MCP3901A0-I/SS Microchip Technology, MCP3901A0-I/SS Datasheet - Page 29

• Manufacturer Part Number: MCP3901A0-I/SS
• Description: IC AFE 24BIT 64KSPS 20-SSOP
• Manufacturer: Microchip Technology

Specifications of MCP3901A0-I/SS

• Number Of Bits: 24
• Number Of Channels: 2
• Power (watts): 10mW
• Voltage - Supply, Analog: 4.5 V ~ 5.5 V
• Voltage - Supply, Digital: 2.7 V ~ 5.5 V
• Package / Case: 20-SSOP
• Ic Function: Analog Front End Device IC
• Supply Voltage Range: 4.5V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Supply Voltage Max: 5.5V
• Output Voltage: 0.4 V
• Output Power: 14 mW
• Input Voltage: 4.5 V to 5.5 V, 2.7 V to 5.5 V
• Switching Frequency: 4 MHz
• Mounting Style: SMD/SMT
• Number Of Outputs: 2
• No. Of Channels: 2
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: MCP3901AO-I/SS; MCP3901AO-I/SS

TABLE 5-6:
TABLE 5-7:
5.7
5.7.1
The MCP3901 contains an internal voltage reference
source specially designed to minimize drift over
temperature. In order to enable the internal voltage
reference, the VREFEXT bit in the configuration
register must be set to 0 (default mode). This internal
V
typical value of this voltage reference is 2.37V ±2%.
The internal reference has a very low typical
temperature coefficient of ±12 ppm/°C, allowing the
output codes to have minimal variation with respect to
temperature since they are proportional to (1/V
The noise of the internal voltage reference is low
enough not to significantly degrade the SNR of the
ADC if compared to a precision external low-noise
voltage reference.
The output pin for the internal voltage reference is
REFIN+/OUT.
When the internal voltage reference is enabled,
REFIN- pin should always be connected to AGND.
For optimal ADC accuracy, appropriate bypass
capacitors should be placed between REFIN+/OUT
and AGND. De-coupling at the sampling frequency,
around 1 MHz, is important for any noise around this
frequency will be aliased back into the conversion data.
0.1 µF ceramic and 10 µF tantalum capacitors are
recommended.
© 2009 Microchip Technology Inc.
0 1 1 1
0 1 1 1
0 0 0 0
1 1 1 1
1 0 0 0
1 0 0 0
0 1 1 1
0 1 1 1
0 0 0 0
1 1 1 1
1 0 0 0
1 0 0 0
REF
supplies reference voltage to both channels. The
Voltage Reference
INTERNAL VOLTAGE REFERENCE
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
OSR = 64 OUTPUT CODE EXAMPLES
OSR = 32 OUTPUT CODE EXAMPLES
ADC Output code (MSB First)
ADC Output code (MSB First)
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
1 1 1 1
1 1 1 1
0 0 0 0
1 1 1 1
0 0 0 0
0 0 0 0
REF
).
1 1 1 1
1 1 1 0
0 0 0 0
1 1 1 1
0 0 0 1
0 0 0 0
1 0 0 0
0 0 0 0
0 0 0 0
1 0 0 0
1 0 0 0
0 0 0 0
These bypass capacitors are not mandatory for correct
ADC operation, but removing these capacitors may
degrade accuracy of the ADC. The bypass capacitors
also help for applications where the voltage reference
output is connected to other circuits. In this case,
additional buffering may be needed as the output drive
capability of this output is low.
5.7.2
When the VREFEXT bit is high, the two reference pins
(REFIN+/OUT, REFIN-) become a differential voltage
reference input. The voltage at the REFIN+/OUT is
noted V
V
the following equation:
EQUATION 5-4:
The specified V
REFIN- pin voltage (V
Typically, for single-ended reference applications, the
REFIN- pin should be directly connected to AGND.
REF
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
-. The differential voltage input value is given by
REF
+ and the voltage at the REFIN- pin is noted
DIFFERENTIAL EXTERNAL
VOLTAGE INPUTS
Hexadecimal
Hexadecimal
0x7FFFE0
0xFFFFF0
0x7FFFF0
0x800010
0x800000
REF
0x000000
0x7FFF80
0x7FFF00
0xFFFF80
0x800080
0x800000
V
0x000000
REF
range is from 2.2V to 2.6V. The
=V
REF
REF
-) should be limited to ±0.3V.
+ - V
MCP3901
REF
20-bit resolution
17-bit resolution
DS22192B-page 29
-
+ 524, 287
+ 524, 286
- 524, 288
- 524,287
+ 65, 535
+ 65, 534
Decimal
- 65, 536
Decimal
- 65,535
-1
-1
0
0