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參數(shù)資料
| 型號： | ADUC841 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU |
| 中文描述： | MicroConverter的12位ADC和嵌入式高速DAC的62 - kB的閃存微控制器 |
| 文件頁數(shù)： | 28/88頁 |
| 文件大?。?/td> | 903K |
| 代理商： | ADUC841 |
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ADuC841/ADuC842/ADuC843
Table 11. Some Single-Supply Op Amps
Op Amp Model
OP281/OP481
OP191/OP291/OP491
OP196/OP296/OP496
OP183/OP283
OP162/OP262/OP462
AD820/AD822/AD824
AD823
Rev. 0 | Page 28 of 88
Characteristics
Micropower
I/O Good up to V
DD
, Low Cost
I/O to V
DD
, Micropower, Low Cost
High Gain-Bandwidth Product
High GBP, Micro Package
FET Input, Low Cost
FET Input, High GBP
Keep in mind that the ADC’s transfer function is 0 V to V
REF
,
and that any signal range lost to amplifier saturation near
ground will impact dynamic range. Though the op amps in
Table 11 are capable of delivering output signals that very
closely approach ground, no amplifier can deliver signals all the
way to ground when powered by a single supply. Therefore, if a
negative supply is available, you might consider using it to
power the front end amplifiers. If you do, however, be sure to
include the Schottky diodes shown in Figure 31 (or at least the
lower of the two diodes) to protect the analog input from
undervoltage conditions. To summarize this section, use the
circuit in Figure 31 to drive the analog input pins of the parts.
Voltage Reference Connections
The on-chip 2.5 V band gap voltage reference can be used as the
reference source for the ADC and DACs. To ensure the accuracy
of the voltage reference, you must decouple the C
REF
pin to
ground with a 0.47 μF capacitor, as shown in Figure 32. Note
that this is different from the ADuC812/ADuC831/ADuC832.
BUFFER
BUFFER
0.47
μ
F
51
V
REF
= NC
C
REF
2.5V
BAND GAP
REFERENCE
ADuC841/ADuC842/ADuC843
0
Figure 32. Decoupling V
REF
and C
REF
If the internal voltage reference is to be used as a reference for
external circuitry, the C
REF
output should be used. However, a
buffer must be used in this case to ensure that no current is
drawn from the C
REF
pin itself. The voltage on the C
REF
pin is that
of an internal node within the buffer block, and its voltage is
critical for ADC and DAC accuracy. The parts power up with
their internal voltage reference in the off state.
If an external voltage reference is preferred, it should be
connected to the C
REF
pin as shown in Figure 33. Bit 6 of the
ADCCON1 SFR must be set to 1 to switch in the external
reference voltage.
To ensure accurate ADC operation, the voltage applied to C
REF
must be between 1 V and AV
DD
. In situations where analog
input signals are proportional to the power supply (such as in
some strain gage applications), it may be desirable to connect
the C
REF
pin directly to AV
DD
. Operation of the ADC or DACs
with a reference voltage below 1 V, however, may incur loss of
accuracy, eventually resulting in missing codes or non-
monotonicity. For that reason, do not use a reference voltage
lower than 1 V.
BUFFER
51
C
REF
EXTERNAL
VOLTAGE
REFERENCE
1 = EXTERNAL
0 = INTERNAL
0.1
μ
F
2.5V
BAND GAP
REFERENCE
ADuC841/ADuC842/ADuC843
ADCCON1.6
V
DD
0
V
REF
= NC
Figure 33. Using an External Voltage Reference
Configuring the ADC
The parts’ successive approximation ADC is driven by a divided
down version of the master clock. To ensure adequate ADC
operation, this ADC clock must be between 400 kHz and
8.38 MHz. Frequencies within this range can be achieved easily
with master clock frequencies from 400 kHz to well above
16 MHz, with the four ADC clock divide ratios to choose from.
For example, set the ADC clock divide ratio to 8 (i.e., ADCCLK
= 16.777216 MHz/8 = 2 MHz) by setting the appropriate bits in
ADCCON1 (ADCCON1.5 = 1, ADCCON1.4 = 0). The total
ADC conversion time is 15 ADC clocks, plus 1 ADC clock for
synchronization, plus the selected acquisition time (1, 2, 3, or 4
ADC clocks). For the preceding example, with a 3-clock
acquisition time, total conversion time is 19 ADC clocks (or
9.05 μs for a 2 MHz ADC clock).
In continuous conversion mode, a new conversion begins each
time the previous one finishes. The sample rate is then simply
the inverse of the total conversion time described previously. In
the preceding example, the continuous conversion mode sample
rate is 110.3 kHz.
相關PDF資料 |
PDF描述 |
|---|---|
| ADUC841BCP62-3 | MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU |
| ADUC841BCP62-5 | Cable Gland (Clamp); Connector Shell Size:10SL, 12S; Thread Size:5/8-24; Approval Categories:MIL-C-5015; Series:97 RoHS Compliant: Yes |
| ADUC841BCP8-3 | 10-823955-004 |
| ADUC841BCP8-5 | Cable Gland (Clamp); Connector Shell Size:14, 14S; Thread Size:3/4-20; Body Material:Zinc Alloy |
| ADUC841BS62-3 | MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ADUC841BCP32-5 | 制造商:Analog Devices 功能描述:MICROCONVERTER 1-CYCLE VERSION ADUC829 - Trays |
| ADUC841BCP62-3 | 制造商:Analog Devices 功能描述:MCU 8-Bit ADuC8xx 8052 CISC 62KB Flash 3V 56-Pin LFCSP EP 制造商:Rochester Electronics LLC 功能描述:8BIT CISC 62KB FLASH 20MHZ 3.3V 56LFCSP - Bulk |
| ADUC841BCP62-5 | 制造商:Analog Devices 功能描述:MCU 8-Bit ADuC8xx 8052 CISC 62KB Flash 5V 56-Pin LFCSP EP |
| ADUC841BCP8-3 | 制造商:Analog Devices 功能描述:MCU 8-bit ADuC8xx 8052 CISC 62KB Flash 3V 56-Pin LFCSP EP 制造商:Rochester Electronics LLC 功能描述:8BIT CISC 62KB FLASH 20MHZ 3.3V 56LFCSP - Bulk |
| ADUC841BCP8-5 | 制造商:AD 制造商全稱:Analog Devices 功能描述:MicroConverter 12-Bit ADCs and DACs with Embedded High Speed 62-kB Flash MCU |
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