AD5222BR10 Analog Devices Inc, AD5222BR10 Datasheet - Page 9

• Manufacturer Part Number: AD5222BR10
• Description: IC DGTL POT DUAL 128POS 14-SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD5222BR10

• Rohs Status: RoHS non-compliant
• Taps: 128
• Resistance (ohms): 10K
• Number Of Circuits: 2
• Temperature Coefficient: 35 ppm/°C Typical
• Memory Type: Volatile
• Interface: Up/Down Counter
• Voltage - Supply: 2.7 V ~ 5.5 V, ±2.3 V ~ 2.7 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Resistance In Ohms: 10K
• Number Of Elements: 2
• # Of Taps: 128
• Resistance (max): 10KOhm
• Power Supply Requirement: Single/Dual
• Interface Type: Increment-Decrement
• Single Supply Voltage (typ): 3/5V
• Dual Supply Voltage (typ): ±2.5V
• Single Supply Voltage (min): 2.7V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): ±2.3V
• Dual Supply Voltage (max): ±2.7V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 14
• Lead Free Status / Rohs Status: Not Compliant

PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation
The nominal resistance of the RDAC between Terminals A and
B are available with values of 10 k , 50 k , 100 k , and 1 M
The final three characters of the part number determine the
nominal resistance value, e.g., 10 k = 10; 50 k = 50; 100 k
= 100; 1 M
has 128 contact points accessed by the wiper terminal, plus the
B terminal contact. At power ON, the resistance from the wiper
to either end Terminal A or B is approximately equal. Pulsing
the CLK pin will increase the resistance from the wiper W to
Terminal B by one unit of R
resistance R
the clock pin. Each segment of the internal resistor string has a
nominal resistance value of R
in the case of the 10 k AD5222BR10 product. Care should be
taken to limit the current flow between W and B in the direct
contact state (R
avoid degradation or possible destruction of the internal switch
contact.
Like the mechanical potentiometer the RDAC replaces, it is
totally symmetrical (see Figure 3). The resistance between the
wiper W and Terminal A also produces a digitally controlled
resistance R
should be tied to the wiper.
The typical part-to-part distribution of R
dependent having a 30% variation. The change in R
temperature has a –35 ppm/ C temperature coefficient.
REV. 0
WB
WA
= 1M. The nominal resistance (R
. When these terminals are used the B-terminal
is determined by the number of pulses applied to
WB
code = 0) to a maximum value of 20 mA to
S
S
= R
resistance, see Figure 33. The
AB
/128, which becomes 78
BA
is process-lot-
AB
) of the VR
BA
with
–9–
The R
grammed near the B-terminal due to the larger percentage
contribution of the wiper contact switch resistance, which has a
0.5%/ C temperature coefficient. Figures 9 and 10 show the
effect of the wiper contact resistance as a function of code setting.
PROGRAMMING THE POTENTIOMETER DIVIDER
Voltage Output Operation
The digital potentiometer easily generates an output voltage
proportional to the input voltage applied to a given terminal.
For example connecting A-terminal to 5 V and B-terminal to
ground produces an output voltage at the wiper which can be
any value starting at zero volts up to 1 LSB less than 5 V. Each
LSB of voltage is equal to the voltage applied across Terminals
AB divided by the 128-position resolution of the potentiometer
divider. The general equation defining the output voltage with
respect to ground for any given input voltage applied to Termi-
nals AB is:
D represents the current contents of the internal up/down counter.
Operation of the digital potentiometer in the divider mode
results in more accurate operation over temperature. Here the
output voltage is dependent on the ratio of the internal resistors
not the absolute value, therefore, the drift improves to 20 ppm/ C.
V
W
BA
(D) = D/128
temperature coefficient increases as the wiper is pro-
V
AB
+ V
B
AD5222
(1)