DS2480B
31 of 31
AC ELECTRICAL CHARACTERISTICS (V
DD
= 4.5V to 5.5V; -40°C to +85°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
UART Bit Time T
T
8.68 104 µs 6
Device Bit Time T
R
8.68 104 µs 6, 7, 16
Fall Time RXD t
FR
8 20 ns 8,17
Rise Time RXD t
RR
13 27 ns 8,17
Transmit Idle Time t
IDLET
0 µs 9
Receive Idle Time t
IDLER
t
IDLET
µs
Asymmetry t
ASYM
1 µs 10
Arrival Response Time t
ARR
4.4 52 µ s 11
Master Reset Time t
MR
104 µs 12
Active Pullup on Time t
APUOT
0.5 2.0 µs 13
Response Time t
RESP
8.68 + D
104 + D
µs 11, 14
NOTES:
1. V
PP
- DV
PROG
must be within 11.5V to 12.0V.
2. Applies only if a 12.0V supply is connected. If V
PP
and V
DD
are tied together, current is less than
1mA.
3. Input load is to GND.
4. Voltage difference between V
DD
and 1-W.
5. Voltage difference between V
PP
and 1-W.
6. 8.68ms (115.2kbps), 52ms (19.2kbps), 17.36ms (57.6kbps), 104ms (9.6kbps).
7. Nominal values; tolerance = ±5%.
8. At V
CC
= 5.0V and 100pF load to GND.
9. See Table 7, Function and Speed Matrix.
10. Independent of baud rate.
11. Minimum at 115.2kbps, maximum at 9.6kbps.
12. The master reset cycle is complete after t
MR
is over.
13. Minimum value at Overdrive speed; maximum value at regular speed.
14. D is the time to complete the activity on the 1-Wire bus; values range from 0 (configuration
command) up to 5130ms (alarming presence pulse).
15. With regular and flexible speed the total capacitive load of the 1-Wire bus should not exceed 20nF,
otherwise the active pullup on threshold V
IAPO
may not be reached in the available time. With
Overdrive speed the capacitive load on the 1-Wire bus must not exceed 1nF.
16. Baud rate calibration is valid at a static V
DD
operating point. Post calibration changes in V
DD
by more
than 5% may cause calibration error to exceed 5%. The DS2480B requires a 1-Wire reset command
sent by the host at a data rate of 9600bps for calibration. Data rates of 115200bps or higher during
calibration may put the DS2480 in an undefined state, requiring a power-down reset to restore normal
operation.
17. Not production tested.
