am79r251 Advanced Micro Devices, am79r251 Datasheet - Page 24

• Manufacturer Part Number: am79r251
• Description: Intelligent Subscriber Line Interface Circuit Islic
• Manufacturer: Advanced Micro Devices

TIMING SPECIFICATIONS
24
Notes:
1. The P1
2. After a power-on reset or hardware reset, the relay outputs from the Am79R251 turn all relays off. An
3. When writing to the ISLIC registers, the sequence is:
4. Am79R251 registers are refreshed at 5.33 kHz when used with an ISLAC device.
5. If the clock or MPI becomes disabled, the LD pins and P1
6. Not tested in production. Guaranteed by characterization.
trSLD
tfSLD
tSLDPW
tSDXSU
tSDXHD
tSDXD
Symbol
unassuming state is to place the relay control pins, which are level triggered, to a reset state for all relays.
Any noise encountered only raises the levels toward the register lock state.
a. Set LD pin to mid-state
b. Place appropriate data on the P1
c. Assert the LD pin to High or Low to write the proper data
d. Return LD pin to mid-state
Am79R251 and the line connection.
–
3 pins are updated continuously during operation by the LD signal.
LD
LD
LD
P1,P2,P3
P1,P2,P3
P1,P2,P3
Signal
Rise time Am79R251 LD pin
Fall time Am79R251 LD pin
LD minimum pulse width
P1–3 data Setup time
P1–3 data hold time
Max P1–3 data delay
Am79R251
–
3 pins
Parameter
–
3 returns to 0 V state, thus protecting the
Min
4.5
4.5
3
Typ
Max
2
2
5
Unit
s