C8051F339-GM Silicon Laboratories Inc, C8051F339-GM Datasheet - Page 56

• Manufacturer Part Number: C8051F339-GM
• Description: IC MCU 16K FLASH 24QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F339-GM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 21
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 24-QFN
• Processor Series: C8051F3x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: I2C, SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 4
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: KSK-SL-TOOLSTICK, PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F336DK
• Minimum Operating Temperature: - 40 C
• Package: 24QFN EP
• Device Core: 8051
• Family Name: C8051F33x
• Maximum Speed: 25 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1426-5

C8051F336/7/8/9
10. Voltage Reference (C8051F336/8 only)
The Voltage reference multiplexer for the ADC is configurable to use an externally connected voltage refer-
ence, the on-chip reference voltage generator routed to the VREF pin, or the V
(see Figure 10.1). The REFSL bit in the Reference Control register (REF0CN, SFR Definition 10.1) selects
the reference source for the ADC. For an external source or the on-chip reference, REFSL should be set to
‘0’ to select the VREF pin. To use V
The BIASE bit enables the internal voltage bias generator, which is used by many of the analog peripherals
on the device. This bias is automatically enabled when any peripheral which requires it is enabled, and it
does not need to be enabled manually. The bias generator may be enabled manually by writing a ‘1’ to the
BIASE bit in register REF0CN. The electrical specifications for the voltage reference circuit are given in
Section “6. Electrical Characteristics” on page
The on-chip voltage reference circuit consists of a 1.2 V, temperature stable bandgap voltage reference
generator and a gain-of-two output buffer amplifier. The on-chip voltage reference can be driven on the
VREF pin by setting the REFBE bit in register REF0CN to a ‘1’. The maximum load seen by the VREF pin
must be less than 200 µA to GND. Bypass capacitors of 0.1 µF and 4.7 µF are recommended from the
VREF pin to GND. If the on-chip reference is not used, the REFBE bit should be cleared to ‘0’.
Important Note about the VREF Pin: When using either an external voltage reference or the on-chip ref-
erence circuitry, the VREF pin should be configured as an analog pin and skipped by the Digital Crossbar.
Refer to
of how to configure the pin in analog mode and to be skipped by the crossbar.
56
Section “20. Port Input/Output” on page 119
VDD
GND
Figure 10.1. Voltage Reference Functional Block Diagram
Recommended Bypass
4.7μF
R1
Capacitors
+
Reference
External
Voltage
Circuit
0.1μF
VREF
DD
as the reference source, REFSL should be set to ‘1’.
VDD
REF0CN
Rev.1.0
27.
0
1
IOSCE
for the location of the VREF pin, as well as details
N
Reference
REFBE
Internal
EN
EN
EN
Bias Generator
Temp Sensor
DD
To Analog Mux
(to ADC)
VREF
To ADC, IDAC,
Internal Oscillators
power supply voltage