

External Components Description

Components Description R

Inverting input resistance to provide AC gain in conjunction with RF. This input is

I

biased at the BIASCAP voltage (approximately 2.5VDC).

RF Feedback resistor to set AC gain in conjunction with RI. Please refer to the Amplifier

Gain paragraph, in the Application Information section.

CI AC input coupling capacitor which, in conjunction with RI, forms a highpass filter at

.

)CR2(1f

π=

IIC

R

FBA

R

Feedback divider resistor connected to AGND. This value of this resistor depends

FBB

Feedback divider resistor connected to V5. This resistor is normally set at 1kΩ.

on the supply voltage setting and helps set the TA3020 gain in conjunction with R R

F, RFBA,

and R

. Please see the Modulator Feedback Design paragraphs in the

FBC

Application Information Section.

R

Feedback resistor connected from either the OUT1(OUT2) to FBKOUT1(FBKOUT2)

FBC

or speaker ground to FBKGND1(FBKGND2). The value of this resistor depends on the supply voltage setting and helps set the TA3020 gain in conjunction with R R

FBA,

, and R

. It should be noted that the resistor from OUT1(OUT2) to

FBB

FBKOUT1(FBKOUT2) must have a power rating of greater than

Please see the Modulator Feedback Design paragraphs in the Application Information Section.

CFB Feedback delay capacitor that both lowers the idle switching frequency and filters

very high frequency noise from the feedback signal, which improves amplifier performance. The value of C so that the idle switching difference is greater than 40kHz. Please refer to the Application / Test Circuit.

R

Potentiometer used to manually trim the DC offset on the output of the TA3020.

OFA

R

Resistor that limits the manual DC offset trim range and allows for more precise

OFB

adjustment.

R

Bias resistor. Locate close to pin 32 and ground at pin 28.

REF

CA BIASCAP decoupling capacitor. Should be located close to pin 19 and grounded at

pin 28.

DB Bootstrap diode. This diode charges up the bootstrap capacitors when the output is

low (at VNN) to drive the high side gate circuitry. A fast or ultra fast recovery diode is recommended for the bootstrap circuitry. In addition, the bootstrap diode must be able to sustain the entire VPP-VNN voltage. Thus, for most applications, a 150V (or greater) diode should be used.

CB High frequency bootstrap capacitor, which filters the high side gate drive supply.

This capacitor must be located as close to pin 40 (VBOOT1) or pin10 (VBOOT2) for reliable operation. The “negative” side of C HO1COM (pin 46) or HO2COM (pin 4). Please refer to the Application / Test Circuit.

C

Bulk bootstrap capacitor that supplements CB during “clipping” events, which result

BAUX

in a reduction in the average switching frequency.

RB Bootstrap resistor that limits C

(bootstrap supply charging).

CSW VN10 generator filter capacitors. The high frequency capacitor (0.1uF) must be

located close to pin 1 (VN10) to maximize device performance.

CS Supply decoupling for the power supply pins. For optimum performance, these

components should be located close to the TA3020 and returned to their respective ground as shown in the Application/Test Circuit.

R

Main overvoltage and undervoltage sense resistor for the negative supply (VNN).

VNN1

Please refer to the Electrical Characteristics Section for the trip points as well as the hysteresis band. Also, please refer to the Over / Under-voltage Protection section in the Application Information for a detailed discussion of the internal circuit operation and external component selection.

R

Secondary overvoltage and undervoltage sense resistor for the negative supply

VNN2

(VNN). This resistor accounts for the internal V resistor value should be three times that of R

(Refer to the Application/Test Circuit)

2

=

DISS

should be offset between channel 1 and channel 2

FB

should be connected directly to the

B

charging current during TA3020 power up

BAUX

NNSENSE

VNN1

bias of 1.25V. Nominal

. Please refer to the Over / Under-

I, RF,

FBC

I,

)(2RVPPP

.

7 TA3020 – KL Rev. 3.0/09.03

y

Tripath Technology, Inc. - Technical Information

voltage Protection section in the Application Information for a detailed discussion of the internal circuit operation and external component selection.

R

Main overvoltage and undervoltage sense resistor for the positive supply (VPP).

VPP1

Please refer to the Electrical Characteristics Section for the trip points as well as the hysteresis band. Also, please refer to the Over / Under-voltage Protection section in the Application Information for a detailed discussion of the internal circuit operation and external component selection.

R

Secondary overvoltage and undervoltage sense resistor for the positive supply

VPP2

(VPP). This resistor accounts for the internal V resistor value should be equal to that of R

VPP1

PPSENSE

. Please refer to the Over / Under-

bias of 2.5V. Nominal

voltage Protection section in the Application Information for a detailed discussion of the internal circuit operation and external component selection.

RS Over-current sense resistor. Please refer to the section, Setting the Over-current

Threshold, in the Application Information for a discussion of how to choose the value of R

to obtain a specific current limit trip point.

S

R

Over-current “trim” resistor, which, in conjunction with RS, sets the current trip point.

OCR

Please refer to the section, Setting the Over-current Threshold, in the Application Information for a discussion of how to calculate the value of R

C

Over-current filter capacitor, which filters the overcurrent signal at the OCR pins to

OCR

.

account for the half-wave rectified current sense circuit internal to the TA3020. A typical value for this component is 220pF. In addition, this component should be located near pin 31 or pin 33 as possible.

C

Supply decoupling for the high current Half-bridge supply pins. These components

HBR

must be located as close to the output MOSFETs as possible to minimize output ringing which causes power supply overshoot. By reducing overshoot, these capacitors maximize both the TA3020 and output MOSFET reliability. These capacitors should have good high frequency performance including low ESR and low ESL. In addition, the capacitor rating must be twice the maximum VPP voltage. Panasonic EB capacitors are ideal for the bulk storage (nominally 33uF) due to their high ripple current and high frequency design.

RG Gate resistor, which is used to control the MOSFET rise/ fall times. This resistor

serves to dampen the parasitics at the MOSFET gates, which, in turn, minimizes ringing and output overshoots. The typical power rating is 1 watt.

CZ Zobel capacitor, which in conjunction with RZ, terminates the output filter at high

frequencies. Use a high quality film capacitor capable of sustaining the ripple current caused by the switching outputs.

RZ Zobel resistor, which in conjunction with CZ, terminates the output filter at high

frequencies. The combination of R

and CZ minimizes peaking of the output filter

Z

under both no load conditions or with real world loads, including loudspeakers which usually exhibit a rising impedance with increasing frequency. Depending on the program material, the power rating of R

may need to be adjusted. The typical

Z

power rating is 2 watts.

LO Output inductor, which in conjunction with CO, demodulates (filters) the switching

waveform into an audio signal. Forms a second order filter with a cutoff frequency of

C

O

Output capacitor, which, in conjunction with L waveform into an audio signal. Forms a second order low-pass filter with a cutoff

π=

frequency of

and a quality factor of

)CL2(1f

OOC

and a quality factor of

π=

)CL2(1f

OOC

, demodulates (filters) the switching

O

.

CLCRQ =

OOOL

.

Use

CLCRQ =

OOOL

a high quality film capacitor capable of sustaining the ripple current caused by the switching outputs.

DS Source to drain diodes. For these diodes to be effective they must be placed close

to the TA3020. These diodes absorb any high frequency over/ under shoots caused by the output inductor L

during high output current conditions. An ultra fast

O

recovery diode that can sustain the entire VPP-VNN voltage should be used. In most applications a 150V or greater diode must be used.

DO Source to source and drain to drain diodes. A diode must be connected from the

source of the high side MOSFET to the source of the low side MOSFET. Also, a diode must be connected from the drain of the high side MOSFET to the drain of the low side MOSFET. These diodes absorb an

high frequency over/ under shoots

8 TA3020 – KL Rev. 3.0/09.03

Tripath Technology, Inc. - Technical Information

caused by the output inductor LO during high output current conditions. An ultra fast recovery diode that can sustain the entire VPP-VNN voltage should be used. In most applications a 150V or greater diode must be used.

RSN Output snubber resistor. This resistor forms a low pass filter with CSN with a

frequency of f

= 1/(2πRSNCSN). This RC filter removes any high frequency

C

overshoots that can be present on the switching output waveform. This RC filter must be connected directly across the drain and source of the low side output MOSFET.

CSN Output snubber capacitor. This capacitor forms a low pass filter with RSN with a

frequency of f

= 1/(2πRSNCSN). This RC filter removes any high frequency

C

overshoots that can be present on the switching output waveform. This RC filter must be connected directly across the drain and source of the low side output MOSFET.

DG Gate diode, placed in parallel to the gate resistor. This diode will help discharge the

parasitic capacitance at the MOSFET gates, thus decreasing the MOSFET fall time. This helps reduce shoot through current between the top side and bottom side output MOSFETs.

9 TA3020 – KL Rev. 3.0/09.03