MAX5478ETE-T Maxim Integrated Products, MAX5478ETE-T Datasheet - Page 11

• Manufacturer Part Number: MAX5478ETE-T
• Description: Digital Potentiometer ICs
• Manufacturer: Maxim Integrated Products

Specifications of MAX5478ETE-T

• Number Of Pots: Dual
• Taps Per Pot: 256
• Resistance: 50 KOhms
• Wiper Memory: Non Volatile
• Digital Interface: Serial (2-Wire, I2C)
• Operating Supply Voltage: 5 V
• Supply Current: 15 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.25 V
• Supply Voltage (min): 2.7 V
• Package / Case: TQFN EP-16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX5477/MAX5478/MAX5479 feature an internal,
nonvolatile EEPROM that stores the wiper state for ini-
tialization during power-up. The shift register decodes
the command and address bytes, routing the data to
the proper memory registers. Data written to a volatile
memory register immediately updates the wiper posi-
tion, or writes data to a nonvolatile register for storage
(see
The volatile register retains data as long as the device
is powered. Removing power clears the volatile regis-
ter. The nonvolatile register retains data even after
power is removed. Upon power-up, the power-on reset
circuitry controls the transfer of data from the non-
volatile register to the volatile register.
Table 2. Write-Protect Behavior of VREG and NVREG
Table 3. Command Byte Summary
NVREGxVREG
VREGxNVREG
NVREGxVREG
VREGxNVREG
NVREGxVREG
VREGxNVREG
Write to VREG
Write to NVREG
Copy NVREG to VREG
Copy VREG to NVREG
SCL CYCLE
NUMBER
NVREG
NVREG
NVREG
VREG
VREG
VREG
Table
COMMAND
3).
START
(S)
Dual, 256-Tap, Nonvolatile, I
______________________________________________________________________________________
A6 A5 A4 A3 A2 A1 A0
1
0
0
0
0
0
0
0
0
0
0
0
0
2
1
1
1
1
1
1
1
1
1
1
1
1
I
Wiper position updates with I
No change to NVREG.
No change to VREG or wiper position.
I
Copy NVREG to VREG.
Wiper position updates with NVREG data.
No change to NVREG.
Copy VREG to NVREG.
No change to VREG or wiper position.
ADDRESS BYTE
2
2
C data is written to VREG.
C data is written to NVREG.
3
0
0
0
0
0
0
0
0
0
0
0
0
4
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
1 A2 A1 A0 0
5
6
Digital Interface
7
WP = 0
8
ACK
(A)
9
10 11 12 13 14 15 16 17 18
0
0
0
0
0
0
0
0
0
0
0
0
2
C data.
TX NV V R3 R2 R1 R0
0
0
1
1
0
0
1
1
0
0
1
1
COMMAND BYTE
0
1
1
0
0
1
1
0
0
1
1
0
1
0
0
1
1
0
0
1
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
A write-protect feature prevents accidental overwriting of
the EEPROM. Connect WP to V
to prevent any EEPROM write cycles. Writing to the
volatile register (VREG) while WP = 1 updates the wiper
position with the protected data stored in the nonvolatile
register (NVREG). Connect WP to GND to allow write
commands to the EEPROM and to update the wiper
position from either the value in the EEPROM or directly
from the I
increases the supply current by 19.6µA (max).
To ensure a fail-safe, write-protect feature, write the
data to be protected to both the nonvolatile and volatile
registers before pulling WP high. Releasing WP (WP =
0) and sending partial or invalid I
as single-byte address polling) can load the volatile
Digital Potentiometers
0
0
0
0
0
0
0
0
0
0
0
0
Copy NVREG to VREG.
Wiper position updates with NVREG data.
No change to NVREG.
No change to VREG or wiper position.
No change to NVREG.
Copy NVREG to VREG.
Wiper position updates with NVREG data.
No change to NVREG.
No change to VREG or wiper position.
No change to NVREG.
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
2
ACK
C interface
(A)
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
19 20 21 22 23 24 25 26
DATA BYTE
(Table
2
WP = 1
C-Interface,
2). Connecting WP to GND
DD
Write Protect (WP)
or leave unconnected
2
C commands (such
ACK
(A)
27
STOP
(P)
WIPER A
WIPER B
A AND B
WIPERS
NOTES
ONLY
ONLY
11