NTE2050 & NTE2051
Integrated Circuit
3
1
/
2
Digit Single Chip A/D Converter
Description:
The NTE2050 and NTE2051 are high performance, low power 31/2 digit A/D converters containing
all the necessary active devices on a single CMOS IC. Included are seven segment decoders, display
drivers, reference and a clock. The NTE2051 is designed to interface with a liquid crystal display
(LCD) and includes a backplane drive; the NTE2050 will directly drive an instrumentsize light emit-
ting diode (LED) display.
The NTE2050 and NTE2051 bring together an unprecedented combination of high accuracy, versatil-
ity, and true economy. High accuracy like autozero to less than 10
V, zero drift of less than 1
V/
C,
input bias current of 10pA max., and rollover error of less than one count. The versatility of true differ-
ential input and reference is useful in all systems, but gives the designer an uncommon advantage
when measuring load cells, strain gauges and other bridgetype transducers. And, finally, the true
economy of single power supply operation (NTE2051), enabling a high performance panel meter to
be built with the addition of only 7 passive components and a display.
Features:
D
Guaranteed Zero Reading for 0 Volts Input on all Scales
D
True Polarity at Zero for Precise Null Detection
D
Input Current: 1pA Typ
D
True Differential Input and Reference
D
Direct Display Drive No External Components Required:
NTE2050 (LED)
NTE2051 (LCD)
D
Low Noise Less than 15
V
PP
D
OnChip Clock and Reference
D
Low Power Dissipation Typically Less than 10mW
D
No Additional Active Circuits Required
Absolute Maximum Ratings:
Supply Voltage,
NTE2051, V+ to V
15V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NTE2050, V+ to GND
+6V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NTE2050, V to GND
9V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Input Voltage (Either Input, Note 2)
V+ to V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference Input Voltage (Either Input)
V+ to V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clock Input,
NTE2051
TEST to V+
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NTE2050
GND to V+
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation (Note 3)
800mW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Temperature Range
0
to +70
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range
65
to +160
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (During Soldering, 60sec)
+300
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Note 1. Stresses above those listed under "Absolute Maximum Ratings" may cause permanent
damage to the device. These are stress ratings only, and functional operation of the device
at these or another conditions above those indicated in the operational section of the specifi-
cation is not implied. Exposure to absolute maximum rating conditions for extended periods
may affect device reliability.
Note 2. Input voltages may exceed the supply voltages provided the input current is limited to
100
A.
Note 3. Dissipation rating assumes device is mounted with all leads soldered to printed circuit board.
Electrical Characteristics: (T
A
= +25
C, f
clock
= 48kHz unless otherwise specified)
Parameter
Test Conditions
Min
Typ
Max
Unit
Zero Input Reading
V
IN
= 0V
Full Scale = 200mV
000.0
000.0
+000.0 Digital Reading
Ratiometric Reading
V
IN
= V
REF
V
REF
= 100mV
999
999/1000
1000
Digital Reading
Rollover Error (Difference in
Reading for Equal Positive and
Negative Reading near Full
Scale)
V
IN
= +V
IN
]
200mV
1
.2
+1
Counts
Linearity (Maximum Deviation
from Best Straight Line Fit)
Full Scale = 200mV
or Full Scale = 2V
1
.2
+1
Counts
Common Mode Rejection Ratio
V
CM
=
1V, V
IN
= 0V
Full Scale = 200mV
50
V/V
Noise (PeakPeak Value not
Exceeded 95% of Time)
V
IN
= 0V
Full Scale = 200mV
15
V
Leakage Current | Input
V
IN
= 0
1
10
pA
Zero Reading Drift
V
IN
= 0, 0
< T
A
< +70
C
0.2
1.0
V/
C
Scale Factor Temperature
Coefficient
V
IN
= 199.0mV
0
< T
A
< +70
C
(Ext. Ref. 0ppm/
C)
1
5
ppm/
C
V+ Supply Current (Does Not
Include LED Current for
NTE2050)
V
IN
= 0
0.8
1.8
mA
V Supply Current (NTE2050 Only)
0.6
1.8
mA
Electrical Characteristics (Cont'd): (T
A
= +25
C, f
clock
= 48kHz unless otherwise specified)
Parameter
Test Conditions
Min
Typ
Max
Unit
Analog Common Voltage Common
(With Respect to Positive Supply)
25k
Between Common
& Positive Supply
2.4
2.8
3.2
V
Temperature Coefficient of Analog
Common (With Respect to
Positive Supply)
25k
Between Common
& Positive Supply
80
ppm/
C
PeakPeak Segment Drive Voltage,
PeakPeak Backplane Drive
Voltage (NTE2051 Only)
V+ to V = 9V, Note 4
4
5
6
V
Segment Sinking Current
(NTE2050 Only)
(Except Pin19)
(Pin19 Only)
V+ = 5V
Segment Voltage = 3V
5
10
8
16
mA
Note 4. Back plane drive is in phase with segment drive for "off" segment, 180
outp of phase for "on"
segment. Frequency is 20 times conversion rate. Average DC component is less than
50mV.
Pin Connection Diagram
A/Z
Units E1
OSC 1
Units A1
Units B1
Units C1
Units F1
Ref High
C ()
Units G1
OSC 3
Units D1
1
2
3
4
5
6
7
40
39
38
37
OSC 2
Test
36
35
Ref Low
34
C (+) Ref
8
33
Tens D2
Common
9
32
Tens B2
In Low
Tens C2
10
31
In High
11
30
Tens A2
12
29
BP/GND*
100's B3
Tens F2
Tens E2
Buff
G2 Tens
100's D3
13
14
15
28
27
Int
26
V ()
16
25
100's F3
C3 100's
17
24
AB4
G3 100's
100's E3
18
23
A3 100's
19
22
Polarity ()
20
21
Units V(+)
Note: Pin21 is GND on the NTE2050
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