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参数资料
| 型号： | TC7129CLW |
| 元件分类： | ADC |
| 英文描述： | 1-CH DUAL-SLOPE ADC, ACCESS, PQCC44 |
| 封装： | PLASTIC, LCC-44 |
| 文件页数： | 13/17页 |
| 文件大小： | 185K |
| 代理商： | TC7129CLW |
5
TC7129
4-1/2 DIGIT ANALOG-TO-DIGITAL
CONVERTER WITH ON-CHIP LCD DRIVERS
PIN DESCRIPTIONS
Pin No.
40-Pin
44-Pin
TC7129CPL
TC7129CKW
TC7129CLW
Symbol
Function
34
32
38
REF HI
Positive reference voltage in
35
33
39
REF LO
Negative reference voltage
36
34
40
DGND
Internal ground reference for digital section. See "
±5V Power
Supply" paragraph.
37
35
41
RANGE
3
A pulldown for 200mV scale. Pulled HI externally for 2V
scale.
38
36
42
DP2
Internal 3
A pulldown. When HI, decimal point 2 will be on.
39
37
43
DP1
Internal 3
A pulldown. When HI, decimal point 1 will be on.
40
38
44
OSC2
Output of first clock inverter. Input of second clock inverter.
6,17, 28, 39
12, 23, 34,1
NC
No Connection
COMPONENT SELECTION
(All pin designations refer to 40-Pin DIP)
The TC7129 is designed to be the heart of a high-
resolution analog measurement instrument. The only addi-
tional components required are a few passive elements, a
voltage reference, an LCD, and a power source. Most
component values are not critical; substitutes can be chosen
based on the information given below.
The basic circuit for a digital multimeter application is
shown in Figure 1. See "Special Applications" for variations.
Typical values for each component are shown. The sections
below give component selection criteria.
Oscillator (XOSC, CO1, CO2, RO)
The primary criterion for selecting the crystal oscillator
is to chose a frequency that achieves maximum rejection of
line-frequency noise. To do this, the integration phase
should last an integral number of line cycles. The integration
phase of the TC7129 is 10,000 clock cycles on the 200mV
range and 1000 clock cycles on the 2V range. One clock
cycle is equal to two oscillator cycles. For 60Hz rejection, the
oscillator frequency should be chosen so that the period of
one line cycle equals the integration time for the 2V range:
1/60 second = 16.7 msec =
1000 clock cycles
2 osc cycles/clock cycle
oscillator frequency
giving an oscillator frequency of 120kHz. A similar calcula-
tion gives an optimum frequency of 100kHz for 50Hz rejec-
tion.
*
,
The resistor and capacitor values are not critical; those
shown work for most applications. In some situations, the
capacitor values may have to be adjusted to compensate for
parasitic capacitance in the circuit. The capacitors can be
low-cost ceramic devices.
Some applications can use a simple RC network instead
of a crystal oscillator. The RC oscillator has more potential
for jitter, especially in the least significant digit. See "RC
Oscillator."
Integrating Resistor (RINT)
The integrating resistor sets the charging current for
the integrating capacitor. Choose a value that provides a
current between 5
A and 20A at 2V, the maximum full-
scale input. The typical value chosen gives a charging
current of 13.3
A:
ICHARGE =
13.3
A
Too high a value for RINT increases the sensitivity to
noise pickup and increases errors due to leakage current.
Too low a value degrades the linearity of the integration,
leading to inaccurate readings.
2V
150k
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| TC7131CPL | 1-CH DUAL-SLOPE ADC, ACCESS, PDIP40 |
| TC7135C/PI | 1-CH 4-BIT DUAL-SLOPE ADC, PARALLEL ACCESS, PDIP28 |
| TC7135C/LI | 1-CH 4-BIT DUAL-SLOPE ADC, PARALLEL ACCESS, PQCC28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TC7129CLW713 | 功能描述:LCD 驱动器 w/LCD Driver RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| TC7129CPL | 功能描述:LCD 驱动器 w/LCD Driver RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| TC7129CPL713 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:4-1/2 Digit Analog-to-Digital Converters with On-Chip LCD Drivers |
| TC7129IJL713 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:4-1/2 Digit Analog-to-Digital Converters with On-Chip LCD Drivers |
| TC7129IKW713 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:4-1/2 Digit Analog-to-Digital Converters with On-Chip LCD Drivers |
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