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Preliminary
NJU8758
Analog Signal Input Monaural 1.5W Filterless Class D Power Amplifier
GENERAL DESCRIPTION
The NJU8758 is an analog signal input monaural 1.5W filterless class D power amplifier. The NJU8758 is capable of driving 0.6W at 3.3V or 1.5W at 5.0V into 8ohms without external LC low-pass filters. It includes an output-short protector. The NJU8758 incorporates BTL amplifier, which eliminate AC coupling capacitors. The NJU8758 features high power-efficiency by class-D operation, and is suited for security equipment, portable set with speaker, PC, etc.
PACKAGE OUTLINE
NJU8758V
FEATURES
Operating Voltage: 1.8 to 5.5V 1.5 W at 5V into 8ohms No output filters Standby(Hi-Z), Mute Control Built-in Pop noise reduction EQ for Active filter Built-in Low Voltage Detector Built-in Short Protector for each channel CMOS Technology Package Outline: SSOP14
PIN CONFIGURATION
VDD IN EQ1 EQ2 COM MUTEb STBYb
1 2 3 4 5 6 7
14 13 12 11 10 9 8
OUTTEST VSS OUTP VDDO OUTN VSS TEST
Ver.2009-11-10
-1-
NJU8758
BLOCK DIAGRAM
EQ1 EQ2 VDD VDDO
OSCILLATOR
IN
LEVEL SHIFTER PULSE WIDTH MODULATOR LEVEL SHIFTER SHORT PROTECTION
OUTP
COM
BIAS
OUTN
TEST
SOFT START
CONTROL LOGIC
VDD LOW BAT. PROTECTION
VDDO LOW BAT. PROTECTION
VSS
STBYb
MUTEb
VSS
PIN DESCRIPTION
No 1 2 3 4 5 SYMBOL VDD IN EQ1 EQ2 COM I/O I I/O I/O FUNCTION Power supply : VDD=3.3V (*1) Signal input for Active filter for Active filter
Analog common Mute control (*3) 6 MUTEb I MUTEb=Low: MUTE Mode Standby control (*3) 7 STBYb I STBYb=MUTEb=Low: Standby Mode 8 TEST I TEST terminal for maker (*4) 9 VSS Power GND : VSS=0V (*1)(*2) 10 OUTN O Negative output 11 VDDO Output power supply : VDDO =3.3V (*1) 12 OUTP O Positive output 13 VSS Power GND : VSS=0V (*1)(*2) 14 OUTTEST O Short Detect output *1) The relations of "VSS= 0V" and "VDD= VDDO" must be maintained. *2) The VSS should be connected at a nearest point to the IC. *3) The MUTEb and the STBYb must be connected to VDD, when these terminals are not used. *4) The Test terminal must be connected to VSS.
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Ver.2009-11-10
NJU8758 NJU3555
FUNCTIONAL DESCRIPTION
(1) Signal Output (OUTP, OUTN) The OUTP and OUTN generate PMW output signal. (2) Standby (STBYb) By setting the STBYb and MUTEb terminal to "L", the standby mode is enabled. In the standby mode, the entire functions of the NJU8758 enter a low-power state, and the output terminals(OUTP and OUTN) are in high impedance. (3) Mute (MUTEb) By setting the MUTEb terminal to "L", the Mute function is enabled, and the output terminals(OUTP and OUTN) output square wave(Duty: 50%). The NJU8758 has a built-in circuit for the pop-noise reduction at power-on. However the control with the sequence can realize more effective the pop-noise reduction.
VDD,VDDO
STBYb
MUTEb
over 100 ms
Timing for pop-noise reduction
Ver.2009-11-10
-3-
NJU8758
(4) EQ for Active filter (IN, EQ1, EQ2) The NJU8758 has EQ1 and EQ2, which is for active filter. The band-pass filter is calculated as shown below.
RS1 CS1 CF1 RF1
CF2
EQ1 NJU8758 RF
EQ2
RS=27 k RF=32 k
CC
+
RS IN
VIN
Example: The band-pass filter
1 1 1 + sC F2 + RF 1 + R F1 sC F1 H(s ) = - 1 1 + 1 1 sC C + 1 RS + R S1 sC S1
CF1>100 pF (5) Low Voltage Detector When the power supply voltage drops down to below VDD(MIN), the internal circuit is halted, and the output terminals(OUTP and OUTN) become in high impedance. (6) Short Protection Circuit The short protector is enabled in response to following accidents. Short between OUTP and OUTN Short between OUTP and VSS Short between OUTN and VSS When the Short Protector enable, the output terminals (OUTP and OUTN) become in high impedance, and OUTTEST enable" H"(H=VDD). By setting the STBYb terminal to "L", the NJU8758 returns to normal operation. 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 NJU8758.
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Ver.2009-11-10
NJU8758 NJU3555
ABSOLUTE MAXIMUM RATINGS
PARAMETER Supply Voltage Input Voltage Operating Temperature Storage Temperature SYMBOL VDD VDDO Vin Ta Tstg PDMAX2
TERMINAL VDD VDDO IN, STBYb, MUTEb
(Ta=25C) RATING -0.3 to +7.0 -0.3 to +7.0 -0.3 to VDD + 0.3 -40 to +85 -40 to +125
UNIT V V V C C
Mounted on two-layer board of based on the EIAJ, 450 mW Power Tj = 125C Dissipation Mounted on four-layer board of based on the EIAJ, PDMAX4 570 mW Tj = 125C Mounted on two-layer board of based on the EIAJ, ja2 223 C /W Tj = 125C Thermal Resistance Mounted on four -layer board of based on the EIAJ, ja4 176 C /W Tj = 125C Note 3) All voltage are relative to "VSS= 0V" reference. Note 4) Mounted on two-layer/4-layer board of based on the EIA/JEDEC STD Note 5) The IC must be used inside of the "Absolute maximum ratings". Otherwise, a stress may cause permanent damage to the LSI. Note 6) De-coupling capacitors for VDD-VSS and VDDO-VSS should be connected for stable operation. Note 7) The class-D amplifiers are more power efficient, and dissipate power less than general analog-amplifiers. In theory, the NJU8758 actualize quite high output-power such as 1.2W at =5V operation with 8ohms load, it looks as if the NJU8758 exceeds the absolute maximum rating of the power dissipation. However, in practice, the effective output-power of usual music sound is only about 1/10 of its maximum output power, thus it may never exceed the absolute maximum rating. The maximum power dissipation in the system is calculated, as shown below.
PDMAX =
T jMAX [C ] - Ta [C ]
ja [C / W ]
Pdmax: Maximum Power Dissipation, Tjmax: Junction Temperature = 125C Ta: Ambient Temperature, ja: Thermal Resistance of package (SSOP14) = 223C/W Power dissipation of the NJU8758 itself is calculated, as shown below.
PD =
125C - 50C = 336.3mW 223C / W
Ver.2009-11-10
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NJU8758
ELECTRICAL CHARACTERISTICS (7) DC CHARACTERISTICS
(Ta=25C, VDD=VDDO= 3.3V, VSS= 0V, Input Signal=1kHz, Input Signal Level=200mVrms, Load Impedance=8) PARAMETER SYMB OL CONDITIONS
MIN. TYP. MAX.
UNIT
VDD,VDDO Supply Voltage
VDD, VDDO
1.8
3.3
5.5
V
Drain-Source On-state Resistance (High-side) Drain-Source On-state Resistance (Low-side) Input Impedance
RONH
OUTP, OUTN VOUTP,N = VDDO - 0.1 V OUTP, OUTN VOUTP,N = 0.1 V IN VDD, STBYb: "L",
-
0.5
-
RONL
-
0.5
-
RIN
-
27
-
k
IST
Operating Current (Standby)
ISTO
No Load
-
0.1
0.5
A
VDDO, STBYb: "L",
No Load
-
0.1
0.5
A
IDD
-
1.5
-
mA
Operating Current (No signal input)
IDDO
No Load
1.2 mA
VIH
STBYb, MUTEb
1.5
-
VDD
V
Input Voltage
VIL STBYb, MUTEb 0 0.5 V
Input Leakage Current
ILK
STBYb, MUTEb
-
-
1
A
Frequency
fOSC
-
320
-
kHz
Start up Time
TON
MUTEb: "L"
-
205
-
ms
Voltage Gain
AV
No Load
-
22.9
-
dB
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Ver.2009-11-10
NJU8758 NJU3555
(8) AC CHARACTERISTICS (Ta=25C, VDD= VDDL= VDDR=3.3V, Input Signal=1kHz, Input Signal Level=200mVrms, Load Impedan ce=8,) MIN. TYP. MAX. PARAMETER CONDITIONS SYMBOL UNIT
Output Power Efficiency THD+N
EEFF THD+N=10 % 80 %
THD+N
PO=200 mW VDD=VDDO=3.3 V THD+N=10 %
-
0.05
-
%
-
0.66
-
W
Output Power
PO VDD=VDDO=5.0 V THD+N=10 % 1.5 W
S/N
S/N
A-weight VDD=VDDO=5.0 V
-
84
-
dB
Test system of the output THD
NJU8758
AUX-0025
Filters 20kHz(AES17)
THD METER
NJU8758 Evaluation Board
LPF
Audio Analyzer
Output THD Test System
Ver.2009-11-10
-7-
NJU8758
TYPICAL APPLICATION CIRCUIT
Battery
+
+
10 F
1 F
10 F 0.1 F
VDD(1)
VDDO(11) OUTP(12)
1 F
IN(2)
8
EQ1(3)
100 pF
EQ2(4) STBYb(7) MUTEb(6) COM(5)
10 F
+
NJU8758
VSS(9,13)
OUTN(10)
TEST(8)
TYPICAL APPLICATION CIRCUIT
Note 8) De-coupling capacitors must be connected between each power supply terminal and GND (VDD-VSS, VDDO-VSS). Note 9) VSS should be connected at a nearest point to the IC on PCB. Note 10) IN, EQ1 and EQ2 should be not designed near OUTP and OUTN, which emit PWM noise. Note 11) The power supply for VDDO requires fast driving response performance such as a switching regulator for better THD. Note 12) 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. Note 13) The transition time for MUTEB and STBYB signals must be less than 100s. Otherwise, a malfunction may be occurred. Note 14) (1) - (12) indicates terminal 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.
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Ver.2009-11-10

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