NTE NTE890

NTE890
Integrated Circuit
Voltage to Frequency Converter
Description:
The NTE890 is an integrated circuit in an 8–Lead DIP type package and provides a simple method
of A/D conversion. It has all the inherent advantages of the voltage–to–frequency conversion technique. The output is a series of constant duration pulses. The frequency of the pulses is proportional
to the applied input voltage. This converter is designed for use in a wide range of data conversion
and remote sensing applications.
Absolute Maximum Ratings: (TA = +25°C unless otherwise specified)
Supply Voltage, V+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8V to 22V
Output Sink Current, ISINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mA
Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500mW
Input Voltage, Vi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.2V to V+(V)
Operating Temperature Range, Topr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –20° to +75°C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40° to +125°C
Electrical Characteristics: (V+ = +15V, TA = +25°C unless otherwise specified)
Parameter
Min
Typ
Max
Unit
8V < V+ < 15V
2.0
3.5
6.0
mA
15V < V+ < 22V
2.0
4.5
7.5
mA
Conversion Accuracy Scale Factor
VIN = 10V, RS = 14kΩ
0.9
1.0
1.1
kHz/V
Drift with Temperature
VIN = 10V
–
±100
–
ppM/°C
Drift with V+
VIN = 1V, 8V < V+ < 18V
–
0.2
1.0
%/V
–
5
10
mV
Offset Current
–
±50
±100
nA
Input Bias Current
–
–100
–300
nA
–
V
Supply Current
Test Conditions
Input Comparator Offset Voltage
Common Mode Range
One–Shot Threshold Voltage
Note 1
0 to V+ –3 0 to V+ –2
Pin5
0.63
0.66
0.70
x V+
Input Bias Current
Pin5
–
–100
–500
nA
Reset VSAT
Pin5, I = 2.2mA
–
0.15
0.50
V
Note 1 Input Common Mode Range includes GND.
Electrical Characteristics (Cont’d): (V+ = +15V, TA = +25°C unless otherwise specified)
Parameter
Min
Typ
Max
Unit
RS = 14kΩ, Pin1, V+ = 0V
–
138.7
–
µA
Change with Voltage
Pin1, V+ = 0V to 10V
–
1.0
2.5
µA
Off Leakage
Pin1, V+ = 0V
–
1
50
nA
Reference Voltage
Pin2
1.70
1.90
2.08
V
Pin3, I = 3mA
–
0.15
0.50
V
Pin3, I = 2mA
–
0.10
0.30
V
–
0.1
1.0
µA
Current Source
Output Current
Logic Output VSAT
VSAT
Test Conditions
Off Leakage
Note 2. The voltage applied to comparator input Pin6 and Pin7 should not be allowed to go below
GND by more than 300mV.
Note 3. Pin3 and Pin5 are open–collector outputs. Shorts between these pins and V+ can cause
overheating and eventual destruction.
Note 4. Reference voltage terminal Pin2 is connected to the emitter of an NPN transistor and is held
at approximately 1.9V. This terminal should be protected from accidental shorts to GND or
supply voltages. Permanent damage may occur if current in Pin2 exceeds 5mA.
Note 5. Avoid stray coupling between Pin5 and Pin7 which could cause false triggering. If false triggering is experienced with the precision mode circuits, bypass Pin6 to GND with at least
0.01µF. This is necessary for operation above 10kHz.
Pin Connection Diagram
8 VCC
Current Source 1
Scale Factor 2
7 Input Voltage
Logic Output 3
6 Threshold
GND 4
8
5 One–Shot R, C
5
.260 (6.6)
1
4
.390 (9.9)
Max
.300
(7.62)
.155
(3.93)
.100 (2.54)
.145 (3.68)
.300 (7.62)