NSC LM4652TF, LM4651N, LM4652TA Datasheet

August 2000

LM4651 & LM4652 Overture

LM4651 & LM4652

Overture

™

Audio Power Amplifier

170W Class D Audio Power Amplifier Solution

General Description

The IC combination of the LM4651 driver and the LM4652 power MOSFET provides a high efficiency, Class D subwoofer amplifier solution.

The LM4651 is a fully integrated conventional pulse width modulator driver IC. The IC contains short circuit, under voltage, over modulation, and thermal shut down protection circuitry. It contains a standby function, which shuts down the pulse width modulation and minimizes supply current. The LM4652 is a fully integrated H-bridge power MOSFET IC in a TO-220 power package. Together, these two IC’s form a simple, compact high power audio amplifier solution complete with protection normally seen only in Class AB amplifiers. Few external components and minimal traces between the IC’s keep the PCB area small and aids in EMI control.

The near rail-to-rail switching amplifier substantially increases the efficiencycompared to Class AB amplifiers. This high efficiency solution significantly reduces the heat sink size compared to a Class AB IC of the same power level. This two-chip solution is optimum for powered subwoofers and self powered speakers.

Key Specifications

n Output power into 4Ω with<10% THD. 170W (Typ) n THD at 10W, 4Ω, 10 − 500Hz. n Maximum efficiency at 125W 85% (Typ) n Standby attenuation.

Features

n Conventional pulse width modulation. n Externally controllable switching frequency. n 50kHZ to 200kHz switching frequency range. n Integrated error amp and feedback amp. n Turn−on soft start and under voltage lockout. n Over modulation protection (soft clipping). n Short circuit current limiting and thermal shutdown

protection.

n 15 Lead TO−220 isolated package. n Self checking protection diagnostic.

Applications

n Powered subwoofers for home theater and PC’s n Car booster amplifier n Self-powered speakers

0.3% THD (Typ)

100dB (Min)

™

170W Class D Audio Power Amplifier Solution

Connection Diagrams

LM4651 Plastic Package

Top View

Order Number LM4651N

See NS Package Number N28B

DS101277-72

LM4652 Plastic Package (Note 8)

DS101277-73

Isolated TO-220 Package

Order Number LM4652TF

See NS Package Number TF15B

Non-Isolated TO-220 Package

Order Number LM4652TA

See NS Package Number TA15A

Overture®is a registered trademark of National Semiconductor Corporation.

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

Supply Voltage Output Current (LM4652) 10A

LM4651 & LM4652

Power Dissipation (LM4651) (Note 3) 1.5W Power Dissipation (LM4652) (Note 3) 32W

22V

Operating Ratings (Notes 1, 2)

Temperature Range −40˚C ≤ T Supply Voltage |V

Thermal Resistance LM4651 N Package

θJA 52˚C/W θJC 22˚C/W

|+|V−| 22V to 44V

ESD Susceptibility (LM4651) (Note 4) 2000V

LM4652 (pins 2,6,10,11) 500V

ESD Susceptibility (LM4651) (Note 5) 200V

LM4652 (pins 2,6,10,11) 100V

LM4652 TF, TO−220 Package

θJA 43˚C/W θJC 2.0˚C/W

Junction Temperature (Note 6) 150˚C Soldering Information

N, TA and TF Package (10 seconds) 260˚C

Storage Temperature −40˚C to + 150˚C

LM4652 T, TO−220 Package

θJA 37˚C/W θJC 1.0˚C/W

System Electrical Characteristics for LM4651 and LM4652 (Notes 1, 2)

The following specifications apply for +VCC= +20V, −VEE= −20V, fSW= 125kHz, fIN= 100Hz, RL=4Ω, unless otherwise specified. Typicals apply for T

Symbol Parameter Conditions

STBY

Total Quiescent Power Supply Current

Standby Current V Standby Attenuation V

Output Power (Continuous Average)

η Efficiency at P η

Efficiency (LM4651 & LM4652)

Power Dissipation (LM4651 + LM4652)

THD+N Total Harmonic Distortion Plus Noise

OUT

Output Noise A Weighted, no signal, RL=4Ω 550 µV SNR Signal-to-Noise Ratio V

Output Offset Voltage VIN= 0V, IO= 0mA, R PSRR Power Supply Rejection Ratio

= 25˚C. For specific circuit values, refer to Figure 1 (Typical Audio Application Circuit).

Typical Units

= 0V, LO= 0mA, |I

CIN

DLY

13 = 5V, Stby: On 17 mA

13 = 5V, Stby: On

=4Ω, 1% THD 125 W

=4Ω, 10% THD 155 W

=8Ω, 1% THD 75 W

=8Ω, 10% THD 90 W

= 75kHz, RL=4Ω, 1% THD 135 W

= 75kHz, RL=4Ω, 10% THD 170 W

=5W PO= 5W, R

= 125W, THD = 1% 85 %

= 125W, THD = 1% (max) 22 W

= 75kHz, PO= 135W,

=0Ω = 10kΩ

=5kΩ 55 %

DLY

VCC+

|+|I

VEE−

THD = 1% (max) 10W, 10Hz ≤ f

≤ 500Hz, AV=18dB

10Hz ≤ BW ≤ 80kHz

A-Wtg, P 22kHz BW, P

=4Ω, 10Hz ≤ BW ≤ 30kHz

= 125W, RL4Ω 92 dB

out

= 125W, RL4Ω 89 dB

out

=0Ω 0.7 V

OFFSET

=−V

=1V

RMS,fAC

= 120Hz

LM4651 & LM4652

237 124

115 dB

22 W

0.3 %

37 dB

≤ +85˚C

mA mA

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Electrical Characteristics for LM4651 (Notes 1, 2, 7)

The following specifications apply for +VCC= +20V, −VEE= −20V, fSW= 125kHz, unless otherwise specified. Limits apply for T

= 25˚C. For specific circuit values, refer to Figure 1 (Typical Audio Application Circuit).

Symbol Parameter Conditions

Standby V

SWerror

dead

OverMod

Total Quiescent Current

Standby Low Input Voltage Not in Standby Mode 0.8 V Standby High Input Voltage In Standby Mode 2.5 2.0 V

Switching Frequency Range 50% Duty Cycle Error R

Dead Time R Over Modulation Protection Time Pulse Width Measured at 50% 310 ns

LM4652 not connected, I

|+|I

VCC+

= 15kΩ 65 kHz

OSC

=0Ω 200 kHz

OSC

=4kΩ,fSW= 125kHz 1 3 %

OSC

=0Ω 27 ns

DLY

VEE−

|, R

DLY

=0Ω

= 0mA,

Min Typical Max Units

15 36 45 mA

LM4651

Electrical Characteristics for LM4652 (Notes 1, 2, 7)

The following specifications apply for +VCC= +20V, −VEE= −20V, unless otherwise specified. Limits apply for TA= 25˚C. For specific circuit values, refer to Figure 1 (Typical Audio Application Circuit).

Symbol Parameter Conditions

DSS

(BR)

DSS

VGS

DS(ON)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance.

Note 2: All voltages are measured with respect to the GND pin unless otherwise specified. Note 3: For operating at case temperatures above 25˚C, the LM4651 must be de−rated based on a 150˚C maximum junction temperature and a thermal resistance

of θ

2.0 ˚C/W (junction to case) for the isolated package (TF) or a thermal resistance of θ

Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Note 5: Machine Model, 220pF-240pF discharge through all pins. Note 6: The operating junction temperature maximum, T Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Note 8: The LM4652TA package TA15A is a non-isolated package, setting the tab of the device and the heat sink at −V potential when the LM4652 is directly

mounted to the heat sink using only thermal compound. If a mica washer is used in addition to thermal compound, θ will be isolated from −V.

Drain−to−Source Breakdown Voltage

VGS = 0 55 V

Drain−to−Source Leakage Current VDS = 44VDC, VGS = 0V 1.0 mA Gate Threshold Voltage VDS = VGS, ID = 1mA Static Drain−to−Source On

Resistance Rise Time

Fall Time Maximum Saturation Drain

Current

= 62 ˚C/W (junction to ambient), while the LM4652 must be de−rated based on a 150˚C maximum junction temperature and a thermal resistance of θJC=

VGS=6V VGD=6V

=0Ω VGD=6V

=0Ω VGS=6V

is 150˚C.

jmax

,ID=6A

, VDS = 40VDC,R

, VDS = 10V

GATE

= 1.0˚C/W (junction to case) for the non-isolated package (T).

Min Typical Max Units

810 A

(case to sink) is increased, but the heat sink

LM4652

0.85 V 200 300 mΩ

25 ns

26 ns

LM4651 & LM4652

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Electrical Characteristics for LM4652 (Notes 1, 2, 7) (Continued)

LM4651 & LM4652

FIGURE 1. Typical Application Circuit and Test Circuit

DS101277-68

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LM4651 Pin Descriptions

Pin No. Symbol Description

1 OUT

2,27 BS

3HG 4HG

,BS

2 1 2

5,15 GND The ground pin for all analog circuitry.

6 +6V 7+V 8 −6V

9F 10 E 11 E

BYP

BKVO

RRIN

RRVO

12 TSD The thermal shut down input pin for the thermal shut down output of the LM4652. 13 STBY Standby function input pin. This pin is CMOS compatible.

14 FBK

16 OSC 17 Delay The dead time setting pin.

18 SCKT Short circuit setting pin. Minimum setting is 10A. 19 FBK

20,21 −V 22,23 −V

DDBYP

24 START

25 LG 26 LG 28 OUT

1 2

The reference pin of the power MOSFET output to the gate drive circuitry. The bootstrap pin provides extra bias to drive the upper gates, HG1,HG2. High−Gate#1 is the gate drive to a top side MOSFET in the H-Bridge. High−Gate#2 is the gate drive to a top side MOSFET in the H-Bridge.

The internally regulated positive voltage output for analog circuitry. This pin is available for internal regulator bypassing only.

The positive supply input for the IC. The internally regulated negative voltage output for analog circuitry. This pin is available

for internal regulator bypassing only. The feedback instrumentation amplifier output pin. The error amplifier inverting input pin. The input audio signal and the feedback signal are

summed at this input pin. The error amplifier output pin.

The feedback instrumentation amplifier pin. This must be connected to the feedback filter from V

(pin 15 on the LM4652 ).

The switching frequency oscillation pin. Adjusting the resistor from 15.5kΩ to 0Ω changes the switching frequency from 75kHz to 225kHz.

The feedback instrumentation amplifier pin. This must be connected to the feedback filter from V

(pin 7 on the LM4652 ).

The regulator output for digital blocks. This pin is for bypassing only. The negative voltage supply pin for the IC. The start up capacitor input pin. This capacitor adjusts the start up time of the diagnostic

sequence for the modulator. Refer to Start up Sequence and Timing in the Application Information section.

Low−Gate#1 is the gate drive to a bottom side MOSFET in the H-Bridge. Low−Gate#2 is the gate drive to a bottom side MOSFET in the H-Bridge. The reference pin of the power MOSFET output to the gate drive circuitry.

LM4651 & LM4652

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LM4652 Pin Descriptions

Pin No. Symbol Description

1 GND A ground reference for the thermal shut down circuitry.

LM4651 & LM4652

2LG 3−V

4 TSD

Low−Gate#1 is the gate input to a bottom side MOSFET in the H-Bridge. The negative voltage supply input for the power MOSFET H-Bridge. The thermal shut down flag pin. This pin transitions to 6V when the die temperature

exceeds 150˚C. 5 NC No connection 6LG 7VO

2 2

Low−Gate#2 is the gate input to a bottom side MOSFET in the H-Bridge.

The switching output pin for one side of the H-Bridge. 8 NC No connection. 9 NC No connection.

10 HG

High−Gate#2 is the gate input to a top side MOSFET in the H-Bridge.

11 NC No connection. 12 NC No connection. 13 +V 14 HG 15 VO

The positive voltage supply input for the power MOSFET H-Bridge.

High−Gate#1 is the gate input to a top side MOSFET in the H-Bridge.

The switching output pin for one side of the H-Bridge.

Note: NC, no connect pins are floating pins. It is best to connect the pins to GND to minimize any noise from being coupled into the pins.

External Components Description (Refer to Figure 1)

Components Functional Description

1. R

2. R

3. R

4. C

Works with R2,R

)/ R

)−(R2/R1) + .5].

fl2

See description above for R1.

Sets the gain and bandwidth of the system by creating a low pass filter for the Error

Amplifier’s feedback with C

See description above for Rf.

fl1

and R

to set the gain of the system. Gain = [(R2/R1) x ((R

fl2

. 3dB pole is at fC= 1/(2πRfCf) (Hz).

Provides a reduction in the feedback with R

5. R

fI1

reduce effects on the pole created by R

fI2

System Gain.

6. R

7. C

8. R

9. C

10. L

11. C

12. C

byp

and C

fI2

fI1

fI3

fI2

note for R

See description above for R

Establish the second pole for the low pass filter in the feedback path at fC=

1/(2πR

See description above for R

Combined with C

= 1/[2π(L12C

Filters high frequency noise from the amplifier’s output to ground. Recommended value

is 0.1µF to 1µF.

See description for L1.

creates a low pass filter with a pole at fC= 1/(2πR

fI1

for effect on System Gain.

1,R2

fI2

) (Hz).

fI3CfI2

fI3

creates a 2−pole, low pass output filter that has a −3dB pole at f

BYP

)

⁄

] (Hz).

BYP

Bypass capacitors for VCC,VEE, analog and digital voltages (VDD, +6V, −6V). See

13. C

B1−CB4

Supply Bypassing and High Frequency PCB Design in the Application Information

section for more information.

14. B

15. R

16. C

START

17. R

18. R

19. D

DLY

SCKT

OSC

Provides the bootstrap capacitance for the boot strap pin.

Sets the dead time or break before make to T

Controls the startup time with T

Sets the output short circuit current with I

START

= (8.5x104)C

SCKT

Controls the switching frequency with fSW=1X109/ (4000 + R

Schottky diode to protect the output MOSFETs from fly back voltages.

should be 10 X R

fI2.RfI1

and C

. See also note for R1,R2for effect on

fI1

= (1.7x10

DLY

START

= (1x105)/ (10kΩ\ R

fI2CfI1

−12

)(500+R

(seconds).

OSC

minimum to

fI2

) (Hz). See also

) (seconds).

DLY

) (A).

SCKT

) (Hz).

fl1

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