M41T00AUD Datasheet, PDF (1/44 Pages) STMicroelectronics – Serial real-time clock with audio

M41T00AUD
Serial real-time clock with audio
Features
■ Combination real-time clock with audio
– Serial RTC based on M41T00
– Audio section provides:
– 300mW differential audio amplifier
– 256 and 512Hz tone generation
– -33 to +12dB gain, 3dB steps (16 steps
plus MUTE)
■ Real-time clock details:
– Superset of M41T00
– 3.0 to 3.6V operation
– Timekeeping down to 1.7V
– Automatic backup switchover circuit
– Ultra low 400nA backup current at 3.0V
(typ)
– Suitable for battery or capacitor backup
– On-chip trickle charge circuit for backup
capacitor
– 400kHz I²C bus
– M41T00 compatible register set with
counters for seconds, minutes, hours, day,
date, month, years, and century
– Automatic leap year compensation
– HT bit set when clock goes into backup
mode
– RTC operates using 32,768Hz quartz
crystal
– Calibration register provides for
adjustments of -63 to +126ppm
– Oscillator supports crystals with up to
40kΩ series resistance, 12.5pF load
capacitance
– Oscillator fail detect circuit OF bit indicates
when oscillator has stopped for four or
more cycles
DFN16 (5mm x 4mm)
“D” Suffix
■ Audio section
– Power amplifier
– Differential output amplifier
– Provides 300mW into 8Ω (THD+N = 2%
(max), f_in = 1kHz)
– Summing node at audio input
– Inverting configuration with summing
resistors into the minus (-) terminal
– 0dB gain with 10kΩ feedback resistor
and 20kΩ input summing resistors
– Signal input centered at V_DD/2
– 1.6V_P-P analog input range (max)
– 256 or 512 Hz signal multiplexing with
analog input to provide audio with beep
tones
– Volume control, 4-bit register
– Allows gain adjustment from -33dB to
+12dB
– 3dB steps
– MUTE bit
– Audio automatically shuts off in backup
mode
■ 0°C to 70°C operation
■ Small DFN16 package (5mm x 4mm)
December 2007
Rev 2
1/44
www.st.com
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