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参数资料
| 型号： | TC3402VQRRT |
| 元件分类： | ADC |
| 英文描述： | 4-CH 16-BIT DELTA-SIGMA ADC, SERIAL ACCESS, PDSO16 |
| 封装： | QSOP-16 |
| 文件页数： | 8/12页 |
| 文件大小： | 69K |
| 代理商： | TC3402VQRRT |
5
TC3402
+1.8V, Low-Power, Quad-Input,
16-Bit, Sigma-Delta, A/D Converter
TC3402-1 6/29/00
2001 Microchip Technology Inc.
DS21411A
GENERAL THEORY OF OPERATION
The TC3402 is a 16-bit sigma-delta A/D converter. It
has four differential inputs and an analog multiplexer. The
detailed description of the key components of the TC3402 is
outlined below. (Also refer to the
A/D Operational Flowchart
on page 9 and the Timing Diagrams in Figures 2 through 4).
A/D Converter Operation
When the TC3402 is not converting, it is in sleep mode
with both the SCLK and SDAT lines high. An A/D conversion
is initiated by a high to low transition on the SCLK line at
which time the internal clock of the TC3402 is started and
the address value (A0 and A1) is internally latched. The
address value steers the analog multiplexer to select the
input channel to be converted. Each additional high to low
transition of SCLK (following the initial SCLK falling edge)
and during the time interval t4 will decrement the conversion
accuracy by one bit and reduce the conversion time by one
half. The time interval t4 is referred to as the resolution
reduction window. The minimum conversion resolution is 10
bits so any more than 6 SCLK transitions during t4 will be
ignored.
After each high to low transition of SCLK, in the t4
interval, the SDAT output is driven high by the TC3402 to
acknowledge that the conversion has been decremented.
When the SCLK returns high or the t4 interval ends, the
SDAT line returns low (see Figure 2). When the conversion
is complete SDAT is driven high. The 3402 now enters sleep
mode and the conversion value can be read as a serial data
word on the SDAT line.
Reading the Data Word
After the conversion is complete and SDAT goes high,
the conversion value can be clocked serially onto the SDAT
line by high to low transitions of the SCLK. The data word is
in two’s compliment format with the sign bit clocked onto the
SDAT line first followed by the MSB and ending in the LSB.
For a 16 bit conversion the data word would consist of a sign
bit follwed by 15 magnitude bits, Table 1 shows the data
word versus input voltage for a 16 bit conversion. Note that
the full scale input voltage range is
±(2 REFIN– 1LSB). When
REFOUT is fed back directly to REFIN, an LSB is 73V for a
16 bit convertion, as REFOUT is typically 1.193V.
Figure 3 shows typical SCLK and SDAT waveforms for
16, 12 and 10 bit conversions. Note that any complete
convert and read cycle requires 17 negative edge clock
pulses. The first is the convert command. Then, up to six of
these can occur in the resolution reduction window, t4, to
decrement accuracy. The remaining pulses clock out the
conversion data word.
Table 1. Data Conversion Word vs. Voltage Input
(REFIN = 1.193V)
Data Word
INn+ – INn– (Volts)
0111 1111 1111 1111
2.38596 (Positive Full Scale)
0000 0000 0000 0001
72.8 E – 6
0000 0000 0000 0000
0
1111 1111 1111 1111
–72.8 E – 6
1000 0000 0000 0001
–2.38596 (Negative Full Scale)
1000 0000 0000 0000
Reserved Code
The SCLK input has a filter which rejects any positive or
negative pulse of width less than 50nsec to reduce noise.
The rejection width of this pulse can vary between 50nsec
and 750nsec depending on processing parameters and
supply voltage.
Figure 3 shows a truth table for determining the mode of
operation for the TC3402 part by recording the value of
SDAT for SCLK in a high, then low, then high state. For
example, if SCLK goes through a 1-0-1 transition and the
corresponding values of SDAT are 1-1-0, then the SCLK
falling edge started a new data conversion. A 0-1-0 for SDAT
would have indicated a resolution reduction had occurred.
This is useful if the microcontroller has a watchdog reset or
otherwise loses track of where the TC3402 part is in the
conversion and data readout sequence. The microcontroller
can simply transition SCLK until it “finds” a Start Conversion
condition.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC3402VQRTR | 功能描述:模数转换器 - ADC 16-Bit Sigma-Delta RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| TC3403 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:+1.8V Low Power, Quad Input, 16-Bit Sigma-Delta A/D Converter with a Power Fault Monitor and Microprocessor Reset Circuit |
| TC3403_05 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:+1.8V Low Power, Quad Input, 16-Bit Sigma-Delta A/D Converter with a Power Fault Monitor and Microprocessor Reset Circuit |
| TC3403VPE | 功能描述:模数转换器 - ADC 1.8V Lw Pwr Quad RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| TC3403VQR | 功能描述:模数转换器 - ADC 1.8V Lw Pwr Quad RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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