Single Supply 3V to 7V
Dual Supply ±1.5V to ± 3.5V
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High Signal-to-Noise Ratio 100dB
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High Slew Rate 5V/ µs
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Low Distortion -65dB
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• Output Power at 10% THD+N
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into 8Ω 280mW
into 16Ω 160mW
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• Large Output Voltage Swing
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•Excellent Power Supply Ripple Rejection
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•Flexible Mute Function
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•Integrated Voltage Divider (V
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nate External Resistors
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•Low Power Consumption
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•Short-circuit Elimination
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•Wide Temperature Range
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•No Switch ON/OFF Clicks
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•Available in 8 pin SOP or DIP Package
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/2) to Elimi-
DD
Applications
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•Portable Digital Audio
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Personal Computers
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Microphone Preamplifier
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General Description
The APA4801 is an integrated class AB stereo headphone amplifier contained in an SO-8 or a DIP-8 plastic package with Mute feature . Besides the common
Mute feature , the APA4801 further integrates a voltage divider inside the chip . Thus , the external resistors can be eliminated . The device has been primarily developed for portable digital audio applications .
Block Diagram
Out A
Mute
Input A
1
2
3
MUTE
0dB
0dB
A
+
130k
B
+
Ω
Ω
130k
BIAS
8
7
6
V
DD
Out B
BIAS
V
4
SS
5
Input B
Ordering Information
APA4801
Handling Code
Temp. Range
Package Code
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise
customers to obtain the latest version of relevant information to verify before placing orders.
In the typical application an input capacitor , Ci , is
required to allow the amplifier to bias the input signal
to the proper DC level for optimum operation . In this
case , the external capacitor Ci and the internal resistance Ri form a high-pass filter with the corner frequency determined in the follow equation :
fc (highpass)= 1/ (2πRiCi)(1)
The value of Ci is important to consider as it directly
affects the low frequency performance of the circuit .
Consider the APA4801 where Ri is 130kΩ internal
fixed . Equation is reconfigured as follow :
Ci= 1/(2π*130kΩ*fc)(2)
And the ceramic capacitor is recommanded
Bias Capacitor, Cb
As with any power amplifier , proper supply bypassing is critical for low noise performance and high
power supply rejection . The capacitor location on
both the bypass and power supply pins should be as
close to the device as possible . The effect of a larger
half supply bias capacitor is improved PSRR due to
increased half-supply stability . Typical applications
employ a 5V regulator with 10µF and a 0.1µF bias
capacitors which aid in supply filtering . This does
not eliminate the need for bypassing the supply nodes
of the APA4801 . The selection of bias capacitors ,
especially Cb , is thus dependent upon desired PSRR
requirements , click and pop performance . The capacitor is fed from a 50kΩ source inside the amplifier.
To keep the start-up pop as low as possible , the
relationship shown in equation should be maintained.
1/(Cb*50kΩ)≤ 1/{Ci*Ri}(3)
As an example , consider a circuit where Cb is
4.7µF , Ci is 1µF and Ri is 130kΩ . Inserting these
values into the equation we get 4.26≤ 7.69 which
satisfies the rule . Bias capacitor , Cb , values of
2.2µF to 10µF ceramic or tantalum low-ESR capacitors are recommended for the best THD and noise
performance.
Output Coupling Capacitor, Cc
In the typical single-supply SE configuration , an output coupling capacitor (Cc) is required to block the
DC bias at the output of the amplifier thus preventing
DC currents in the load . As with the input coupling
capacitor , the output coupling capacitor and impedance of the load form a high-pass filter governed by
equation .
fc(highpass)= 1/(2πR
Cc)(4)
L
For example , a 220µF capacitor with an 32Ω speaker
would attenuate low frequencies below 22Hz . The
main disadvantage , from a performance standpoint,
is the load impedance is typically small , which drives
the low-frequency corner higher degrading the bass
response . Large values of Cc are required to pass
low frequencies into the load .
Optimizing Depop Circuitry
When the amplifier is in mute mode , both of the output stage and input bypass continues to be biased .
And no pop noise will be heard during the transition
out of mute mode .
Power Supply Decoupling , Cs
APA4801 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling
to ensure the output total harmonic distortion (THD)
is as low as possible . Power supply decoupling also
prevents the oscillations causing by long lead length
between the amplifier and the speaker . The optimum
decoupling is achieved by using two different type
capacitors that target on different type of noise on
the power supply leads . For higher frequency transients , spikes , or digital hash on the line , a good
low equivalent-series-resistance (ESR) ceramic capacitor , typically 0.1µF placed as close as possible
to the device V
frequency noise signals , a large aluminum electro-
lead works best . For filtering lower-
DD
lytic capacitor of 10µF or greater placed near the audio
power amplifier is recommended .
Terminal MaterialSolder-Plated Copper (Solder Material : 90/10 or 63/37 SnPb
Lead SolderabilityMeets EIA Specification RSI86-91, ANSI/J-STD-002 Category 3.
Packaging2500 devices per reel
Reflow Condition(IR/Convection or VPR Reflow)
Reference JEDEC Standard J-STD-020A APRIL 1999
Peak temperature
temperature
Pre-heat temperature
°
183 C
Time
Classificatio n R e flow Profiles
Convection or IR/
Convection
Average ramp-up rate(183°C to Peak)3°C/second max.10 °C /second max.
Preheat temperature 125 ± 25°C)
Temperature maintained above 183°C
Time within 5°C of actual peak temperature
Peak temperature range
Ramp-down rate
Time 25°C to peak temperature
120 seconds max
60 – 150 seconds
10 –20 seconds60 seconds
220 +5/-0°C or 235 +5/-0°C215-219°C or 235 +5/-0°C
6 °C /second max.10 °C /second max.
6 minutes max.
VPR
Package Reflow Conditions
pkg. thickness ≥≥≥≥ 2.5mm
and all bgas
Convection 220 +5/-0 °CConvection 235 +5/-0 °C
VPR 215-219 °CVPR 235 +5/-0 °C
IR/Convection 220 +5/-0 °CIR/Convection 235 +5/-0 °C