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參數(shù)資料
| 型號： | TC7136 |
| 廠商： | TelCom Semiconductor, Inc. |
| 英文描述： | LOW POWER, 3-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTERS |
| 中文描述： | 低功耗，3-1/2數(shù)字模擬數(shù)字轉(zhuǎn)換器 |
| 文件頁數(shù)： | 9/12頁 |
| 文件大?。?/td> | 192K |
| 代理商： | TC7136 |
3-255
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
Component
Value Nominal Full-Scale Voltage
200mV
2V
C
AZ
R
INT
C
INT
NOTE:
f
OSC
= 48 kHz (3 readings per sec). R
OSC
= 180k
, C
OSC
= 50
0.47
μ
F
180 k
0.047
μ
F
0.1
μ
F
1.8 M
0.047
μ
F
output voltage back to zero during the reference integrate
phase, is stored on C
REF
. A 0.1
μ
F capacitor is acceptable
when V
–
mode voltage exists (V
–
application requires a 200 mV full scale, increase C
REF
to
1
μ
F. Roll-over error will be held to less than 0.5 count. A
Mylar-type dielectric capacitor is adequate.
REF
is tied to analog common. If a large common-
REF
≠
analog common) and the
Integrating Capacitor
(C
INT
)
C
INT
should be selected to maximize integrator output
voltage swing without causing output saturation. Analog
common will normally supply the differential voltage refer-
ence this case, a
±
2V full-scale integrator output swing is
satisfactory. For 3 readings per second (f
OSC
= 48 kHz) a
0.047
μ
F value is suggested. For one reading per second,
0.15
μ
F is recommended. If a different oscillator frequency
is used, C
INT
must be changed in inverse proportion to
maintain the nominal
±
2V integrator swing.
An exact expression for C
INT
is:
(
Oscillator Components
C
OSC
should be 50 pF. R
OSC
is selected from the
equation:
f
OSC
=
.
Note that f
OSC
is
4
4 to generate the TC7136A's internal
clock. The backplane drive signal is derived by dividing f
OSC
by 800.
To achieve maximum rejection of 60Hz noise pickup,
the signal integrate period should be a multiple of 60Hz.
Oscillator frequencies of 240kHz, 120kHz, 80kHz, 60kHz,
40kHz, etc. should be selected. For 50 Hz rejection, oscil-
lator frequencies of 200kHz, 100kHz, 66-2/3 kHz, 50kHz,
40kHz, etc. would be suitable. Note that 40kHz (2.5 read-
ings per second) will reject both 50Hz and 60Hz.
Reference Voltage Selection
A full-scale reading (2000 counts) requires the input
signal be twice the reference voltage.
0.45
RC
In some applications, a scale factor other than unity may
exist between a transducer output voltage and the required
digital reading. Assume, for example, a pressure transducer
output for 2000 lb/in.
2
is 400 mV. Rather than dividing the
input voltage by two, the reference voltage should be set to
200 mV. This permits the transducer input to be used
directly.
The differential reference can also be used when a
digital zero reading is required when V
IN
is not equal to zero.
This is common in temperature measuring instrumentation.
A compensating offset voltage can be applied between
analog common and V
–
between V
IN
The transducer output is connected
IN
and analog common.
DEVICE PIN FUNCTIONAL DESCRIPTION
Differential Signal Inputs
V
+
The TC7136/A is designed with true differential inputs
and accepts input signals within the input stage common-
mode voltage range (V
CM
). The typical range is V
+
–1V to V
–
+1V. Common-mode voltages are removed from the system
when the TC7136A operates from a battery or floating power
source (isolated from measured system), and V
IN
nected to analog common (V
COM
). (See Figure 7.)
IN
(Pin 31), V
–
(Pin 30)
–
is con-
Required Full-Scale Voltage*
V
REF
100 mV
1V
200 mV
2V
*V
FS
= 2 V
REF
.
where: f
OSC
= Clock frequency at pin 38
V
FS
= Full-scale input voltage
R
INT
= Integrating resistor
V
INT
= Desired full-scale integrator output swing.
C
INT
must have low dielectric absorption to minimize
roll-over error. A polypropylene capacitor is recommended.
Integrating Resistor
(R
INT
)
The input buffer amplifier and integrator are designed
with Class A output stages. The output stage idling current
is 6
μ
A. The integrator and buffer can supply 1
μ
A drive
currents with negligible linearity errors. R
INT
is chosen to
remain in the output stage linear drive region, but not so
large that PC board leakage currents induce errors. For a
200 mV full scale, R
INT
is 180 k
. A 2V full scale requires
1.8 M
.
C
INT
=
,
1
f
OSC
V
FS
R
INT
(
)
(4000)
V
INT
LOW POWER, 3-1/2 DIGIT
ANALOG-TO-DIGITAL CONVERTERS
TC7136
TC7136A
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TC7136 | Low Power 3-1/2 Digit Analog-to-Digital Converter |
| TC7136A | Low Power 3-1/2 Digit Analog-to-Digital Converter |
| TC7136ACLW | Low Power 3-1/2 Digit Analog-to-Digital Converter |
| TC7136ACPI | Low Power 3-1/2 Digit Analog-to-Digital Converter |
| TC7136CLW | Low Power 3-1/2 Digit Analog-to-Digital Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TC7136A | 制造商:TELCOM 制造商全稱:TelCom Semiconductor, Inc 功能描述:LOW POWER, 3-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTERS |
| TC7136ACKW | 功能描述:LCD 驅(qū)動器 Low Power RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| TC7136ACKW713 | 功能描述:LCD 驅(qū)動器 Low Power RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| TC7136ACLW | 功能描述:LCD 驅(qū)動器 Low Power RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| TC7136ACLW713 | 功能描述:LCD 驅(qū)動器 Low Power RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
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