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Description
The PAM8615 is a 16W 32W (per channel) efficient Class-D audio
power amplifier for driving stereo speakers in a single-ended
configuration or mono bridge-tied speaker. The PAM8615 can drive
single-ended speakers as low as 4Ω. Due to the low power
dissipation and high efficiency the device can be used without any
external heat sink when playing music.
Stereo speaker volume is controlled with a DC voltage applied to the
volume control terminal offering a range of gain from -40dB to +36dB.
The PAM8615 is available in a TSSOP-24 package.
Features
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PAM8615
16W/ 32W STEREO CLASS-D AUDIO POWER AMPLIFIER
Pin Assignments
• 32W/ch into 8Ω BTL Load from 24V Supply (Thermal Limited)
• 16W/ch into 4Ω SE Load from 24V Supply (Thermal Limited)
• Operates from 8V to 30V
• Supports Multiple Output Configurations:
2-Ch Single-ended (half bridge)(16WX2)
1 Ch Bridge-tied load (full bridge) (32WX1)
• High Efficiency Above 90%
• 64-Setup DC Volume Control from -40dB to +36dB
• Singel Ended Analog Inputs
• Thermal and Short-Circuit Protection
• Flexible Frequency Adjustable by External Component
• Clock Output for Synchronization with Multiple Class-D Devices
• No Pop Noise for Start-Up and Shut-Down Sequences
• Space-Saving Surface-Mount 24 Pin TSSOP Package
• Pb-Free Package
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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Applications
• Televisions
• Home Sound Systems
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Typical Applications Circuit
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PAM8615
Single-Ended Configuration
PAM8615
Document number: DSxxxxx Rev. 1 - 1
BTL Configuration
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Pin Descriptions
Pin
Number
1 OUT_A O
2 PVCC_A P
3 SHDN I
4 MUTE I
5 IN_A I
6 DGND P
7 IN_B I
8 VCM O
9 DCV I
10 MS_SV I
11 PVCC_B P
12, 13 OUT_B O
14 PGND_B P
15 BST_B I/O
16 VCLAMP P
17 STNC I/O
18 AGND P
19 ROSC I/O
20 AVDD P
21 AVCC P
22 BST_A I/O
23 PGND_A P
PAM8615
Document number: DSxxxxx Rev. 1 - 1
Pin
Name
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PAM8615
I/O/P Function
H-bridge A output.
Power supply for H-bridge A not connected to PVCC_B or AVCC.
Shutdown signal for IC (low = shutdown, high = operat ional). TTL logic levels with compliance to AVCC.
Alogic high on this pin disables the outputs. A low on this pin enables the outputs. TTL logic levels with
compliance to AVCC.
Audio input for channel A.
Digital GND
Audio input for channel B.
Reference for analog cells.
DC voltage setting the gain of the amplifier.
Master/Slave select for determining direction of SYNC terminal. High = Master mode, SYNC terminal is an
output; Low = Slave mode, SYNC terminal accept s a clock input.
Power supply for H-bridge B, not connected to PVCC_A or AVCC
H-bridge B output
Power ground for H-bridge B
Bootstrap I /O for H-bridge B high-side FET
Internally generated voltage supply for bootst rap. Not to be used as a supply or connected to any component
other than the decoupling capacitor.
Clock i nput/output for synchroni zing multiple class-D devices. Direction determined by MS_SV terminal.
Analog GND.
Current s etting resis tor for ramp generator.
Analog 5V Regulated output.
High-voltage analog power supply.
Bootstrap I /O for H-bridge A high-side FET.
Power ground for H-bridge A.
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Functional Block Diagram
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PAM8615
Absolute Maximum Ratings (@T
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability. All voltages are with respect to ground.
Parameter Rating Unit
Supply Voltage AVCC, PVCC -0.3 to +30 V
Logic Input Voltage:
SHDN, MUTE -0.3 to AVCC +0.3
DCV, MS_SV, SYNC 0 to +5.5
Analog Input Voltage:
IN-A, IN-B 0 to +5.5 V
Storage Temperature -65 to +150
Soldering Temperature 300, 5sec
PAM8615
Document number: DSxxxxx Rev. 1 - 1
= +25°C, unless otherwise specified.)
A
V
°C
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PAM8615
Recommended Operating Conditions (@T
= +25°C, unless otherwise specified.)
A
Parameter Rating Unit
Supply Voltage (VCC)
DCV Volume Control Pin 0 to 5
f
Oscillator Frequency (R
OSC
= 100kΩ)
OSC
TA – Operating Free-Air Temperature
Ambient Operating Temperature -20 to +85
Ambient Temperature Range -40 to +160
10 to 26
V
250 to 350 kHz
-40 to +85
°C
Junction Temperature Range -40 to +85
Thermal Information
Parameter Package Symbol Max Unit
Thermal Resistance (Junction to Ambient) TSSOP-24
θ
JA
Electrical Characteristics (@T
= +25°C, VCC = 24V, Gain = 20dB, RL = 4Ω, unless otherwise specified.)
A
Parameter Symbol Test Conditions Min Typ Max Units
Class-D Output Offset Voltage (measured differently) |VOS|
Quiescent Supply Current
Quiescent Supply Current in Mute Mode
Quiescent Supply Current in Shutdown Mode
Oscillator Frequency
Drain-Source On-State Resistance
I
CC
I
CC(MUTE)
I
CC(SD)
f
OSC
R
DS(ON)
Power Supply Rejection Ratio PSRR
Output Power at 1% THD+N
P
(SE)
O
Output Power at 10% THD+N
Output Power at 1% THD+N
(BTL)
P
O
Output Power at 10% THD+N
Total Harmonic Distortion + Noise THD+N
Output Integrated Noise Floor
Crosstalk
V
C
Signal-to-Noise Ratio SNR
V
= 0V, AV = 36dB
I
SHDN = 2V, MUTE = 0V, Input
AC_GND, No load
MUTE = 2V, No load
SHDN = 0.5V, No load 5 20 µA
R
V
= 100kΩ
OSC
= 24V,IO = 1A, TA = 27°C
CC
V
= 23.5V to 24.5V
CC
= 24V, RL = 4Ω, f = 1kHz
V
CC
VCC = 24V, RL = 8Ω, f = 1kHz
V
= 24V, RL = 4Ω, f = 1kHz
CC
VCC = 24V, RL = 8Ω, f = 1kHz
= 24V, RL = 8Ω, f = 1kHz
V
CC
VCC = 12V, RL=8Ω, f = 1kHz
V
= 24V, RL = 8Ω, f = 1kHz
CC
VCC = 12V, RL = 8Ω, f = 1kHz
R
= 4Ω, f = 1kHz, Po = 10W
L
RL = 8Ω, f = 1kHz, Po = 5W
20Hz to 22kHz, A-weighted
N
filter, Gain = 20dB
PO = 1W, f = 1kHz, Gain = 20dB
S
Max output at THD+N<1%,
f = 1kHz, Gain = 20dB
Thermal Trip Point 160 °C
Thermal Hystersis 40 °C
30 °C/W
10 65 mV
25 40 mA
25 40 mA
323 kHz
220 mΩ
-60 dB
14
8.2
17.3
9.8
27
7
35
9
0.25%
0.15%
-67 dBV
-60 dB
86 dB
W
W
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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PAM8615
DC Volume Control
VOLTAGE OF THE
STEP
1 0.10 -60 33 2.34 17.4
2 0.17 -40 34 2.41 18.0
3 0.24 -30 35 2.48 18.6
4 0.31 -20 36 2.55 19.2
5 0.38 -10 37 2.62 19.8
6 0.45 -5 38 2.69 20.4
7 0.52 -2.5 39 2.76 21.0
8 0.59 0 40 2.83 21.6
9 0.66 2 41 2.90 22.2
10 0.73 3 42 2.97 22.8
11 0.80 4 43 3.04 23.4
12 0.87 4.8 44 3.11 24.0
13 0.94 5.4 45 3.18 24.6
14 1.01 6.0 46 3.25 25.2
15 1.08 6.6 47 3.32 25.8
16 1.15 7.2 48 3.39 26.4
17 1.22 7.8 49 3.46 27.0
18 1.29 8.4 50 3.53 27.6
19 1.36 9.0 51 3.60 28.2
20 1.43 9.6 52 3.67 28.8
21 1.50 10.2 53 3.74 29.4
22 1.57 10.8 54 3.81 30.0
23 1.64 11.4 55 3.88 30.6
24 1.71 12.0 56 3.95 31.2
25 1.78 12.6 57 4.02 31.8
26 1.85 13.2 58 4.09 32.4
27 1.92 13.8 59 4.16 33.0
28 1.99 14.4 60 4.23 33.6
29 2.06 15.0 61 4.30 34.2
30 2.13 15.6 62 4.37 34.8
31 2.20 16.2 63 4.44 35.4
32 2.27 16.8 64 4.51 36.0
VOLUME
(V) (dB) (V) (dB)
PAM8615
Document number: DSxxxxx Rev. 1 - 1
TOTAL_GAIN
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STEP
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VOLTAGE OF THE
VOLUME
TOTAL_GAIN
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Typical Performance Characteristics (@T
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= +25°C, VDD = 24V, RL = 8Ω, unless otherwise specified.)
A
PAM8615
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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Typical Performance Characteristics (cont.) (@T
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= +25°C, VDD = 24V, RL = 8Ω, unless otherwise specified.)
A
PAM8615
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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Test Setup for Performance Testing
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PAM8615
Notes: 1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer.
2. Two 22μH inductors are used in series with load resistor to emulate the small speaker for effic iency measurement.
Application Information
Power and Heat Dissipation
Choose speakers that are able to stand large output power from the PAM8615. Otherwise, speaker may suffer damage.
Heat dissipation is very important when the device works in full power operation. Two factors affect the heat dissipation, the efficiency of the
device that determines the dissipation power, and the thermal resistance of the package that determines the heat dissipation capability.
Generally, Class–D amplifiers are high efficiency and need no heat sink. For high power ones that has high dissipation power, the heat sink may
also not necessary if the PCB is carefully designed to achieve good heat dissipation by the PCB itself.
Dual-Side PCB
To achieve good heat dissipation, the PCB's copper plate should be thicker than 35µm and the copper plate on both sides of the PCB should be
utilized for heat sink.
The thermal pad on the bottom of the device should be soldered to the plate of the PCB, and via holes, usually 9 to 16 should be drilled in the
PCB area under the device and deposited copper on the vias should be thick enough so that the heat can be dissipated to the other side of the
plate. There should be no insulation mask on the other side of the copper plate. It is better to drill more vias on the PCB around the device if
possible.
Volume Control
A DC volume control section is integrated in PAM8615, controll ing via DCV and DGND terminals. The voltage on DCV pin, determines internal
amplifier gain as listed in Page 6.
If a resistor divider is used to fix gain of the amplifier, the DCV terminal can be directly connected to the resistor divider connected across AVDD
and DGND. For fixed gain, the resistor divider values are calculated to center the voltage given in Page 6.
MUTE Operation
The MUTE pin is an input for controlling the output state of the PAM8615. A logic high on this pin disables the outputs and low enables the
outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade.
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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PAM8615
Application Information (cont.)
Shutdown Operation
The PAM8615 employs a shutdown operation mode to reduce supply current to the absolute minimum level during periods of non-use to save
power. The SD input terminal should be pull high during normal operation when the amplifier is in use. Pulling SD low causes the outputs to mute
and the amplifier to enter a low-current state. SD should never be left unconnected to prevent the amplifier from unpredictable operation.
For the best power-off pop performance, the amplifier should be set in shutdown mode prior to removing the power supply voltage.
Internal Bias Generator Capacitor Selection
The internal bias generator (VCM) provides the internal bias for the preamplifier stage. The external input capacitors and this internal reference
allow the inputs to be biased within the optimal common-mode range of the input preamplifiers.
The selection of the capacitor value on the VCM terminal is critical for achieving the best device performance. During startup or recovery from
shutdown state, the VCM capacitor determines the rate at which the amplifier starts up. The startup time is not critical for the best de-pop
performance since any heard pop sound is the result of the class-D output switching-on other than that of the startup time. However, at least a
0.47μF capacitor is recommended for the VCM capacitor.
Another function of the VCM capacitor is to bypass high frequency noise on the internal bias generator.
Power Supply Decoupling, CS
The PAM8615 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic
distortion (THD) as low as possible. Power supply decoupling also prevents oscillations caused by long lead between the amplifier and the
speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply
leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-seriesresistance (ESR) ceramic capacitor,
typically 0.1μF, is recommended, placing as close as possible to the device's PVCC lead. To filter lower-frequency noises, a large aluminum
electrolytic capacitor of 470μF or greater is recommended, placing near the audio power amplifier. The 10μF capacitor also serves as a local
storage capacitor for supplying current during large signal transients on the amplifier outputs.
Selection of ROSC
The switching frequency is determined by the values of components connected to ROSC (pin 19) and calculated with the following equation:
The recommended values is R
BST_A and BST_B Capacitors
The half H-bridge output stages use NMOS transistors only. They therefore require bootstrap capacitors for the high side of each output to turn
on correctly. An at least 220nF ceramic capacitor, rated for at least 25V, must be connected from each output to its corresponding bootstrap
input. Specifically, one 220nF capacitor must be connected from OUT_A to BST_A, and another 220nF capacitor from OUT_B to BST_B. It is
recommended to use 1µF BST capacitor to replace 220nF for lower than 100Hz applications.
=
f
OSC
VCLAMP Capacitors
To ensure that the maximum gate-to-source voltage for the NMOS output transistors not exceeded, two internal regulators are used to clamp the
gate voltage. A 1μF capacitors must be connected from VCLAMP to ground and must be rated for at least 25V. The voltages at the VCLAMP
terminals vary with VCC and may not be used to power any other circuitry.
Internal Regulated 5-V Supply (AVDD)
The AVDD terminal is the output of an internallygenerated 5V supply, used for the oscillator, preamplifier, and volume control circuitry. It requires
a 0.1μF to 1μF capacitor, placed very close to the pin to Ground to keep the regulator stable. The regulator may not be used to power any
external circuitry.
PAM8615
Document number: DSxxxxx Rev. 1 - 1
68.0
F
x
21
R
pOSC
= 100KΩ for a switching frequency of 323kHz.
OSC
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Application Information (cont.)
Using low-ESR Capacitors
Low - ESR capacitors are recommended throughout this application section. A real (with respect to ideal) capacitor can be modeled simply as a
resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The
lower the equivalent value of this resistance the more the real capacitor behaves as an ideal capacitor.
Short-Circuit Protection
The PAM8615 has short circuit protection circuitry on the outputs to prevent damage to the device when output-to-output shorts (BTL mode),
output-to- GND shorts, or output-to-VCC shorts occur. Once a short-circuit is detected on the outputs, the output drive is immediately disabled.
This is a latched fault and must be reset by cycling the voltage on the SD pin to a logic low and back to the logic high state for normal operation.
This will clear the short-circuit flag and allow for normal operation if the short was removed. If the short was not removed, the protection circuitry
will again activate.
Thermal Protection
Thermal protection on the PAM8615 prevents damage to the device when the internal die temperature exceeds +160°C. There is a ±15 degree
tolerance on this trip point from device to device. Once the die temperature exceeds the set thermal point, the device enters into the shutdown
state and the outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by +40°C.
The device begins normal operation at this point without external system intervention.
Master-Slave and SYNC Operation
The MS/SL and SYNC terminals can be used to synchronize the frequency of the class-D output switching. When the MS/SL is high or left
floating due to the internal pull up resistor, the switching frequency is determined by the ROSC. The SYNC becomes an output whose
source/sink current is about 0.5mA, and the frequency of this output is also determined by the ROSC. And this output can be connected to
another PAM8615 who is configured in the slave mode. The output switching is synchronized to avoid any beat frequencies that occur in the
audio band when two Class-D amplifiers in the same system are switching at the slight different frequencies. When the MS/SL is low, the
switching frequency is determined by the incoming square wave on the SYNC input. The SNYC becomes an input in this mode and accept a
square wave from another PAM8615 configured in the master mode or from an external GPIO.
(Key: MS/SL = ”H”, Master Mode, MS/SL = ”L”, Slave Mode)
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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Ordering Information
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PAM8615
Marking Information
PAM8615
Document number: DSxxxxx Rev. 1 - 1
Part Number Package Type Standard Package
PAM8615RHR TSSOP-24 3000 Units/Tape & Reel
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Package Outline Dimensions (All dimensions in mm.)
TSSOP-24
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PAM8615
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
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IMPORTANT NOTICE
LIFE SUPPORT
PAM8615
Document number: DSxxxxx Rev. 1 - 1
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