M41T00AUDD1E STMICROELECTRONICS [STMicroelectronics], M41T00AUDD1E Datasheet - Page 6

• Manufacturer Part Number: M41T00AUDD1E
• Description: Serial real-time clock with audio
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

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Description
The M41T00AUD is a low power serial real-time clock (RTC) with an integral audio section
with tone generator and 300mW output amplifier. The RTC is a superset of the M41T00 with
enhancements such as a precision reference for switchover, an oscillator fail detect circuit
and storing of the time at power down. The audio section includes a summing amplifier
(inverting) at the input. An 8kHz low pass filter follows that with a 16 step programmable gain
stage next. A 256 or 512Hz audio tone can be switched into the filter in place of the input
signal. From the gain stage, the 300mW amplifier drives the output pins.
The M41T00AUD has a built-in power sense circuit which detects power failures and
automatically switches to the backup input when V
supplied by a capacitor or by a battery such as a Lithium coin cell. The device includes a
trickle charge circuit for charging the capacitor.
The RTC includes a built-in 32.768kHz oscillator controlled by an external crystal. Eight
register bytes are used for the clock/calendar functions and are superset compatible with
the M41T00. Two additional registers control the audio section and the trickle charger. The
10 registers (see
increments automatically after each byte READ or WRITE operation thus streamlining
transfers by eliminating the need to send a new address for each by to be transferred.
Typical data retention times will be in excess of 5 years with a 50mAh 3V lithium cell (see
RTC DC characteristics,
Figure 1.
Logic diagram
Table
V BACK
OSCO
OSCI
SDA
SCL
2) are accessed over a 400kHz I
AIN
Table 12
for more information).
M41T00AUD
V SS
V CC
CC
is removed. Backup power can be
NC
V BIAS
IRQ/FT/OUT
FBK
AOUT+
AOUT –
2
C bus. The address register
ai13322