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| 型号： | ADR421ARZ-REEL7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 17/24页 |
| 文件大小： | 0K |
| 描述： | IC VREF SERIES PREC 2.5V 8-SOIC |
| 设计资源： | 40 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5380 (CN0007) 40 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5381 (CN0010) 32 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5382 (CN0011) 32 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5383 (CN0014) 8 to 16 Channels of Programmable Voltage with Excellent Temperature Drift Performance Using AD5390/1/2 (CN0029) High Precision Digital-to-Analog Conversion Using the 16-Bit AD5542/1, ADR421, and AD8628 (CN0079) 16 Channels of Programmable Output Span Using AD5360 (CN0131) Layout Considerations for an Expandable Multichannel Simultaneous Sampling Data Acquisition System Based on AD7606 (CN0148) 40 Channels of Programmable Output Span Using AD5371 (CN0149) Software Calibrated, 1 MHz to 8 GHz, 70 dB RF Power Measurement System Using AD8318 (CN0150) How to Achieve High Precision Voltage Level Setting Using AD5541A/42A (CN0169) |
| 标准包装： | 1,000 |
| 系列： | XFET® |
| 基准类型： | 串联，精度 |
| 输出电压： | 2.5V |
| 容差： | ±0.12% |
| 温度系数： | 10ppm/°C |
| 输入电压： | 4.5 V ~ 18 V |
| 通道数： | 1 |
| 电流 - 静态： | 500µA |
| 电流 - 输出： | 10mA |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SO |
| 包装： | 带卷 (TR) |
ADR420/
ADR421/
V IN NIC
ADR425
NIC 3
ADR420/ADR421/
Data Sheet
THEORY OF OPERATION
The ADR42x series of references uses a reference generation
technique known as XFET (eXtra implanted junction FET).
This technique yields a reference with low supply current, good
thermal hysteresis, and exceptionally low noise. The core of the
XFET reference consists of two junction field-effect transistors
(JFET), one having an extra channel implant to raise its pinch-
off voltage. By running the two JFETs at the same drain current,
the difference in pinch-off voltage can be amplified and used to
form a highly stable voltage reference.
The intrinsic reference voltage is about 0.5 V with a negative
temperature coefficient of about ?120 ppm/°C. This slope is
essentially constant to the dielectric constant of silicon and can
be closely compensated by adding a correction term generated
in the same fashion as the proportional-to-temperature (PTAT)
term used to compensate band gap references. The primary
advantage over a band gap reference is that the intrinsic tem-
perature coefficient is approximately 30 times lower (therefore
requiring less correction). This results in much lower noise
because most of the noise of a band gap reference comes from
the temperature compensation circuitry.
temperature correction term is provided by a current source
with a value designed to be proportional to absolute tempera-
ture. The general equation is
V OUT = G × (? V P ? R1 × I PTAT ) (1)
where:
G is the gain of the reciprocal of the divider ratio.
? V P is the difference in pinch-off voltage between the two JFETs.
I PTAT is the positive temperature coefficient correction current.
Each ADR42x device is created by on-chip adjustment of R2
and R3 to achieve the specified reference output.
V IN
I 1 I 1
I PTAT
ADR423/ADR425
V OUT
R2
*
ADR420/ADR421/ADR423/ADR425
DEVICE POWER DISSIPATION CONSIDERATIONS
The ADR42x family of references is guaranteed to deliver load
currents to 10 mA with an input voltage that ranges from 4.5 V
to 18 V. When these devices are used in applications at higher
currents, the following equation should be used to account for
the temperature effects due to power dissipation increases:
T J = P D × θ JA + T A (2)
where:
T J and T A are the junction temperature and the ambient
temperature, respectively.
P D is the device power dissipation.
θ JA is the device package thermal resistance.
BASIC VOLTAGE REFERENCE CONNECTIONS
Voltage references, in general, require a bypass capacitor
illustrates the basic configuration for the ADR42x family of
references. Other than a 0.1 μF capacitor at the output to help
improve noise suppression, a large output capacitor at the
output is not required for circuit stability.
TP 1 8 TP
2 7
+ ADR423/
10μF 0.1μF OUTPUT
6
TOP VIEW 0.1μF
4 (Not to Scale) 5 TRIM
NIC = NO INTERNAL CONNECTION
TP = TEST PIN (DO NOT CONNECT)
Figure 39. Basic Voltage Reference Configuration
NOISE PERFORMANCE
The noise generated by ADR42x references is typically less
noise of the ADR421 , which is only 1.75 μV p-p. The noise
measurement is made with a band-pass filter made of a 2-pole
high-pass filter with a corner frequency at 0.1 Hz and a 2-pole
low-pass filter with a corner frequency at 10 Hz.
TURN-ON TIME
ΔV P
R1
R3
At power-up (cold start), the time required for the output
voltage to reach its final value within a specified error band
is defined as the turn-on settling time. Two components typi-
*EXTRA CHANNEL IMPLANT
V OUT = G(ΔV P – R1 × I PTAT )
Figure 38. Simplified Schematic
GND
cally associated with this are the time for the active circuits to
settle and the time for the thermal gradients on the chip to
stabilize. Figure 31 to Figure 35 show the turn-on settling time
Rev. J | Page 17 of 24
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADR421BR | 功能描述:IC VREF SERIES PREC 2.5V 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 电压基准 系列:XFET® 标准包装:2,000 系列:- 基准类型:旁路，可调节，精度 输出电压:1.24 V ~ 16 V 容差:±0.5% 温度系数:- 输入电压:1.24 V ~ 16 V 通道数:1 电流 - 阴极:100µA 电流 - 静态:- 电流 - 输出:20mA 工作温度:-40°C ~ 85°C 安装类型:通孔 封装/外壳:TO-226-3、TO-92-3（TO-226AA）成形引线 供应商设备封装:TO-92-3 包装:带卷 (TR) |
| ADR421BR-REEL7 | 功能描述:IC VREF SERIES PREC 2.5V 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电压基准 系列:XFET® 标准包装:3,000 系列:- 基准类型:旁路，精度 输出电压:3V 容差:±0.5% 温度系数:100ppm/°C 输入电压:- 通道数:1 电流 - 阴极:82µA 电流 - 静态:- 电流 - 输出:15mA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-TSSOP（5 引线），SC-88A，SOT-353 供应商设备封装:SC-70-5 包装:带卷 (TR) 其它名称:296-20888-2 |
| ADR421BRZ | 功能描述:IC VREF SERIES PREC 2.5V 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电压基准 系列:XFET® 标准包装:3,000 系列:- 基准类型:旁路，精度 输出电压:3V 容差:±0.5% 温度系数:100ppm/°C 输入电压:- 通道数:1 电流 - 阴极:82µA 电流 - 静态:- 电流 - 输出:15mA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-TSSOP（5 引线），SC-88A，SOT-353 供应商设备封装:SC-70-5 包装:带卷 (TR) 其它名称:296-20888-2 |
| ADR421BRZ | 制造商:Analog Devices 功能描述:Voltage Reference IC |
| ADR421BRZ-REEL7 | 功能描述:IC VREF SERIES PREC 2.5V 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电压基准 系列:XFET® 标准包装:3,000 系列:- 基准类型:旁路，精度 输出电压:3V 容差:±0.5% 温度系数:100ppm/°C 输入电压:- 通道数:1 电流 - 阴极:82µA 电流 - 静态:- 电流 - 输出:15mA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-TSSOP（5 引线），SC-88A，SOT-353 供应商设备封装:SC-70-5 包装:带卷 (TR) 其它名称:296-20888-2 |
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