1
TC7109
TC7109A
12-BIT
µ
P-COMPATIBLE ANALOG-TO-DIGITAL CONVERTERS
FEATURES
s
s
s
s
s
s
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s
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Zero-Integrator Cycle for Fast Recovery From
Input Overloads
Eliminates Cross -Talk in Multiplexed Systems
12-Bit Plus Sign Integrating A/D Converter With
Overrange Indication
Sign Magnitude Coding Format
True Differential Signal Input and Differential
Reference Input
Low Noise ............................................ 15
µ
V
P-P
Typ
Input Current .............................................. 1 pA Typ
No Zero Adjustment Needed
TTL-Compatible, Byte-Organized Tri-State
Outputs
UART Handshake Mode for Simple Serial Data
Transmission
GENERAL DESCRIPTION
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-
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
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-
formance and higher output drive capability than the origi-
nal TC7109. All new (or existing) designs should specify
the TC7109A wherever possible.
2
3
4
5
6
18
19
20
LBEN
HBEN
CE/LOAD
ORDERING INFORMATION
PART CODE
A or blank*
Package
Code
CKW
CLW
CPL
IJL
TC7109X
Temperature
Range
0°C to +70°C
0°C to +70°C
0°C to +70°C
–25°C to +85°C
Package
44-Pin PQFP
44-Pin PLCC
40-Pin Plastic DIP
40-Pin CerDIP
* The "A" version has a higher I
OUT
on the digital lines.
FUNCTIONAL BLOCK DIAGRAM
REF
IN +
36
AZ
ZI
INPUT 35
HI
INT
DE
(–)
AZ
DE
(+)
AZ
DE (±)
ZI
DE
(–)
DE
(+)
ZI
AZ
REF
IN –
39
AZ
ZI
R
CAZ
C INT
REF INT
CAP –
INT
BUFF AZ
32
30
31
38
BUFFER
–
+
INTEGRATOR
–
+
16 THREE-STATE OUTPUTS
COMPARATOR
COMP
OUT
14 LATCHES
12-BIT COUNTER
LATCH
CLOCK
POL
B12
B11
OR
B10
B9
B8
B7
B6
B5
B4
B3
REF
CAP +
37
17
3
4
5
6
7
8
9 10 11 12 13 14 15 16
B2
B1
C REF
TEST
HIGH-ORDER
BYTE OUTPUTS
LOW-ORDER
BYTE OUTPUTS
COMMON
33
7
HANDSHAKE
LOGIC
27
SEND
1
GND
TC7109A
10
µA
–
+
6.2V
TO
ANALOG
SECTION
INPUT 34
LO
INT
COMP OUT
AZ
INT
DE (±)
ZI
CONVERSION
CONTROL
LOGIC
OSCILLATOR
AND CLOCK
CIRCUITRY
29
28
40
V+
2
STATUS
26
22
23
24
25
21
REF V –
OUT
RUN/ OSC OSC OSC BUF MODE
HOLD IN OUT SEL OSC
OUT
8
TC7109/A-7 11/6/96
TELCOM SEMICONDUCTOR, INC.
3-91
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
