MAX5478EUD+ Maxim Integrated Products, MAX5478EUD+ Datasheet - Page 11
![IC POT DGTL DUAL 256-TAP 14TSSOP](/photos/6/57/65725/406-14-tssop_sml.jpg)
MAX5478EUD+
Manufacturer Part Number
MAX5478EUD+
Description
IC POT DGTL DUAL 256-TAP 14TSSOP
Manufacturer
Maxim Integrated Products
Datasheet
1.MAX5477ETE.pdf
(17 pages)
Specifications of MAX5478EUD+
Taps
256
Resistance (ohms)
50K
Number Of Circuits
2
Temperature Coefficient
35 ppm/°C Typical
Memory Type
Non-Volatile
Interface
I²C, 2-Wire Serial
Voltage - Supply
2.7 V ~ 5.25 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
14-TSSOP
Resistance In Ohms
50K
Number Of Pots
Dual
Taps Per Pot
256
Resistance
325 Ohms
Wiper Memory
Non Volatile
Digital Interface
Serial (2-Wire)
Operating Supply Voltage
2.7 V to 5.25 V
Supply Current
1 uA
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Description/function
Dual, 256 Tap, Nonvolatile, I2C, 50k Digital Potentiometer
Mounting Style
SMD/SMT
Supply Voltage (max)
5.25 V
Supply Voltage (min)
2.7 V
Tolerance
25 %
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