NJU8752/52B
NJU3555
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.
PACKAGE OUTLINE
NJU8752V / 52BV
NJU8752BKM1
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 (NJU8752B)
PIN CONFIGURATION
V
DD
IN
TEST 1
MUTEB
V
SS
OUT
P
V
DDO
1
2
3
4
5
6
7
14
13
12
11
10
9
8
V
SS
COM
TEST 2
STBYB
V
SS
OUT
N
V
DDO
SSOP14 (NJU8752V / 52BV)
20
1
NC
V
DD
NC
V
SS
NC
IN
TEST 1
MUTEB
V
SS
OUT
P
V
DDO
V
DDO
NC
V
DDO
V
DDO
COM
TEST 2
STBYB
V
SS
OUT
N
QFN20 (NJU8752BKM1)
Ver.2011-01-06
-1-
NJU8752/52B
BLOCK DIAGRAM
V
DD
V
SS
V
DDO
IN
-
+
-
COM
+
Pulse
Width
Modulator
OUT
P
V
SS
V
DDO
OUT
N
V
SS
Short
Protector
Soft Start
Control Logic
Low Voltage
Detector
MUTEB
TEST 1
STBYB
TEST 2
PIN DESCRIPTION
No.
SSOP14
1
2
QFN20
19
1
SYMBOL
V
DD
IN
I/O
−
I
Function
Power Supply: V
DD
=3.3V
Signal Input
Maker test 1
3
2
TEST 1
I
This pin must be connected to GND.
Mute Control
4
3
MUTEB
I
Low : Mute ON
High : Mute OFF
5,10,14
4,12,17
V
SS
−
Power GND: V
SS
=0V
6
5
OUT
P
O
Positive Output
7,8
6,7,9,10
V
DDO
−
Output Power Supply : V
DDO
=16.0V max.
9
11
OUT
N
O
Negative Output
Standby Control
11
13
STBYB
I
Low : Standby ON High : Standby OFF
Maker test 2
12
14
TEST 2
I
This pin must be connected to GND.
13
15
COM
−
Analog common
Non connection
−
8,16,18,20
NC
−
*V
SS
(SSOP14:Pin No.5,10,14, QFN20:Pin No.4,12,17) should be connected
at a nearest point to the IC.
*V
DDO
(SSOP14:Pin No.7,8, QFN20:Pin No.6,7,9,10) should be connected
at a nearest point to the IC.
*MUTEB(SSOP14: Pin No.4, QFN20) and STBYB(SSOP14:Pin No.11, QFN20:Pin No.13,
must be connected to V
DD
, when these pins are not used.
-2-
Ver.2011-01-06
NJU8752/52B
NJU3555
FUNCTIONAL DESCRIPTION
(1) Signal Output
The OUT
P
and OUT
N
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 V
DDO
, 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 (OUT
P
and OUT
N
) are high impedance.
(3) Mute
By setting the MUTEB pin to “L”, the Mute function is enabled. In the Mute mode, the output pins (OUT
P
and
OUT
N
) output square wave (Duty: 50%).
(4) Low Voltage Detector
When the power supply voltage drops down to below V
DD
(MIN), the internal oscillation is halted for prevention
to generate unwanted frequency, and the output pins (OUT
P
and OUT
N
) 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
•
Short
•
Short
between OUT
P
and OUT
N
between OUT
P
and V
SS
between OUT
N
and V
SS
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.
Ver.2011-01-06
-3-
NJU8752/52B
ABSOLUTE MAXIMUM RATINGS
(Ta=25°C)
PARAMETER
Supply Voltage
Input Voltage
Operating Temperature
Storage Temperature
SSOP14
Power Dissipation
QFN20
SYMBOL
V
DD
V
DDO
Vin
Topr
Tstg
P
D
RATING
-0.3 ~ +4.0
-0.3 ~ +18.0
-0.3 ~ V
DD
+0.3
-40 ~ +85
-40 ~ +125
450
620
UNIT
V
V
V
°C
°C
mW
* : Mounted on two-layer board of based on the JEDEC.
Note 1) All voltage are relative to “V
SS
=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 V
DD
-V
SS
and V
DDO
-V
SS
should be connected for stable operation.
ELECTRICAL CHARACTERISTICS
-NJU8752-
(Ta=25°C, V
DD
=3.3V, V
DDO
=12.0V, V
SS
=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
V
DD
Supply Voltage
V
DDO
Supply Voltage
Input Impedance
Voltage Gain
Output THD
Maximum Output
S/N
Dynamic Range
Maximum Mute Attenuation
Operating Current(Stanby)
Operating Current
(No signal input)
Input Voltage
Input Leakage Current
SYMBOL
V
DD
V
DDO
Z
IN
A
V
THD
Vo
SN
Drange
MAT
I
ST
I
DD
V
IH
V
IL
I
LK
CONDITIONS
MIN
2.7
6.0
-
-
-
7
-
-
90
-
-
0.7V
DD
0
-
TYP
3.3
12.0
20
31
0.05
10
80
83
-
-
3.5
-
-
-
MAX
3.6
16.0
-
-
0.08
-
-
-
-
1
10
V
DD
0.3V
DD
±1.0
UNIT
V
V
kΩ
dB
%
Vrms
dB
dB
dB
µA
mA
V
V
µA
Note
IN pin
Input Signal Level
=200mVrms
Output THD=10%
A weight
A weight
4
4
4
No-load operating
No Signal Input
MUTEB, STBYB pins
MUTEB, STBYB pins
MUTEB, STBYB pins
-4-
Ver.2011-01-06
NJU8752/52B
NJU3555
-NJU8752B-
(Ta=25°C, V
DD
=3.3V, V
DDO
=12.0V, V
SS
=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
V
DD
Supply Voltage
V
DDO
Supply Voltage
Input Impedance
Voltage Gain
Output THD
Maximum Output
S/N
Dynamic Range
Maximum Mute Attenuation
Operating Current(Stanby)
Operating Current
(No signal input)
Input Voltage
Input Leakage Current
SYMBOL
V
DD
V
DDO
Z
IN
A
V
THD
Vo
SN
Drange
MAT
I
ST
I
DD
V
IH
V
IL
I
LK
CONDITIONS
MIN
3.1
6.0
-
-
-
7
-
-
-
-
-
0.7V
DD
0
-
TYP
3.3
12.0
20
20
0.05
10
80
83
90
-
3.5
-
-
-
MAX
3.6
16.0
-
-
0.08
-
-
-
-
1
10
V
DD
0.3V
DD
±1.0
UNIT
V
V
kΩ
dB
%
Vrms
dB
dB
dB
µA
mA
V
V
µA
Note
IN pin
Input Signal Level
=700mVrms
Output THD=10%
A weight
A weight
4
4
4
No-load operating
No Signal Input
MUTEB, STBYB pins
MUTEB, STBYB pins
MUTEB, STBYB pins
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.
Input Signal
NJU8752/52B
2nd-order
LC LPF
Filter
20kHz
(AES17)
THD
Measuring
Apparatus
NJU8752/52B
Test Board
Audio Analyzer
Figure 1. Output THD, S/N and Dynamic Range Test System
2nd-order LPF
Filters
: Refer to “Typical Application Circuit”.
: 22Hz HPF + 20kHz LPF(AES17)
(with the A-Weight filter for S/N and Dynamic-range tests)
Ver.2011-01-06
-5-
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