Rainbow-electronics DS1340 Bedienungsanleitung PDF herunterladen (Seite 4)

DS1340

2-Wire RTC with Trickle Charger

4 _____________________________________________________________________

POWER-UP/POWER-DOWN CHARACTERISTICS

= -40°C to +85°C) (Figure 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Recovery at Power-Up t

REC

(Note 17) 2 ms

Fall Time; V

PF(MAX)

PF(MIN)

VCCF

300

µs

Rise Time; V

PF(MIN)

PF(MAX)

VCCR

0µs

WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed when device is in battery-backup mode.

Note 1: Limits at -40°C are guaranteed by design and not production tested.

Note 2: After this period, the first clock pulse is generated.

Note 3: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to as the V

IH(MIN)

of the SCL

signal) to bridge the undefined region of the falling edge of SCL.

Note 4: The maximum t

HD:DAT

only has to be met if the device does not stretch the low period (t

LOW

) of the SCL signal.

Note 5: A fast-mode device can be used in a standard-mode system, but the requirement t

SU:DAT

≥ to 250ns must be met. This

is automatically the case if the device does not stretch the low period of the SCL signal. If such a device does stretch the

low period of the SCL signal, it must output the next data bit to the SDA line t

R MAX

+ t

SU:DAT

= 1000 + 250 = 1250ns

before the SCL line is released.

Note 6: C

—total capacitance of one bus line in pF.

Note 7: The parameter t

OSF

is the period of time the oscillator must be stopped for the OSF flag to be set over the 0V ≤ V

≤

CCMAX

and 1.3V ≤ V

BAT

≤ 3.7V range.

Note 8: All voltages are referenced to ground.

Note 9: Measured at V

= typ, V

BACKUP

= 0V, register 08h = A5h.

Note 10: The use of the 250Ω trickle-charge resistor is not allowed at V

> 3.63V and should not be enabled.

Note 11: Measured at V

= typ, V

BACKUP

= 0V, register 08h = A6h.

Note 12: Measured at V

= typ, V

BACKUP

= 0V, register 08h = A7h.

Note 13: I

CCA

—SCL clocking at max frequency = 400kHz.

Note 14: Specified with 2-wire bus inactive.

Note 15: Measured with a 32.768kHz crystal attached to the X1 and X2 pins.

Note 16: Limits at +25°C are guaranteed by design and not production tested.

Note 17: This delay applies only if the oscillator is enabled and running. If the oscillator is disabled or stopped, no power-up delay

occurs.

SDA

SCL

HD:STA

LOW

HIGH

BUF

HD:DAT

SU:DAT

REPEATED

START

SU:STA

HD:STA

SU:STO

STOP START

Figure 1. Data Transfer on 2-Wire Serial Bus

1 2 3 4 5 6 7 8 9 10 11 12

Kommentare zu diesen Handbüchern

Keine Kommentare

Rainbow-electronics DS1340 Bedienungsanleitung Seite 4

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Computerhardware Rainbow-electronics DS1340