C8051F537-IT Silicon Laboratories Inc, C8051F537-IT Datasheet - Page 72

• Manufacturer Part Number: C8051F537-IT
• Description: IC 8051 MCU 2K FLASH 20TSSOP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F53xr

Specifications of C8051F537-IT

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (2K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: 336-1401

C8051F52x/F52xA/F53x/F53xA
5. Voltage Reference
The Voltage reference MUX on C8051F52x/F52xA/F53x/F53xA devices is configurable to use an exter-
nally connected voltage reference, the internal reference voltage generator, or the V
age (see Figure 5.1). The REFSL bit in the Reference Control register (REF0CN) selects the reference
source. For an external source or the internal reference applied to the V
To use V
The BIASE bit enables the internal voltage bias generator, which is used by the ADC, Temperature Sensor,
and internal oscillators. This bit is forced to logic 1 when any of the aforementioned peripherals are
enabled. The bias generator may be enabled manually by writing a 1 to the BIASE bit in register REF0CN;
see SFR Definition 5.1 for REF0CN register details. The electrical specifications for the voltage reference
circuit are given in Table 2.4 on page 30.
The internal voltage reference circuit consists of a temperature stable bandgap voltage reference genera-
tor and a gain-of-two output buffer amplifier. The output voltage is selectable between 1.5 V and 2.2 V. The
internal voltage reference can be driven out on the V
to a 1 (see Figure 5.1). The load seen by the V
the internal voltage reference, bypass capacitors of 0.1 µF and 4.7 µF are recommended from the V
pin to GND. If the internal reference is not used, the REFBE bit should be cleared to 0. Electrical specifica-
tions for the internal voltage reference are given in Table 2.4 on page 30.
72
DD
GND
VDD
as the reference source, REFSL should be set to 1.
R1
Reference
External
Voltage
Figure 5.1. Voltage Reference Functional Block Diagram
Circuit
VREF
VDD
REF0CN
REF
Rev. 1.3
0
1
pin must draw less than 200 µA to GND. When using
REF
IOSCEN
pin by setting the REFBE bit in register REF0CN
Reference
REFBE
Internal
REFLV
EN
EN
EN
Bias Generator
Temp Sensor
REF
pin, REFSL should be set to 0.
DD
To Analog Mux
(to ADC)
VREF
To ADC,
Internal Oscillators
power supply volt-
REF