TC835
Personal Computer Data Acquisition A/D Converter
Features
•
•
•
•
•
•
•
•
Upgrade of Pin-Compatible TC7135, ICL7135
200kHz Operation
Single 5V Operation With TC7660
Multiplexed BCD Data Output
UART and Microprocessor Interface
Control Outputs for Auto-Ranging
Input Sensitivity: 100µV
No Sample and Hold Required
General Description
The TC835 is a low power, 4-1/2 digit (0.005%
resolution), BCD analog to digital converter (ADC) that
has been characterized for 200kHz clock rate opera-
tion. The five conversions per second rate is nearly
twice as fast as the ICL7135 or TC7135. The TC835,
like the TC7135, does not use the external diode resis-
tor rollover error compensation circuits required by the
ICL7135.
The multiplexed BCD data output is perfect for interfac-
ing to personal computers. The low cost, greater than
14-bit high-resolution and 100µV sensitivity makes the
TC835 exceptionally cost-effective.
Microprocessor-based data acquisition systems are
supported by the BUSY and STROBE outputs, along
with the RUN/HOLD input of the TC835. The
OVERRANGE, UNDERRANGE, BUSY and RUN/
HOLD control functions, plus multiplexed BCD data
outputs, make the TC835 the ideal converter for
µP-
based scales, measurement systems and intelligent
panel meters.
The TC835 interfaces with full function LCD and LED
display decoder/drivers. The UNDERRANGE and
OVERRANGE outputs may be used to implement an
auto-ranging scheme or special display functions.
Applications
• Personal Computer Data Acquisition
• Scales, Panel Meters, Process Controls
• HP-IL Bus Instrumentation
Device Selection Table
Part Number
TC835CBU
TC835CKW
TC835CPI
Note:
Package
64-PinPQFP
44-PinPQFP
28-Pin PDIP
Temperature Range
0°C to +70°C
0°C to +70°C
0°C to +70°C
Tape and Reel available for 44-Pin PQFP
package.
2002 Microchip Technology Inc.
DS21478B-page 1
©
TC835
Package Type
28-Pin PDIP
V-
1
REF IN
2
ANALOG
3
COM
INT OUT
4
AZ IN
5
BUFF OUT
6
C
REF
-
7
C
REF
+
8
–INPUT
9
+INPUT
10
V+
11
(MSD) D5
12
(LSB) B1
13
B2
14
28
UNDERRANGE
44-Pin PQFP
NC
ANALOG
COMMON
REF IN
STROBE
OR
NC
NC
UR
NC
26
STROBE
25
RUN/HOLD
24
DIGTAL GND
23
POLARITY
44 43 42 41 40 39 38 37 36 35 34
NC
1
INT OUT
2
AZ IN
3
BUFF OUT
4
REF CAP–
5
REF CAP+
6
–INPUT
7
+INPUT
8
V+
9
NC
10
NC
11
12 13 14 15 16 17 18 19 20 21 22
NC
33
NC
32
NC
31
RUN/HOLD
30
DGND
29
POLARITY
28
CLK IN
27
BUSY
26
D1 (LSD)
25
D2
24
NC
23
NC
TC835CPI
22
CLOCK IN
21
BUSY
20
D1 (LSD)
19
D2
18
D3
17
D4
16
B8 (MSD)
15
B4
TC835CKW
NC
NC
B2
B4
V–
27
OVERRANGE
D4
D3
NC
(MSD) D5
(LSB) B1
64-Pin PQFP
RUN/HOLD
STROBE
CLK IN
DGND
BUSY
SUB
POL
NC
NC
NC
NC
NC
NC
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
NC
1
NC
2
NC
3
NC
4
NC
5
NC
6
OVERRANGE
7
UNDERRANGE
8
SUB
9
V–
10
REF IN
11
ANALOG COM
12
NC
13
NC
14
NC
15
NC
16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
NC
D1
D2
48
NC
47
NC
46
NC
45
D3
44
D4
43
B3
42
B4
41
B2
40
SUB
39
B1
38
D5
37
NC
36
NC
35
NC
34
NC
33
NC
TC835CBU
BUFF
OUT
INT OUT
NC
AZ IN
NC
NC
BUF CAP–
NC
BUF CAP+
NOTES:
1. NC = No internal connection.
2. Pins 9, 25, 40 and 56 are connected to the die substrate. The potential at these pins is approximately V+.
No external connections should be made.
©
DS21478B-page 2
+INPUT
SUB
NC
–INPUT
NC
NC
V+
(MSB) B8
2002 Microchip Technology Inc.
NC
TC835
Typical Application
Address Bus
Control
Data Bus
+5V
V+ REF CAP
PA0
PA1
PA2
HCTS157
1Y
1B
2B
2Y
3Y
3B
S
1A
2A
3A
POL
OR
INT
UR
D5
B8
INPUT+
B4
B2
TC835
BUF
AZ
+15V -15V
DG529
D
A
D
B
WR
REF Voltage
Channel 1
Channel 2
Channel 3
R 6522 P
PA3
PA4
PA5
PA6
PA7
CA1
CA2
B1
D1
V
R
D2
Input
D3
D4
Analog
STB Common
R/H
F
IN
DGND
F
IN
- 5V
Channel 4
A
1
A
0
EN
Differential
Multiplexer
PB0 PB1 PB2 PB3
Channel Selection
2002 Microchip Technology Inc.
DS21478B-page 3
©
TC835
1.0
ELECTRICAL
CHARACTERISTICS
*Stresses above those listed under "Absolute Maximum Rat-
ings" may cause permanent damage to the device. These are
stress ratings only and functional operation of the device at
these or any other conditions above those indicated in the
operation sections of the specifications is not implied. Expo-
sure to Absolute Maximum Rating conditions for extended
periods may affect device reliability.
Absolute Maximum Ratings*
Positive Supply Voltage......................................... +6V
Negative Supply Voltage ........................................ -9V
Analog Input Voltage (Pin 9 or 10) ... V+ to V– (Note 2)
Reference Input Voltage (Pin 2) ..................... V+ to V–
Clock Input Voltage ........................................ 0V to V
+
Operating Temperature Range................0°C to +70°C
Storage Temperature Range ............. -65°C to +150°C
Package Power Dissipation (T
A
≤
70°C)
28-Pin Plastic DIP ............................ 1.14Ω
44-Pin PQFP .................................... 1.00Ω
64-Pin PQFP .................................... 1.14Ω
TC835 ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
T
A
= +25°C, F
CLOCK
= 200kHz, V+ = +5V, V- = -5V, unless otherwise specified.
Symbol
Analog
Display Reading with Zero Volt Input
TC
Z
TC
FS
NL
DNL
±FSE
I
IN
e
N
Digital
I
IL
I
IH
V
OL
V
OH
Input Low Current
Input High Current
Output Low Voltage
Output High Voltage;
B
1
, B
2
, B
4
, B
8
, D
1 –
D
5
Busy, Polarity, Overrange,
Underrange, Strobe
Clock Frequency
—
—
—
2.4
4.9
0
10
0.08
0.2
4.4
4.99
200
100
10
0.4
5
5
1200
µA
µA
V
V
V
kHz
V
IN
= 0V
V
IN
= +5V
I
OL
= 1.6mA
I
OH
= 1mA
I
OH
= 10µA
Note 10
Zero Reading Temperature Coefficient
Full-Scale Temperature Coefficient
Nonlinearity Error
Differential Linearity Error
Display Reading in Ratiometric Operation
± Full Scale Symmetry Error (Rollover Error)
Input Leakage Current
Noise
-0.0000
—
—
—
—
—
—
—
±0.0000 +0.0000 Display Reading
Note 3, Note 4
0.5
—
0.5
0.01
0.5
1
15
2
5
1
—
1
10
—
µV/°C
ppm/°C
Count
LSB
Count
pA
µV
P-P
V
IN
= 0V,
(Note 5)
V
IN
= 2V;
(Note 5, Note 6
Note 7
Note 7
–V
IN
= +V
IN
,
(Note 8)
Note 4
Peak to Peak Value not
Exceeded 95% of Time
Parameter
Min
Typ
Max
Unit
Test Conditions
+0.9996 +0.9998 +1.0000 Display Reading V
IN
= V
REF
,
(Note 3)
f
CLK
Note 1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
Functional operation is not implied.
Limit input current to under 100 µA if input voltages exceed supply voltage.
Full scale voltage = 2V.
V
IN
= 0V.
0°C
≤
T
A
≤
+70°C.
External reference temperature coefficient less than 0.01ppm/°C.
-2V
≤
V
IN
≤
+2V. Error of reading from best fit straight line.
|V
IN
| = 1.9959.
Test circuit shown in Figure 1-1.
Specification related to clock frequency range over which the TC835 correctly performs its various functions. Increased
errors result at higher operating frequencies.
©
DS21478B-page 4
2002 Microchip Technology Inc.
TC835
TC835 ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics:
T
A
= +25°C, F
CLOCK
= 200kHz, V+ = +5V, V- = -5V, unless otherwise specified.
Symbol
Power Supply
V+
V–
I+
I–
PD
Positive Supply Voltage
Negative Supply Voltage
Positive Supply Current
Negative Supply Current
Power Dissipation
4
-3
—
—
—
5
-5
1
0.7
8.5
6
-8
3
3
30
V
V
mA
mA
mΩ
f
CLK
= 0Hz
f
CLK
= 0Hz
f
CLK
= 0Hz
Parameter
Min
Typ
Max
Unit
Test Conditions
Note 1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
Functional operation is not implied.
Limit input current to under 100 µA if input voltages exceed supply voltage.
Full scale voltage = 2V.
V
IN
= 0V.
0°C
≤
T
A
≤
+70°C.
External reference temperature coefficient less than 0.01ppm/°C.
-2V
≤
V
IN
≤
+2V. Error of reading from best fit straight line.
|V
IN
| = 1.9959.
Test circuit shown in Figure 1-1.
Specification related to clock frequency range over which the TC835 correctly performs its various functions. Increased
errors result at higher operating frequencies.
2002 Microchip Technology Inc.
DS21478B-page 5
©
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