M48T59 datasheet(5/21 Pages) STMICROELECTRONICS

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M48T59, M48T59Y, M48T59V

Table 8. Power Down/Up AC Characteristics

(TA = 0 to 70 °C or –40 to 85 °C)

Note: 1. VPFD (max) to VPFD (min) fall time of less than tF may result in deselection/write protection not occurring until 200µs after VCC pass-

es VPFD (min).

2. VPFD (min) to VSS fall time of less than tFB may cause corruption of RAM data.

3. tREC (min) = 20ms for industrial temperature grade 6 device.

Symbol

Parameter

Min

Max

Unit

tPD

E or W at VIH before Power Down

µs

(1)

VPFD (max) to VPFD (min) VCC Fall Time

300

µs

tFB

(2)

VPFD (min) to VSS VCC Fall Time

M48T59/Y

µs

M48T59V

150

µs

VPFD (min) to VPFD (max) VCC Rise Time

µs

tRB

VSS to VPFD (min) VCC Rise Time

1µs

tREC

(3)

VPFD (max) to RST High

200

Figure 5. Power Down/Up Mode AC Waveforms

AI03258

VCC

INPUTS

RST

OUTPUTS

DON'T CARE

HIGH-Z

tFB

tREC

tRB

tDR

VALID

VPFD (max)

VPFD (min)

VSO

tPD

RECOGNIZED

(PER CONTROL INPUT)

The SOIC and battery/crystal packages are

shipped separately in plastic anti-static tubes or in

Tape & Reel form. For the 28 lead SOIC, the bat-

tery/crystal package (i.e. SNAPHAT) part number

is "M4T28-BR12SH" or “M4T32-BR12SH”.

Caution: Do not place the SNAPHAT battery/crys-

tal top in conductive foam, as this will drain the lith-

ium button-cell battery.

As Figure 3 shows, the static memory array and

the quartz controlled clock oscillator of the

M48T59/59Y/59V are integrated on one silicon

chip.

The two circuits are interconnected at the upper

eight memory locations to provide user accessible

BYTEWIDE™ clock information in the bytes with

addresses 1FF8h-1FFFh. The clock locations

contain the century, year, month, date, day, hour,

minute, and second in 24 hour BCD format (except

for the century). Corrections for 28, 29 (leap year),

30, and 31 day months are made automatically.

Byte 1FF8h is the clock control register. This byte

controls user access to the clock information and

also stores the clock calibration setting.

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