AS1507
Data Sheet - Detailed Description
EEPROM (Non-Volatile Register)
There is an internal EEPROM register implemented to retain the wiper position after power down. During an ongoing
write cycle of the non-volatile register (tBUSY time) the system must not be powered down. A write cycle on the
EEPROM is indicated by the READY signal.
Data retention defines the ability of an EEPROM to retain data over time. The qualification has been done according to
JEDEC Retention Lifetime Specification (A117). The EEPROM is cycled to the specified endurance limit before the
data retention test is done. Based on activation energy of 0.6eV the data retention time derates over temperature as
shown in Figure 19 on page 8.
For the non-volatile register 1M endurance cycles and a data retention of 150 years are typical at 85 ºC. The non-vola-
tile register is factory trimmed to mid-scale.
Power-Up
The AS1507 contains an integrated power-up circuit. At power up, the data are transferred from the non-volatile mem-
ory to the wiper register. The wiper register moves to the stored position. This data transfer takes 5µs after the supply
has reached the POR trigger level.
Programming the Device
Write commands (see Table 6) require 16 clock cycles (see Figure 22 on page 12) to clock in the command and data.
Copy and Read commands (see Table 6) can use 8 clock cycles to clock in the command (see Figure 21 on page 12)
or 16 clock cycles. At 16 clock cycle commands the 8 data bits (D7:D0) are insignificant.
Table 6. Command/Data Word Format
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
Command
C7 C6 C5 C4 C3 C2 C1 C0 D7 D6 D5 D4 D3 D2 D1 D0
Write Wiper Register A
Write Wiper Register B
Write both Wiper Registers
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
1
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
Write to Non-Volatile
Register A
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
1
0
1
1
0
1
1
0
1
1
0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
Write to Non-Volatile
Register B
Write to both Non-Volatile
Registers
Copy Wiper Register A to Non-
Volatile Register
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Copy Wiper Register B to Non-
Volatile Register
Copy Both Wiper Registers to
Non-Volatile Registers
Copy Non-Volatile Register A
to Wiper Register
Copy Non-Volatile Register B
to Wiper Register
Copy Both Non-Volatile
Registers
to Wiper Registers
0
0
1
1
0
0
1
1
-
-
-
-
-
-
-
-
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