Description
The M41T00AUD is a low power serial real-time clock (RTC) with an integral audio section with tone generator and 300mW output amplifier.
   
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
■ Audio section
    – Power amplifier
        – Differential output amplifier
        – Provides 300mW into 8Ω (THD+N = 2%
            (max), fin = 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 VDD/2
        – 1.6VP-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)