MCP4725A3T-E/CH Microchip Technology, MCP4725A3T-E/CH Datasheet - Page 38

• Manufacturer Part Number: MCP4725A3T-E/CH
• Description: DAC 1-CH Resistor-String 12-Bit 6-Pin SOT-23 T/R
• Manufacturer: Microchip Technology

Specifications of MCP4725A3T-E/CH

• Package: 6SOT-23
• Resolution: 12 Bit
• Architecture: Resistor-String
• Digital Interface Type: Serial (2-Wire, I2C)
• Number Of Outputs Per Chip: 1
• Output Type: Voltage
• Full Scale Error: ±2 %FSR
• Integral Nonlinearity Error: ±14.5 LSB
• Maximum Settling Time: 6(Typ) us
• Settling Time: 6µs
• Number Of Bits: 12
• Data Interface: I²C, Serial
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP4725DM-PTPLS - BOARD DAUGHTER PICTAIL MCP4725
• Power Dissipation (max): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MCP4725A3T-E/CH; MCP4725A3T-E/CHTR

MCP4725
8.5.4.1
Some applications desires an output step magnitude of
1 mV with an output range of ±2.05V. The following
steps explain the design solution:
1.
2.
3.
:
4.
DS22039D-page 38
If R
If R
Calculate the range: +2.05V – (-2.05V) = 4.1V.
Calculate the resolution needed:
4.1V/1 mV = 4100 steps
Note that 2
The amplifier gain (R
must be equal to the desired minimum output to
achieve bipolar operation. Since any gain can
be realized by choosing resistor values (R
the V
4.1V is used, solve for the amplifier’s gain by
setting the DAC code to 0, knowing that the out-
put needs to be -2.05V. The equation can be
simplified to
Next, solve for R
4096, knowing that the output needs to be
+2.05V.
1
4
= 20 kΩ and R
= 20 kΩ, then R
----------------------- -
(
R
DD
3
–
-------- -
R
+
R
value must be selected first. If a V
R
Design a Bipolar DAC using
Example 8-3
4
1
R
2
12
4
=
)
–
------------ -
= 4096 for 12-bit resolution.
V
=
2.05
DD
2
3
2.05V
------------------------------------------------ -
3
= 10 kΩ, the gain will be 0.5.
and R
= 10 kΩ
=
2
–
------------ -
1.5 V
/R
+
2.05
4.1
4
1
(
⋅
by setting the DAC to
0.5 V
), multiplied by V
→
DD
⋅
R
----- -
R
DD
2
1
=
)
1
-- -
2
=
2
-- -
3
1
+R
DD
DD
2
of
),
,
© 2009 Microchip Technology Inc.