C8051F131R Silicon Labs, C8051F131R Datasheet - Page 115

• Manufacturer Part Number: C8051F131R
• Description: 8-bit Microcontrollers - MCU 128kB 100MIPS 8448B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F131R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 100 MHz
• Program Memory Size: 128 KB
• Data Ram Size: 8.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 9
• Data Rom Size: 64 KB
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V

9.2.
On the C8051F121/3/5/7 devices, the REF0CN register also allows selection of the voltage reference
source for ADC0 and ADC2, as shown in SFR Definition 9.2. Bits AD0VRS and AD2VRS in the REF0CN
register select the ADC0 and ADC2 voltage reference sources, respectively. The VREFA pin provides a
voltage reference input for ADC0 and ADC2, which can be connected to an external precision reference or
the internal voltage reference. ADC0 may also reference the DAC0 output internally, and ADC2 may refer-
ence the analog power supply voltage, via the VREF multiplexers shown in Figure 9.2.
Figure 9.2. Voltage Reference Functional Block Diagram (C8051F121/3/5/7)
Reference Configuration on the C8051F121/3/5/7
Reference
External
Voltage
Circuit
DGND
VDD
Recommended Bypass
4.7F
R1
Capacitors
+
0.1F
VREFA
VREF
Rev. 1.4
REF0CN
C8051F120/1/2/3/4/5/6/7
DAC0
DAC1
Ref
REFBE
x2
AV+
1
0
0
1
C8051F130/1/2/3
Band-Gap
BIASE
1.2V
EN
ADC2
ADC0
Ref
Ref
Bias to
ADCs,
DACs
115