- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄361412 > TC850IJL (Microchip Technology Inc.) CAP 0.33UF 25V 20% Z5U SMD-1206 TR-7 PLATED-NI/SN PDF資料下載
參數(shù)資料
| 型號： | TC850IJL |
| 廠商： | Microchip Technology Inc. |
| 英文描述： | CAP 0.33UF 25V 20% Z5U SMD-1206 TR-7 PLATED-NI/SN |
| 中文描述： | 15位，快速集成的CMOS A / D轉換 |
| 文件頁數(shù)： | 11/14頁 |
| 文件大?。?/td> | 164K |
| 代理商： | TC850IJL |
3-87
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
where f
CLOCK
is the crystal or external oscillator frequency
and V
FS
is the maximum input voltage.
The integration capacitor should be selected for low
dielectric absorption to prevent roll-over errors. A polypro-
pylene, polyester or polycarbonate dielectric capacitor is
recommended.
Reference Capacitors
The reference capacitors require a low leakage dielec-
tric, such as polypropylene, polyester or polycarbonate. A
value of 1
μ
F is recommended for operation over the tem-
perature range. If high-temperature operation is not re-
quired, the C
REF
values can be reduced.
Auto-Zero Capacitors
Five capacitors are required to auto-zero the input
buffer, integrator amplifier, and comparator. Recommended
capacitors are 0.1
μ
F film dielectric (such as polyester or
polypropylene). Ceramic capacitors are not recommended.
DIGITAL SECTION APPLICATION
Oscillator
The TC850 may operate with a crystal oscillator. The
crystal selected should be designed for a Pierce oscillator,
such as an AT-cut quartz crystal. The crystal oscillator
schematic is shown in Figure 6.
Since low frequency crystals are very large and ceramic
resonators are too lossy, the TC850 clock should be derived
from an external source, such as a microprocessor clock.
The clock should be input on the OSC
1
pin and no connec-
tion should be made to the OSC
2
pin. The external clock
should swing between DGND and V
DD
.
Since oscillator frequency is
÷
4 internally and each
conversion requires 1280 internal clock cycles, the conver-
sion time will be:
Conversion time = f
CLOCK
×
4
×
1280.
Integration Capacitor
The integration capacitor should be selected to produce
an integrator swing of
≈
4V at full scale. The capacitor value
is easily calculated:
An important advantage of the integrating ADC is the
ability to reject periodic noise. This feature is most often
used to reject line frequency (50Hz or 60Hz) noise. Noise
rejection is accomplished by selecting the integration period
equal to one or more line frequency cycles. The desired
clock frequency is selected as follows:
Data Bus Interfacing
The TC850 provides an easy and flexible digital inter-
face. A 3-state data bus and six control inputs permit the
TC850 to be treated as a memory device, in most applica-
tions. The conversion result can be accessed over an 8-bit
bus or via a
μ
P I/O port.
A typical
μ
P bus interface for the TC850 is shown in
Figure 7. In this example, the TC850 operates in the demand
mode, and conversion begins when a write operation is
performed to any decoded address space. The BUSY
output interrupts the
μ
P at the end-of-conversion.
The A/D conversion result is read as three memory
bytes. The two LSBs of the address bus select high/low byte
and overrange/polarity bit data, while high-order address
lines enable the CE input.
Figure 8 shows a typical interface to a
μ
P I/O port or
single-chip
μ
C. The TC850 operates in the continuous
mode, and can either interrupt the
μ
C/
μ
P or be polled with an
input pin.
f
CLOCK
= f
NOISE
×
4
×
256,
where f
NOISE
is the noise frequency to be rejected, 4 repre-
sents the clock divider, and 256 is the number of integrate
cycles.
For example, 60Hz noise will be rejected with a clock
frequency of 61.44kHz, giving a conversion rate of 12
conversions/sec. Integer submultiples of 61.44kHz (such as
30.72kHz, etc.) will also reject 60Hz noise. For 50Hz noise
rejection, a 51.2kHz frequency is recommended.
If noise rejection is not important, other clock frequen-
cies can be used. The TC850 will typically operate at
conversion rates ranging from 3 to 40 conversions/sec,
corresponding to oscillator frequencies from 15.36kHz to
204.8kHz.
Figure 6. Crystal Oscillator Schematic
C =
V
FS
R
INT
4 ,
4V f
CLOCK
100 pF
100 pF
17
TC850
18
61.44 kHz
10 M
SYSTEM
CLOCK
÷
4
TC850
15-BIT, FAST-INTEGRATING CMOS
ANALOG-TO-DIGITAL CONVERTER
相關PDF資料 |
PDF描述 |
|---|---|
| TC850ILW | 15-Bit, Fast Integrating CMOS A/D Converter |
| TC850 | 15-Bit, Fast Integrating CMOS A/D Converter |
| TC850CLW | 15-Bit, Fast Integrating CMOS A/D Converter |
| TC850CPL | 15-Bit, Fast Integrating CMOS A/D Converter |
| TC850ILW | 15-BIT, FAST-INTEGRATING CMOS ANALOG-TO-DIGITAL CONVERTER |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| TC850ILW | 功能描述:模數(shù)轉換器 - ADC 16 Bit Hi Speed A/D RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| TC850ILW713 | 功能描述:模數(shù)轉換器 - ADC 16 Bit Hi Speed A/D RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| TC8521AM | 制造商:TOSHIBA 制造商全稱:Toshiba Semiconductor 功能描述:REAL TIME CLOCK ケ |
| TC8521AP | 制造商:TOSHIBA 制造商全稱:Toshiba Semiconductor 功能描述:REAL TIME CLOCK ケ |
| TC8566AF | 制造商:TOSHIBA 制造商全稱:Toshiba Semiconductor 功能描述:FLOPPY DISK CONTROLLER |
發(fā)布緊急采購，3分鐘左右您將得到回復。