M41T00AUD_12 STMICROELECTRONICS [STMicroelectronics], M41T00AUD_12 Datasheet - Page 6

• Manufacturer Part Number: M41T00AUD_12
• Description: Serial real-time clock (RTC) with audio
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Description
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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 300 mW 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 8 kHz low-pass filter follows that with a 16-step
programmable gain stage next. A 256 or 512 Hz audio tone can be switched into the filter in
place of the input signal. From the gain stage, the 300 mW 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 32.768 kHz 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 byte to be transferred.
Typical data retention times will be in excess of 5 years with a 50 mAh 3 V lithium cell (see
RTC DC characteristics,
Figure 1.
Logic diagram
Table
2) are accessed over a 400 kHz I
Table 12
V BACK
OSCO
OSCI
SDA
SCL
AIN
Doc ID 13480 Rev 5
for more information).
M41T00AUD
V SS
V CC
CC
2
is removed. Backup power can be
C bus. The address register
NC
V BIAS
IRQ/FT/OUT
FBK
AOUT+
AOUT –
ai13322
M41T00AUD