Preliminary Product Brief
H i g h E n d St e r e o A u d i o C o d e c w i t h S y s t e m P M U
General Description
Key Features
The AS3543 is an ultra low power stereo audio codec
and is designed for Portable Digital Audio Applications.
It allows high-end quality playback with up to 100dBA
SNR and recording in FM quality. With one microphone
(including pre-amplifier and supply for an electret microphone) and two line inputs, it allows connecting a variety
of audio inputs. The different audio signals can be mixed
via a 6-channel mixer and fed to either a headphone output for 16 /32 headsets or a line output. Both outputs
have a ground noise cancellation to use it e.g. in car
docking stations. The audio outputs have also an auto
fading implemented which performs the fade-in, fadeout as well as the transition between specific volume
levels automatically with an selectable timing.
Further the device offers advanced power management
functions. All necessary ICs and peripherals in a Digital
Audio Player are supplied by the AS3543. It features 2
DCDC converters for core and memory/periphery supply
as well as 4 LDOs. Both DCDC converter feature DVM
(dynamic voltage management) with an selectable timing for the voltage stepping. The different regulated supply voltages are programmable via the serial control
The step-up converter for the backlight can operate up
to 25V (with an external transistor even higher) in voltage and current control mode. An internal voltage protection is limiting the output voltage in the case of
external component failures. 2 high voltage current sinks
can be used to operate two , if needed also unbalanced,
LED strings. An automatic dimming function allows a
logarithmic on/off of the backlight with selectable timing.
AS3543 also contains a Li-Ion battery charger with constant current, constant voltage and trickle charging. The
maximum charging current is 460mA. An integrated battery switch is separating the battery during charging or
whenever an external power supply is present. With this
switch it is also possible to operate with no or deeply discharged batteries.
The AS3543 has an on-chip, phase locked loop (PLL)
which generates the needed internal CODEC master
clock. I2S Frame and shift-clock have to be applied from
the processor for playback and recording.
Audio power consumption:
- 5mW: 96dB DAC to Headphone @ 1.8V, 32Ω
- 7mW: 100dB DAC to Headphone @ 2.9V, 32Ω
Sigma Delta Converters
- 98dB SNR ('A' weighted) @ 1.8V
- 102dB SNR ('A' weighted) @ 2.9V
- 83dB SNR ('A' weighted) @ 1.8V
Sampling Frequency
- DAC: 8-48kHz
- ADC: 8-24kHz
High Efficiency Headphone Amplifier
volume control via serial interface
32 steps @1.5dB and MUTE
2x12mW @16 driver capability@ 1.8V supply
THD -74dB @16Ω; 1.8V
2x40mW @16 driver capability@ 2.9V supply
THD -77dB @16Ω; 2.9V
headphone and over-current detection
phantom ground eliminates large capacitors
ground noise cancellation
Line Output
volume control via serial interface
32 steps @1.5dB and MUTE
0.6Vp @10kΩ
ground noise cancellation
Further the AS3543 has an independent 32kHz real time
clock (RTC) on chip which allows a complete power
down of the system CPU while only consuming less than
1µA. An internal switch automatically switches between
the RTC backup-battery and main battery supply.
The single supply voltage may vary from 2.7V (2.4V) to
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Preliminary Product Brief -
Microphone Input
3 gain pre-setting (28dB/34dB/40dB) and AGC
2 gain steps @1.5dB and MUTE
supply for electret microphone
microphone detection
remote control by switch
automatic battery monitoring with interrupt generation and selectable warning level
automatic temperature monitoring with interrupt
generation and selectable warning and shutdown
2 Line Inputs
volume control via serial interface
32 steps @1.5dB and MUTE
stereo or 2x mono
Audio Mixer
6 channel input/output mixer with AGC
mixes line inputs abd microphone with DAC
left and right channels independent
Power Management
Voltage Generation
Real Time Clock
ultra low power 32kHz oscillator
32bit RTC sec counter, 96 days auto wake-up
selectable alarm (seconds or minutes)
128bit free SRAM for random settings
32kHz clock output to peripheral
voltage generation
trim able oscillator
<1uA total power consumption
Auxiliary Oscillator (system clock generation)
step down for CPU core (0.61V-3.35V, 250mA)
low power 12-24MHz oscillator
step down for peripheral (0.61V-3.35V, 250mA)
clock output
LDO1 for AFE supply (1.7V (1.65-3.2V), 50mA)
General Purpose ADC
LDO2 for AFE supply (2.7V (2.3-3.5V), 200mA)
10bit resolution
LDO3 for peripherals (1.2V-3.5V, 100/200mA)
19 inputs analog multiplexer
LDO4 for peripherals (1.2V-3.5V, 100/200mA)
VBUS comparator
2 wire serial control interface
separate input for LDO3
reset pin with selectable delay, power good pin
power supply supervision & hibernation modes
64bit unique ID (OTP)
5sec and 10sec emergency shut-down
22 different interrupts
Backlight Driver
Package CTBGA68 [6.0x6.0x1.1mm] 0.5mm pitch
step up for backlight (25V)
current control mode (1.2-36mA)
voltage control mode
2 current sinks
automatic dimming
Portable Digital Audio/Video Player and Recorder
PDA, Smartphone
over-voltage protection
Battery Charger
automatic trickle charge (55mA)
prog. constant current charging (55-460mA)
prog. constant voltage charging (3.9V-4.25V)
current limitation for USB mode
integrated battery switch
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Figure 1. Block Diagram
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Preliminary Product Brief -
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