Rainbow Electronics DS1845 User Manual
Page 12
DS1845
12 of 13
6. A fast mode device can be used in a standard mode system, but the requirement tSU:DAT > 250 ns
must then be met. This will automatically be 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
RMAX
+ tSU:DAT = 1000 + 250 = 1250 ns before the SCL line is
released.
7. After this period, the first clock pulse is generated.
8. The maximum tHD:DAT has only to be met if the device does not stretch the LOW period (tLOW) of
the SCL signal.
9. CB - total capacitance of one bus line in picofarads, timing referenced to (0.9(V
CC
) and (0.1)(V
CC
).
10. EEPROM write begins after a stop condition occurs.
11. Resistor inputs can not go beneath GND by more than 0.5V or above V
CC
by more that 0.5V.
12. The –3 dB cutoff frequency for the DS1845 is 1 MHz (10k/10k version).
13. Absolute linearity is used to measure expected wiper voltage as determined by wiper position. The
DS1845 is specified to provide an absolute linearity of ± 0.5 LSB (10k/10k version), ±1 LSB(10k/50k
version), and ± 1.5 LSB (10k/100k) version.
14. Relative linearity is used to determine the change of wiper voltage between two adjacent wiper
positions. The DS1845 is specified to have a relative linearity of ± 0.25 dB.
15. When used as a rheostat or variable resister the temperature coefficient applies: 650 ppm/°C. When
used as a voltage divider or potentiometer, the effective temperature coefficient approaches
30 ppm/°C.
16. I
CC
specified with SDA pin open.
17. Maximum Icc is dependent on clock rates.
18. Valid for V
CC
= 5V only.
19. Valid at 25°C only.