NJU8752BKM1 - New Japan Radio Co., Ltd.

NJU3555NJU8752/52B

-1-

Ver.2004-08-05

Analog Signal Input Class D Amplifier for Piezo Speaker

! GENERAL DESCRIPTION

The NJU8752/NJU8752B is an analog signal input

monaural class D amplifier for Piezo speaker. The

NJU8752/52B includes Inversion operational amplifier

input circuit, PWM modulator, an output-short protector

and a low voltage detector. Input part operates on

3.3V(TYP) as power supply and Output part operates

up to 16.0V(MAX). Therefore, it drives Piezo speaker

with louder sound and High efficiency.

The NJU8752/52B incorporates BTL amplifier, which

eliminate AC coupling capacitors, capable of driving

Piezo speaker with simple external LC low-pass filters.

Class D operation achieves lower power operation for

Piezo speaker, thus the NJU8752/52B is suited for

battery powered applications.

! FEATURES

# Piezo Speaker Driving

# 1-channel Analog Signal Input, 1-channel BTL Output

# Standby(Hi-Z), Mute Control

# Voltage Gain 31dB(NJU8752)

20dB(NJU8752B)

# Built-in Low Voltage Detector

# Built-in Short Protector

# Operating Voltage Input: 2.7 ~ 3.6V (NJU8752)

3.1 ~ 3.6V (NJU8752B)

Output: 6.0 ~ 16.0V

# C-MOS Technology

# Package Outline SSOP14 (NJU8752 / 52B)

QFN20 / QFN28 (NJU8752B)

! PIN CONFIGURATION

! PACKAGE OUTLINE

NJU8752V / 52BV

PRELIMINARY

NJU8752BKM1

NJU8752BKP4

VDD

IN

TEST 1

MUTEB

VSS

COM

TEST 2

STBYB

VSS

1

2

3

4

5

14

13

12

11

10

6

7

9

8

OUTP

VDDO

OUTN

VDDO

SSOP14 (NJU8752V / 52BV)

20

1

NC

VSS

VDD

COM

TEST 2

STBYB

VSS

OUT

N

VDDO

NC

OUT

P

VSS

MUTEB

TEST 1

IN

QFN20

(

NJU8752BKM1

)

QFN28 (NJU8752BKP4)

28

1

NC

VSS

VDD

COM

TEST 2

STBYB

OUTN

VDDO

NC

OUTP

VSS

MUTEB

TEST 1

IN

NC

VSS

NC

NJU8752/52B

- 2 - Ver.2004-08-05

! BLOCK DIAGR AM

! PIN DESCRIPTION

No.

SSOP14 QFN20 QFN28 SYMBOL I/O Function

1 19 26 VDD − Power Supply: VDD=3.3V

2 1 1 IN I Signal Input

3 2 2 TEST 1 I

Maker test 1

This pin must be connected to GND.

4 3 3 MUTEB I

Mute Control

Low : Mute ON High : Mute OFF

5,10,14 4,12,17 5,17,24 VSS − Power GND: VSS=0V

6 5 7 OUTP O Positive Output

7,8 6,7,9,10 8,9,13,14 VDDO − Output Power Supply : VDDO=16.0V max.

9 11 15 OUTN O Negative Output

11 13 18 STBYB I

Standby Control

Low : Standby ON High : Standby OFF

12 14 19 TEST 2 I

Maker test 2

This pin must be connected to GND.

13 15 21 COM − Analog common

− 8,16,18,20

4,6,10,11,

12,16,20,22,

23,25,27,28

NC − Non connection

*VSS(SSOP14:Pin No.5,10,14, QFN20:Pin No.4,12,17, QFN28:Pin No.5,17,24) should be connected

at a nearest point to the IC.

*VDDO(SSOP14:Pin No.7,8, QFN20:Pin No.6,7,9,10, QFN28:Pin No.8,9,13,14) should be connected

at a nearest point to the IC.

*MUTEB(SSOP14: Pin No.4, QFN20, QFN28:Pin No.3) and STBYB(SSOP14:Pin No.11, QFN20:Pin No.13,

QFN28:Pin No.18) must be connected to VDD, when these pins are not used.

Pulse

Width

Modulator

Short

Protector

VDD

Control Logic Low Voltage

Detecto

r

Soft Start

VSS

+

-

+

-

IN

COM

MUTEB TEST 1

STBYB TEST 2

VDDO

OUTP

VSS

VDDO

OUTN

VSS

NJU3555NJU8752/52B

-3-

Ver.2004-08-05

! FUNCTIONAL DESCRIPTION

(1) Signal Output

The OUTP and OUTN generate PWM output signals, which will be converted to analog signal via external

2nd-order or higher LC filter. A switching regulator with a high response against a voltage fluctuation is the best

selection for the VDDO, which are the power supply for output drivers. To obtain better THD performance, the

stabilization of the power is required.

(2) Standby

By setting the STBYB pin to “L”, the standby mode is enabled. In the standby mode, the entire functions of the

NJU8752/52B enter a low-power state, and the output pins (OUTP and OUTN) are high impedance.

(3) Mute

By setting the MUTEB pin to “L”, the Mute function is enabled. In the Mute mode, the output pins (OUTP and

OUTN) output square wave (Duty: 50%).

(4) Low Voltage Detector

When the power supply voltage drops down to below VDD (MIN), the internal oscillation is halted for prevention

to generate unwanted frequency, and the output pins (OUTP and OUTN) become in high impedance.

(5) Short Circuit Protection

The short protector, which protects the NJU8752/52B against high short-circuit current, turns off the output

driver. After about 5 seconds from the protection, the NJU8752/52B returns to normal operation. The short

protector functions at the following accidents.

• Short between OUTP and OUTN

• Short between OUTP and VSS

• Short between OUTN and VSS

Note 1) The detectable current and the period for the protection depend on the power supply voltage

and ambient temperature.

Note 2) The short protector is not effective for a long term short-circuit but for an instantaneous accident.

Continuous high-current may cause permanent damage to the NJU8752/52B.

NJU8752/52B

- 4 - Ver.2004-08-05

! ABSOLUTE MAXIMUM R ATINGS

(Ta=25°C)

PARAMETER SYMBOL RATING UNIT

Supply Voltage VDD

VDDO

-0.3 ~ +4.0

-0.3 ~ +18.0

V

Input Voltage Vin -0.3 ~ VDD+0.3 V

Operating Temperature Topr -40 ~ +85 °C

Storage Temperature Tstg -40 ~ +125 °C

SSOP14 450

QFN20 620

Power Dissipation

QFN28

PD

640

mW

* : Mounted on two-layer board of based on the JEDEC.

Note 1) All voltage are relative to “VSS =0V” reference.

Note 2) The LSI must be used inside of the “Absolute maximum ratings”. Otherwise, a stress may cause

permanent damage to the LSI.

Note 3) De-coupling capacitors for VDD-VSS and VDDO-VSS should be connected for stable operation.

! ELECTRICAL C HARACTE RISTICS

-NJU8752-

(Ta=25°C, VDD=3.3V, VDDO=12.0V, VSS=0V,Input Signal=1kHz, Input Signal Level=200mVrms,

Frequency Band=20Hz~20kHz, Load Impedance=0.8µF, 2nd-order 34kHz LC Filter(Q=0.75))

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT Note

VDD Supply Voltage VDD 2.7 3.3 3.6 V

VDDO Supply Voltage VDDO 6.0 12.0 16.0 V

Input Impedance ZIN IN pin - 20 - kΩ

Voltage Gain AV - 31 - dB

Output THD THD Input Signal Level

=200mVrms - 0.05 0.08 % 4

Maximum Output Vo Output THD=10% 7 10 - Vrms

S/N SN A weight - 80 - dB 4

Dynamic Range Drange A weight - 83 - dB 4

Maximum Mute Attenuation MAT 90 - - dB

Operating Current(Stanby) IST - - 1 µA

Operating Current

(No signal input) IDD No-load operating

No Signal Input - 3.5 10 mA

VIH MUTEB, STBYB pins 0.7VDD - VDD V

Input Voltage VIL MUTEB, STBYB pins 0 - 0.3VDD V

Input Leakage Current ILK MUTEB, STBYB pins - - ±1.0 µA

NJU3555NJU8752/52B

-5-

Ver.2004-08-05

-NJU8752B-

(Ta=25°C, VDD=3.3V, VDDO=12.0V, VSS=0V,Input Signal=1kHz, Input Signal Level=700mVrms,

Frequency Band=20Hz~20kHz, Load Impedance=0.8µF, 2nd-order 34kHz LC Filter(Q=0.75))

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT Note

VDD Supply Voltage VDD 3.1 3.3 3.6 V

VDDO Supply Voltage VDDO 6.0 12.0 16.0 V

Input Impedance ZIN IN pin - 20 - kΩ

Voltage Gain AV - 20 - dB

Output THD THD Input Signal Level

=700mVrms - 0.05 0.08 % 4

Maximum Output Vo Output THD=10% 7 10 - Vrms

S/N SN A weight - 80 - dB 4

Dynamic Range Drange A weight - 83 - dB 4

Maximum Mute Attenuation MAT - 90 - dB

Operating Current(Stanby) IST - - 1

µA

Operating Current

(No signal input) IDD No-load operating

No Signal Input - 3.5 10 mA

VIH MUTEB, STBYB pins 0.7VDD - VDD V

Input Voltage VIL MUTEB, STBYB pins 0 - 0.3VDD V

Input Leakage Current ILK MUTEB, STBYB pins - - ±1.0 µA

Note 4) Test system of the output THD, S/N and Dynamic Range

The output THD, S/N and dynamic range are tested in the system shown in Figure 1, where a 2nd-order

LC LPF and another filter incorporated in an audio analyzer are used.

2nd-order LPF : Refer to “Typical Application Circuit”.

Filters : 22Hz HPF + 20kHz LPF(AES17)

(with the A-Weight filter for S/N and Dynamic-range tests)

Input Signal

THD

Measuring

Apparatus

Filte

r

20kHz

(AES17)

2nd-order

LC LPF

NJU8752/52B Test Board Audio Analyzer

Figure 1. Output THD, S/N and Dynamic Range Test System

NJU8752/52B

- 6 - Ver.2004-08-05

! TYPICAL APPLICATION CIRCUIT

Figure 2.1 Application Circuit example (SSOP14)

NJU8752/52B

VDD(1)

VSS(14)

OUTP(6)

OUTN(9)

33~47

µ

H

Piezo Speaker

0.1

µ

F

0.1

µ

F

VDDO

(

7

)

VSS(5)

0.1

µ

F 10µFVDDO

0.1

µ

F

10

µ

F

VDD

IN(2) IN

COM(13)

MUTEB(4)

STBYB

(

11

)

2.2

µ

F

10

µ

F

VDDO

(

8

)

VSS(10)

0.1

µ

F10µFVDDO

TEST1(3)

TEST2

(

12

)

33~47

µ

H

5~10Ω

0.5~2

µ

F

3.3kΩ

0.01

µ

F

•LLB2520 is manufactured by TOKO, INC.

For detail information, please refer its technical papers.

LLB2520

NJU8752/52B

VDD(19)

VSS(17)

OUTP(5)

OUTN(11)

33~47

µ

H

0.1

µ

F

0.1

µ

F

VDDO

(

6,7

)

VSS(4)

0.1

µ

F 10µFVDDO

0.1

µ

F

10

µ

F

VDD

IN(1) IN

COM(15)

MUTEB(3)

STBYB

(

13

)

2.2

µ

F

10

µ

F

VDDO

(

9,10

)

VSS(12)

0.1

µ

F10µFVDDO

TEST1(2)

TEST2

(

14

)

33~47

µ

H

5~10Ω

3.3kΩ

0.01

µ

F

LLB2520

Piezo Speaker

0.5~2

µ

F

Figure 2.2 Application Circuit example (QFN20)

NJU3555NJU8752/52B

-7-

Ver.2004-08-05

Note 5) De-coupling capacitors must be connected between each power supply pin and GND.

The capacity value should be adjusted on the application circuit and the operation temperature. It may

malfunction if capacity value is small.

Note 6) The power supply for VDDO require fast driving response performance such as a switching regulator for

better THD.

THD performance becomes worse by ripple if the capacity of De-coupling capacitors is small.

Note 7) The above circuit shows only application example and does not guarantee the any electrical

characteristics. Therefore, please test the circuit carefully to fit your application.

The cutoff frequency of the LC filter influences the quality of sound.

The Q factor of the LC filter must be less than “1”. Otherwise, the operating current increase when the

frequency of input signal is closed to the cutoff frequency.

Note 8) The transition time for MUTEB and STBYB signals must be less than 100µs. Otherwise, a malfunction

may be occurred.

Note 9) (1)-(26) indicates pin number.

[CAUTION]

The specifications on this databook are only

given for information , without any guarantee

as regards either mistakes or omissions. The

application circuits in this databook are

described only to show representative usages

of the product and not intended for the

guarantee or permission of any right including

the industrial rights.

Piezo Speaker

0.5~2

µ

F

NJU8752/52B

VDD(26)

VSS(24)

OUTP(7)

OUTN(15)

33~47

µ

H

0.1

µ

F

0.1

µ

F

VDDO

(

8,9

)

VSS(5)

0.1

µ

F 10µFVDDO

0.1

µ

F

10

µ

F

VDD

IN(1) IN

COM(21)

MUTEB(3)

STBYB

(

18

)

2.2

µ

F

10

µ

F

VDDO

(

13,14

)

VSS(17)

0.1

µ

F10µFVDDO

TEST1(2)

TEST2

(

19

)

33~47

µ

H

5~10Ω

3.3kΩ

0.01

µ

F

LLB2520

•LLB2520 is manufactured by TOKO, INC.

For detail information, please refer its technical papers.

Figure 2.3 Application Circuit example (QFN28)