DS1848B-050 Maxim Integrated Products, DS1848B-050 Datasheet - Page 6

• Manufacturer Part Number: DS1848B-050
• Description: Digital Potentiometer ICs
• Manufacturer: Maxim Integrated Products

Specifications of DS1848B-050

• Number Of Pots: Dual
• Taps Per Pot: 256
• Resistance: 10 KOhms, 50 KOhms
• Wiper Memory: Non Volatile
• Digital Interface: Serial (2-Wire)
• Operating Supply Voltage: 3.3 V, 5 V
• Supply Current: 1 mA
• Maximum Operating Temperature: + 95 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 3 V
• Package / Case: CSBGA-16
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PROGRAMMING THE LOOK-UP TABLE (LUT)
The following equation can be used to determine which resistor position setting, 00h – FFh, should be
written in the LUT to achieve a given resistance at a specific temperature.
DS1848-050
a = 3.78964 for the 50kW resistor
a = 19.74866 for the 10kW resistor
DS1848-010
a = 8.394533 for both 10kW resistors
R = resistance desired at the output terminal
C = temperature in degrees Celsius
u, v, w, x, y, and z are calibration constants programmed into each of the corresponding look-up tables.
Their addresses and LSB values are given in Table 1 below. Resistor 1 variables are found in Look-Up
table 1 of the EEPROM, and Resistor 2 variables are found in Look-Up Table 2. After these values are
read, they should be overwritten with the appropriate temperature specific resistance settings. Copies of
these values can also be found in the User EEPROM memory.
LOOK-UP VARIABLE ADDRESSES Table1
When shipped from the factory, all other memory locations in the LUTs are programmed to FFh (except
bytes 00h-07h of Table 1 and 2 which may be factory programmed to values other than FFh).
Note: Memory locations 44h – 47h, which cover the temperature range (+96ºC to +102ºC), are outside
of the specified operating temperature range (-40ºC to +95ºC). However, the values stored in these
locations will act as valid resistance settings if the temperature exceeds +95ºC. Therefore, Dallas
Semiconductor recommends that the user program a resistance value into all LUT locations. Failure to do
so will result in the part being set to the default value.
pos
LUT (HEX)
Address in
(
a
2A – 2B
2C – 2D
2E – 2F
28 – 29
30 – 31
32 – 33
,
R
,
C
)
=
R
( )
-
x
u
·
·
Variable
[
1
[
1
+
+
w
u
v
x
y
z
y
v
·
·
(
C
(
C
-
-
25
25
10
LSB
10
10
10
)
2
2
)
+
-8
-8
-10
+
-6
-9
-7
z
w
·
·
(
C
(
C
-
-
25
25
)
2
)
]
2
]
-
a
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