ISSI IS31AP4913

IS31AP4913
3D AND BASS ENHANCEMENT STEREO HEADPHONE DRIVER
December 2011
GENERAL DESCRIPTION
FEATURES
The IS31AP4913 is a stereo headphone driver
designed to allow the removal of the output
DC-blocking capacitors for reduced component count
and cost. The IS31AP4913 is ideal for small portable
electronics where size and cost are in concerns.
The IS31AP4913 also features 3D and bass
enhancement which can be externally adjusted by a
simple RC network.
IS31AP4913 is available in QFN-20 (3mm × 3mm)
packages. It operates from 2.7V to 5.5V over the
temperature range of -40°C to +85°C.










No output DC-blocking capacitors
Bass enhancement
3D enhancement
Low output noise (8µV)
High SNR (102dB)
-92dB PSRR
Pulse Count Control serial interface
Thermal protection circuit
Integrated click-and-pop suppression circuitry
QFN-20 (3mm × 3mm) package
APPLICATIONS




Cellular handsets and PDAs
Notebook PC
MP3
Portable gaming
TYPICAL APPLICATION CIRCUIT
6.8pF
RR_F1
20k
20
CR_IN
0.47 F
RR_IN
30k
Audio In
2
CR_B RR_B
22nF 510k
VBattery
4.7 F
12
RR_F3
120k
1
INFR
BASSR
RR_F2
20k
OUTR
VSS
INR
VREF
PGND
VCC
SGND
14
18
13
4.7 F 2.2 F
17
10
0.1 F
IS31AP4913
11
Mode Control
CTRL
3DR
3DL
3
4
R3D
4.7k
C3D
47nF
100k
5
Audio In
CL_IN
0.47 F
RL_IN
30k
CL_B RL_B
22nF 510k
6
CN
INL
BASSL
RL_F1
20k
CP
INFL
7
RL_F3
120k
OUTL
19
16
2.2 F
15
RL_F2
20k
6.8pF
Figure 1
Typical Application Circuit
Note: The SGND and PGND pins of the IS31AP4913 must be routed separately back to the decoupling capacitor in order to provide proper
device operation. If the SGND and PGND pins are connected directly to each other, the part will function without the risk of failure, but the noise
and THD performance do not meet the specifications.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
1
IS31AP4913
PIN CONFIGURATION
Package
Pin Configuration (Top View)
QFN-20
INFR 1
15 OUTL
INR 2
14 OUTR
3DR 3
13 VREF
3DL 4
12 VCC
INL 5
11 CTRL
PIN DESCRIPTION
No.
Pin
Description
1
INFR
Right channel feedback loop in.
2
INR
Right channel audio input.
3
3DR
3D control input.
4
3DL
3D control input.
5
INL
Left channel audio input.
6
BASSL
Left channel bass control out.
7
INFL
Left channel feedback loop in.
8, 9
NC
No connection.
10
SGND
Signal Ground.
11
CTRL
Shutdown and 3D/Bass enable control terminal.
12
VCC
Supply voltage.
13
VREF
Internal produced supply voltage for charge pump and
audio power amplifier.
14
OUTL
Left channel audio output.
15
OUTR
Right channel audio output.
16
CP
Charge pump flying capacitor positive terminal.
17
PGND
Power ground.
18
VSS
Output from charge pump.
19
CN
Charge pump flying capacitor negative terminal.
20
BASSR
Right channel bass control out.
Thermal Pad
Connect to GND.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
2
IS31AP4913
ORDERING INFORMATION
Industrial Range: -40°C to +85°C
Order Part No.
Package
QTY/Reel
IS31AP4913-QFLS2-TR
QFN-20, Lead-free
2500
Copyright © 2011 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances
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Rev.A, 11/17/2011
3
IS31AP4913
ABSOLUTE MAXIMUM RATINGS
Supply voltage, VDD
Voltage at any input pin
Maximum junction temperature, TJMAX
Storage temperature range, TSTG
Operating temperature range, TA
ESD (HBM)
-0.3V ~ +6.0V
-0.3V ~ VDD+0.3V
150°C
-65°C ~ +150°C
−40°C ~ +85°C
3kV
Note:
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and
functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
VCC = 2.7V ~ 5.5V, TA = 25°C, unless otherwise noted. Typical value is TA = 25°C, VCC = 3.6V.
Symbol
Parameter
Condition
VCC
Supply voltage
ICC
Quiescent current
No load
ISD
Shutdown current
VSDB = 0V
Min.
Typ.
2.7
FOSC
Operating frequency
|VOS|
Output offset voltage
VIH
High-level input voltage
VIL
Low-level input voltage
3
V(IN) = 0V
Max.
Unit
5.5
V
5
mA
1
µA
250
kHz
1
mV
1.4
V
0.4
V
Max.
Unit
ELECTRICAL CHARACTERISTICS (Note 1)
TA = 25°C, VCC = 3.6V, unless otherwise noted.
Symbol
PO
THD+N
tWU
Parameter
Condition
Output power
THD+N = 1%，RL = 32Ω，f = 1kHz
Total harmonic
plus noise
Wake-up
shutdown
Min.
distortion
time
VNO
Output voltage noise
SNR
Signal-to-noise ratio
30
mW
0.05
%
39
ms
VP-P = 200mV，RL = 32Ω，f = 217Hz
-92
dB
VP-P = 200mV，RL = 32Ω，f = 1kHz
-90
dB
8
µV
102
dB
PO = 20mW，RL = 32Ω，f = 1kHz
from
PSRR Power supply rejection ratio
Typ.
PO = 30mW，THD+N = 1%
tLO
Mode control low time
1
10
μs
tHI
Mode control high time
1
10
μs
tOFF
CTRL off time for shutdown
200
μs
Note 1: Guaranteed by design.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
4
IS31AP4913
TYPICAL PERFORMANCE CHARACTERISTIC
20
20
10
5
VCC = 3.0V
RL = 32Ω
10
5
2
THD+N(%)
2
THD+N(%)
VCC = 3.6V
RL = 32Ω
1
0.5
f = 10kHz
0.2
1
0.5
f = 10kHz
0.2
0.1
0.1
0.05
0.05
f = 1kHz
f = 1kHz
0.02
0.01
1m
0.02
f = 20Hz
2m
5m
10m
20m
0.01
1m
100m
50m
f = 20Hz
2m
5m
THD+N vs. Output Power
5
Figure 3
VCC = 4.2V
RL = 32Ω
0.5
THD+N(%)
THD+N(%)
2
1
0.5
f = 10kHz
0.2
THD+N vs. Output Power
VCC = 3.0V~4.2V
RL = 32Ω
PO = 20mW
0.2
0.1
0.05
0.1
0.05
f = 1kHz
0.02
0.01
1m
0.02
f = 20Hz
2m
5m
10m
20m
0.01
20
100m
50m
50
100
200
Output Power(W)
Figure 4
500
1k
2k
5k
10k 20k
5k
10k
Frequency(Hz)
THD+N vs. Output Power
Figure 5
20u
THD+N vs. Frequency
+0
VCC = 3.6V, 4.2V
RL = 32Ω
-20
10u
VCC = 3.6V, 4.2V
RL = 32Ω
Input Grounded
-40
7u
PSRR(dB)
Output Voltage(V)
100m
50m
1
20
10
20m
Output Power(W)
Output Power(W)
Figure 2
10m
5u
3u
-60
-80
2u
-100
1u
20
50
100
200
500
1k
2k
5k
10k
20k
-120
20
50
100
Noise
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
500
1k
2k
20k
Frequency(Hz)
Frequency(Hz)
Figure 6
200
Figure 7
PSRR vs. Frequency
5
IS31AP4913
+10
+8
Gain(dB)
+6
+4
+2
0
-2
-4
20
VCC = 3.6V
RL = 32Ω
Bass Enable
50
100
200
500
1k
2k
5k
10k
20k
Frequency(H z)
Figure 8
Gain vs. Frequency (Bass Enable Mode)
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
6
IS31AP4913
APPLICATION INFORMATION
GENERAL DESCRIPTION
GAIN SETTING
The IS31AP4913 is a high quality stereo headphone
driver with 3D and bass enhancement.
The input resistors (RIN) and feedback resistors (RF)
set the gain of the amplifier according to Equation (1).
OPERATING MODE
The operating mode is controlled by Pulse Count
Control (PCC wire) serial interface. The interface
records rising edges of the CTRL pin and decodes
them into 4 operating mode (Figure 9).
If the CTRL pin is pulled to high, receiving one rising
edge, the IC starts up and operates in Mode 1. If the
CTRL pin receives two rising edges, the IC operates in
Mode 2. If the CTRL pin receives three rising edges,
the IC operates in Mode 3. If the CTRL pin receives
four rising edges, the IC operates in Mode 4.
Mode 1—IC starts up, basic operating mode.
Gain 
R
F

RF 1  RF 2 RF 3
(2)
RF 1  RF 2  RF 3
For example, in figure 1:
RF1 = 20kΩ, RF2 = 20kΩ, RF3 = 120kΩ, RIN = 30kΩ,
therefore, R
F

Mode 3—IC starts up, enable bass enhance function.
If the CTRL pin is pulled to low last at least 200µs, the
IC will be into shutdown mode.
(1)
The RF is given by Equation (2) below:
Mode 2—IC starts up, enable 3D enhance function.
Mode 4—IC starts up, enable 3D and bass enhance
function.
RF  V 
 
R IN  V 
20  20  120
 30 k
20  20  120
30
V 
Gain 
1  
30
V 
Resistor matching is very important in fully differential
amplifiers. The balance of the output on the reference
voltage depends on matched ratios of the resistors.
CMRR, PSRR, and cancellation of the second
harmonic distortion diminish if resistor mismatch
occurs. Therefore, it is recommended to use 1%
tolerance resistors or better to keep the performance
optimized. Matching is more important than overall
tolerance. Resistor arrays with 1% matching can be
used with a tolerance greater than 1%.
Place the input resistors very close to the IS31AP4913
to limit noise injection on the high-impedance nodes.
BASS AUDIO ENHANCEMENT EFFECT
When the bass enhancement is enabled, the low
frequency input signal will be amplified (Figure 8). The
cutoff frequency is fB. The signal below fB will be
enhanced. fB is given by Equation (3):
f
Figure 9
Operating Mode Selected
CHARGE PUMP CONVERTER
IS31AP4913 integrates a charge pump converter to
change input supply voltage (VCC) into a negative
voltage providing a 0V reference for the output.
The charge pump converter only needs three external
components: supply decoupling capacitor, output
bypass capacitor and flying capacitor.
B

1
2 RF 1  RF 2 C B
(3)
For example, in figure 1:
RF1 = 20kΩ, RF2 = 20kΩ, CB = 22nF,
so, f
B

1
 181 Hz
2  20 k  20 k   22 nF
The capacitors should have a tolerance of ±10% or
better, because any mismatch in capacitance causes
an impedance mismatch at the startup frequency and
below.
Choose low ESR capacitors to ensure the best
operating performance and place the capacitors as
close as possible to the IS31AP4913.
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Rev.A, 11/17/2011
7
IS31AP4913
3D AUDIO ENHANCEMENT EFFECT
DESIGN NOTE
The 3D audio enhancement effect can be adjusted by
the resistor, R3D. Decreasing the resistor size will make
the 3D effect more pronounced and decreasing the
capacitor size will raise the cutoff frequency for the
effect.
COMPONENT SELECTION
The cutoff frequency, f3D, is determined by Equation
(4):
f
3D

1
(4)
2R3 D C 3 D
For example, in figure 1:
R3D = 4.7kΩ, C3D = 47nF,
so,
f
3D

1
 721 Hz
2  4.7 k  47 nF
Setting f3D below 1kHz is recommended to get better
3D enhancement.
INPUT CAPACITOR (CIN)
The input capacitors and input resistors form a high
pass filter with the corner frequency, fC, determined in
Equation (5).
1
f 
c 2R C
IN IN
(5)
For example, in figure 1:
RIN = 30kΩ, CIN = 0.47µF,
therefore,
1
f 
 11Hz
c 2  30 k  0 .47 F
The value and ESR of the output capacitor for charge
pump will affect output ripple and transient
performance. A X7R or X5R ceramic capacitor in 2.2μF
is recommended. The flying capacitor should be a
2.2µF X7R or X5R ceramic capacitor.
All capacitors should support at least 10V.
PCB LAYOUT
The decoupling capacitors should be placed close to
the VCC pin and the output capacitors should be
placed close to the VSS pin. The flying capacitor
should be placed close to the CN and CP pins. The
input capacitors and input resistors should be placed
close to the INR and INL pins and the traces must be
parallel to prevent noise. The traces of OUTR and
OUTL pins connected to the headphone should be as
short and wide as possible. The recommended width is
0.5mm.
Trace width should be at least 0.75mm for the power
supply and the ground plane. The thermal pad and the
PGND pin should connect directly to a strong common
ground plane for heat sinking.
The SGND and PGND pins of the IS31AP4913 must
be routed separately back to the decoupling capacitor
in order to provide proper device operation. If the
SGND and PGND pins are connected directly to each
other, the part functions without risk of failure, but the
noise and THD performance will not meet the
specifications.
The value of the input capacitor is important to
consider as it directly affects the bass (low frequency)
performance of the circuit. The capacitors should have
a tolerance of ±10% or better, because any mismatch
in capacitance causes an impedance mismatch at the
corner frequency and below.
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Rev.A, 11/17/2011
8
IS31AP4913
CLASSIFICATION REFLOW PROFILES
Profile Feature
Pb-Free Assembly
Preheat & Soak
Temperature min (Tsmin)
Temperature max (Tsmax)
Time (Tsmin to Tsmax) (ts)
150°C
200°C
60-120 seconds
Average ramp-up rate (Tsmax to Tp)
3°C/second max.
Liquidous temperature (TL)
Time at liquidous (tL)
217°C
60-150 seconds
Peak package body temperature (Tp)*
Max 260°C
Time (tp)** within 5°C of the specified
classification temperature (Tc)
Max 30 seconds
Average ramp-down rate (Tp to Tsmax)
6°C/second max.
Time 25°C to peak temperature
8 minutes max.
Figure 10
Classification Profile
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Rev.A, 11/17/2011
9
IS31AP4913
TAPE AND REEL INFORMATION
Note: All dimensions in millimeters unless otherwise stated.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
10
IS31AP4913
PACKAGING INFORMATION
QFN-20
Note: All dimensions in millimeters unless otherwise stated.
Integrated Silicon Solution, Inc. – www.issi.com
Rev.A, 11/17/2011
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