TC7109 Datasheet, PDF (1/21 Pages) TelCom Semiconductor, Inc – 12-BIT UP-COMPATIBLE ANALOG-TO-DIGITAL CONVERTERS

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TC7109
TC7109A
12-BIT µP-COMPATIBLE ANALOG-TO-DIGITAL CONVERTERS
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FEATURES
GENERAL DESCRIPTION
s Zero-Integrator Cycle for Fast Recovery From
Input Overloads
s Eliminates Cross -Talk in Multiplexed Systems
s 12-Bit Plus Sign Integrating A/D Converter With
Overrange Indication
s Sign Magnitude Coding Format
s True Differential Signal Input and Differential
Reference Input
s Low Noise ............................................ 15 µV_P-P Typ
s Input Current .............................................. 1 pA Typ
s No Zero Adjustment Needed
s TTL-Compatible, Byte-Organized Tri-State
Outputs
s UART Handshake Mode for Simple Serial Data
Transmission
ORDERING INFORMATION
PART CODE
A or blank*
TC7109X
Package
Code
CKW
Package
44-Pin PQFP
Temperature
Range
0°C to +70°C
The TC7109A is a 12-bit plus sign, CMOS low-power
analog-to-digital converter (ADC). Only eight passive com-
ponents and a crystal are required to form a complete
dual-slope integrating ADC.
The improved V_OH source current TC7109A has fea-
3 ^{tures that make it an attractive per-channel alternative to}
analog multiplexing for many data acquisition applica-
tions. These features include typical input bias current of
1pA drift of less than 1µV/°C, input noise typically 15µV_P-P,
and auto-zero. True differential input and reference allow
measurement of bridge-type transducers such as load
cells, strain gauges, and temperature transducers.
The TC7109A provides a versatile digital interface. In
4 ^{the direct mode, chip select and HIGH/LOW byte enables}
control parallel bus interface. In the handshake mode, the
TC7109A will operate with industry-standard UARTs in
controlling serial data transmission — ideal for remote
data logging. Control and monitoring of conversion timing
is provided by the RUN/HOLD input and STATUS output.
For applications requiring more resolution, see the
TC500, 15-bit plus sign ADC data sheet.
The TC7109A has improved overrange recovery per-
5 ^{formance and higher output drive capability than the origi-}
nal TC7109. All new (or existing) designs should specify
the TC7109A wherever possible.
CLW
44-Pin PLCC
0°C to +70°C
CPL
40-Pin Plastic DIP
0°C to +70°C
IJL
40-Pin CerDIP
–25°C to +85°C
* The "A" version has a higher I_OUT on the digital lines.
FUNCTIONAL BLOCK DIAGRAM
REF
CAP ⁺
37
REF
IN ⁺
36
CREF _REF
IN ^–
39
REF
CAP
RINT
–
38
30
BUF3F1
CAZ
AZ ₃₂
CINT
INT
17
INPUT ^{35 INT}
HI
AZ
AZ
ZI
ZI
DE DE
(–) (+)
BUFFER
–
+
INTEGRATOR
–
COMPARATOR
+
COMP
OUT
HIGH-ORDER
BYTE OUTPUTS
LOW-ORDER
BYTE OUTPUTS
3 4 5 6 7 8 9 10 11 12 13 14 15 16
16 THREE-STATE OUTPUTS
14 LATCHES
AZ
33
COMMON
INPUT ^{34 INT}
LO
DE DE
(+) (–)
AZ
DE (±)
ZI
ZI
AZ
TC7109A
COMP OUT
TO
AZ
10 µA
ANALOG
INT
SECTION
DE (±)
ZI
–
+
CONVERSION
CONTROL
LOGIC
12-BIT COUNTER
LATCH
CLOCK
OSCILLATOR
AND CLOCK
CIRCUITRY
HANDSHAKE
LOGIC
6.2V
18 _LBEN
19 _HBEN
20 _CE/LOAD
29 28
REF V–
OUT
40
V+
TELCOM SEMICONDUCTOR, INC.
2
STATUS
26
22 ₂₃ 24 ₂₅
21
RUN/ OSC OSC OSC BUF MODE
HOLD IN OUT SEL OSC
OUT
27
SEND
1
GND
TC7109/A-7 11/6/96
3-91
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