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參數(shù)資料
| 型號(hào)： | AD7651ACP |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | ADC |
| 英文描述： | 16-Bit 100 kSPS PulSAR Unipolar ADC with Reference |
| 中文描述： | 1-CH 16-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL/PARALLEL ACCESS, QCC48 |
| 封裝： | MO-220-VKKD-2, LFCSP-48 |
| 文件頁數(shù)： | 18/28頁 |
| 文件大?。?/td> | 709K |
| 代理商： | AD7651ACP |
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AD7651
Voltage Reference Input
The AD7651 allows the choice of either a very low temperature
drift internal voltage reference or an external 2.5 V reference.
For applications that use multiple AD7651s, it is more effective
to use the internal buffer to buffer the reference voltage.
Unlike many ADCs with internal references, the internal
reference of the AD7651 provides excellent performance and
can be used in almost all applications.
Care should be taken with the voltage reference’s temperature
coefficient, which directly affects the full-scale accuracy if this
parameter matters. For instance, a ±15 ppm/°C temperature
coefficient of the reference changes full scale by ±1 LSB/°C.
To use the internal reference along with the internal buffer,
PDREF and PDBUF should both be LOW. This will produce a
1.207 V voltage on REFBUFIN which, amplified by the buffer,
will result in a 2.5 V reference on the REF pin.
Note that V
REF
can be increased to AVDD – 1.85 V. Since the
input range is defined in terms of V
REF
, this would essentially
increase the range to 0 V to 3 V with an AVDD above 4.85 V.
The
AD780
can be selected with a 3 V reference voltage.
The output impedance of REFBUFIN is 11 k
(minimum) when
the internal reference is enabled.
It is useful to decouple
REFBUFIN with a 100 nF ceramic capacitor. Thus, the 100 nF
capacitor provides an RC filter for noise reduction.
The TEMP pin, which measures the temperature of the AD7651,
can be used as shown in
applied to one of the inputs of the analog switch (e.g.,
ADG779
),
and the ADC itself is used to measure its own temperature. This
configuration is very useful for improving the calibration
accuracy over the temperature range.
. The output of TEMP pin is
Figure 24
Figure 24. Temperature Sensor Connection Diagram
To use an external reference along with the internal buffer,
PDREF should be HIGH and PDBUF should be LOW. This
powers down the internal reference and allows the 2.5 V
reference to be applied to REFBUFIN.
ADG779
AD8021
C
C
02964-0-024
ANALOG INPUT
(UNIPOLAR)
AD7651
IN
TEMPERATURE
SENSOR
TEMP
To use an external reference directly on REF pin, PDREF and
PDBUF should both be HIGH.
PDREF and PDBUF respectively power down the internal
reference and the internal reference buffer. Note that the PDREF
and PDBUF input current should never exceed 20 mA. This
could eventually occur when input voltage is above AVDD (for
instance at power up). In this case, a 100 series resistor is
recommended.
Power Supply
The AD7651 uses three power supply pins: an analog 5 V supply
AVDD, a digital 5 V core supply DVDD, and a digital input/
output interface supply OVDD. OVDD allows direct interface
with any logic between 2.7 V and DVDD + 0.3 V. To reduce the
supplies needed, the digital core (DVDD) can be supplied
through a simple RC filter from the analog supply, as shown in
. The AD7651 is independent of power supply
sequencing once OVDD does not exceed DVDD by more than
0.3 V, and is thus free of supply voltage induced latch-up.
The internal reference is temperature compensated to 2.5 V ±
20 mV. The reference is trimmed to provide a typical drift of 7
. This typical drift characteristic is shown in
For improved drift performance, an external reference such as
the
AD780
can be used.
.
ppm/°C
Figure 17
Figure 22
The AD7651 voltage reference input REF has a dynamic input
impedance; it should therefore be driven by a low impedance
source with efficient decoupling between the REF and REFGND
inputs. This decoupling depends on the choice of the voltage
reference but usually consists of a low ESR tantalum capacitor
connected to REF and REFGND with minimum parasitic
inductance. A 10 μF (X5R, 1206 size) ceramic chip capacitor (or
47 μF tantalum capacitor) is appropriate when using either the
internal reference or one of these recommended reference
voltages:
The low noise, low temperature drift
ADR421
and
AD780
The low power
ADR291
The low cost
AD1582
Rev. 0 | Page 18 of 28
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD7651AST | 16-Bit 100 kSPS PulSAR Unipolar ADC with Reference |
| AD7651ASTRL | 16-Bit 100 kSPS PulSAR Unipolar ADC with Reference |
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| AD7654ACP | Dual 2-Channel Simultaneous Sampling SAR 500 kSPS 16-Bit ADC |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD7651ACPRL | 制造商:Analog Devices 功能描述:ADC Single SAR 100ksps 16-bit Parallel/Serial 48-Pin LFCSP EP T/R |
| AD7651ACPZ | 功能描述:IC ADC 16BIT UNIPOLAR 48LFCSP RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:PulSAR® 標(biāo)準(zhǔn)包裝:1,000 系列:- 位數(shù):12 采樣率（每秒）:300k 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:1 功率耗散（最大）:75mW 電壓電源:單電源 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:24-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:24-SOIC 包裝:帶卷 (TR) 輸入數(shù)目和類型:1 個(gè)單端，單極；1 個(gè)單端，雙極 |
| AD7651ACPZRL | 功能描述:IC ADC 16BIT UNIPOLAR 48LQFP RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:PulSAR® 標(biāo)準(zhǔn)包裝:1,000 系列:- 位數(shù):12 采樣率（每秒）:300k 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:1 功率耗散（最大）:75mW 電壓電源:單電源 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:24-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:24-SOIC 包裝:帶卷 (TR) 輸入數(shù)目和類型:1 個(gè)單端，單極；1 個(gè)單端，雙極 |
| AD7651AST | 制造商:Rochester Electronics LLC 功能描述:16-BIT 100KSPS SAR UNIPOLAR ADC W/REEL - Tape and Reel 制造商:Analog Devices 功能描述: 制造商:Analog Devices 功能描述:16BIT SAR ADC REF 7651 LQFP48 |
| AD7651ASTRL | 制造商:Analog Devices 功能描述: |
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