PIC16F721T-I/ML Microchip Technology, PIC16F721T-I/ML Datasheet - Page 89

• Manufacturer Part Number: PIC16F721T-I/ML
• Description: 7 KB FLASH, 256 B SRAM, 18 I/O 20 QFN 4x4mm T/R
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F721T-I/ML

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 7KB (4K x 14)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

11.0
This family of devices is equipped with a temperature
circuit designed to measure the operating temperature
of the silicon die. The circuit’s range of operating
temperature falls between -40°C and +85°C. The
output is a voltage that is proportional to the device
temperature. The output of the temperature indicator is
internally connected to the device ADC.
The circuit may be used as a temperature threshold
detector or a more accurate temperature indicator,
depending on the level of calibration performed. A one-
point calibration allows the circuit to indicate a
temperature closely surrounding that point. A two-point
calibration allows the circuit to sense the entire range
of temperature more accurately. Reference Application
Note AN1333, “Use and Calibration of the Internal
Temperature Indicator” (DS01333) for more details
regarding the calibration process.
11.1
Figure 11-1
temperature circuit. The proportional voltage output is
achieved by measuring the forward voltage drop across
multiple silicon junctions.
Equation 11-1
the temperature indicator.
EQUATION 11-1:
The temperature sense circuit is integrated with the
Fixed
Section 10.0 “Fixed Voltage Reference”
information.
The circuit is enabled by setting the TSEN bit of the
FVRCON register. When disabled, the circuit draws no
current.
The circuit operates in either high or low range. The high
range, selected by setting the TSRNG bit of the
FVRCON register, provides a wider output voltage. This
provides more resolution over the temperature range,
but may be less consistent from part to part. This range
requires a higher bias voltage to operate and thus, a
higher V
The low range is selected by clearing the TSRNG bit of
the FVRCON register. The low range generates a lower
voltage drop and thus, a lower bias voltage is needed to
operate the circuit. The low range is provided for low
voltage operation.
 2010 Microchip Technology Inc.
Voltage
DD
High Range: V
Low Range: V
TEMPERATURE INDICATOR
MODULE
Circuit Operation
is needed.
shows a simplified block diagram of the
describes the output characteristics of
Reference
OUT
V
OUT
OUT
= V
= V
RANGES
DD
DD
(FVR)
- 2V
- 4V
T
T
module.
for more
See
FIGURE 11-1:
11.2
When the temperature circuit is operated in low range,
the device may be operated at any operating voltage
that is within specifications.
When the temperature circuit is operated in high range,
the device operating voltage, V
enough to ensure that the temperature circuit is
correctly biased.
Table 11-1
range setting.
TABLE 11-1:
11.3
The output of the circuit is measured using the internal
Analog-to-Digital converter. Channel 14 is reserved for
the temperature circuit output. Refer to
“Analog-to-Digital Converter (ADC) Module”
detailed information.
Note:
Min. V
PIC16F/LF720/721
Minimum Operating V
Minimum Sensing Temperature
DD
Temperature Output
shows the recommended minimum V
3.6V
, TSRNG = 1
Every time the ADC MUX is changed to
the temperature indicator output selection
(CHS bit in the ADCCON0 register), wait
500 usec for the sampling capacitor to
fully charge before sampling the tempera-
ture indicator output.
V
DD
RECOMMENDED V
RANGE
TEMPERATURE CIRCUIT
DIAGRAM
V
OUT
(ADCON0 register)
TSEN
TSRNG
CHS bits
Min. V
ADC
MUX
n
DD
DD
DS41430A-page 89
, must be high
DD
1.8V
, TSRNG = 0
DD
vs.
ADC
Section 9.0
VS.
DD
vs.
for