MD3902/3905/3910
2/5/10MHz V/F Converters
Models MD3902/3905/3910 are high-
performance, precision 2/5/10MHz full-
scale voltage-to-frequency converters,
intended for those applications that
require maximum performance at the
most economical cost. These converters
feature >126/134/142-dB dynamic range,
±0.01/0.02/0.05%
linearity, and
±5%
overrange capability. The MD3902/3905/
3910 devices feature overall performance
and stability virtually identical to that of
similar units costing 40% or more.
All models accept a -100µV to -10V
full-scale single-ended analog input
signal that is converted to an output signal
whose frequency is proportional to the
full-scale frequency, within 0.01/0.02/
0.05% linearity, using the long-proven
charge-balance technique. The devices
offer 5% overrange capability, and
buffered complimentary TTL-compatible
frequency outputs that will drive capaci-
tive loads as high as 50 pF.
Stability of the MD3902/3905/3910
Series is excellent for V/F converters in
the respective price ranges, with 10µV/°C
typical, 30µV/°C maximum offset and
60 ppm/°C typical, 100 ppm/°C maxi-
mum gain temperature coefficients.
Warm-up time to specified accuracy
is less than two minutes.
In applications where overall system
throughput must be maintained at a
specific rate, or where fixed offset or
different scale voltages would be more
convenient, custom frequencies and/or
custom trimming can be easily accommo-
dated. By increasing the full-scale output
frequency by 10 to 20%, for example,
additional time would be available for
the system microprocessor to access the
results of each conversion. Please contact
the factory to discuss your specific timing
requirements.
All models are packaged in a 1.31" x
0.69" x 0.22" 24-pin ceramic DIL
package. Power dissipation is lower
than 0.65/0.80/0.85 watts, and operation
to specified accuracy is guaranteed over
the 0°C to +70°C temperature range.
Features:
s
Outstanding Price/
Performance Ratio
s
Guaranteed Minimum/
Maximum Specifications
s
Wide Dynamic Range
>2,000,000/5,000,000/
10,000,000:1
>126/134/142 dB
s
Excellent Linearity
±0.01/0.02/0.05%
FSR
±0.01/0.02/0.05%
of Input
10
µV/°C
Offset
60 ppm/°C Gain
s
Excellent Stability
s
Voltage or Current Inputs
s
Offset and Gain Error
Trimmable to Zero
s
Complementary Frequency
Outputs-TTL/CMOS
Compatible
s
Small 24-Pin DIP
s
Low Power <0.65/0.80/0.85W
Applications:
s
s
s
s
s
s
s
s
s
s
s
s
Precision Integration
Digital Data Transmission
Frequency Synthesis
Analytical Instrumentation
Medical Instrumentation
Telemetry
Data Recording
Weighing Systems
Tachometers
Accelerometers
Flow Meters
Robotics
For additional information
regarding Custom Microelectronic
Products and Services, please contact
Micro Networks at:
324 Clark St., Worcester, MA 01606
Tel. (508) 852-5400 • FAX (508) 853-8296
E-Mail – sales@mnc.com
Web Site – http://www.mnc.com
MD3902/3905/3910
2/5/10MHz V/F Converters
Absolute Maximum Ratings
Operating Temperature Range
Storage Temperature Range
+15V Supply (Pin 1)
-15V Supply (Pin 5)
+5V Supply (Pin 20)
Analog Input (Pin 11)
0°C to +70°C
-65°C to +150°C
+15.45 Volts
-15.45 Volts
+5.25 Volts
-15 Volts to +15 Volts
Ordering Information
Part Number
2MHz Full-scale
5MHz Full-scale
10MHz Full-scale
MD3902
MD3905
MD3910
Specifications @ T
A
= +25
°
C, Supplies =
±
15V and +5V, unless otherwise indicated
Specifications
Min.
ANALOG INPUTS
Input Voltage Range
Nonsaturating Overrange
Configuration
Input Impedance
Offset Voltage (trimmable to zero)
TRANSFER CHARACTERISTICS
Full-Scale Output
Transfer Function
Gain Error (trimmable to zero)
Nonlinearity (max.)
(not specified under
overrange conditions)
Full-Scale Step Response
(maximum; to 0.01%)
Overload Recovery
STABILITY
Gain Temperature Coefficient
Offset Temperature Coefficient
Power Supply Rejection
5
Typ.
0 to -10
Single-Ended
Max.
Units
Volts
%
kΩ
kΩ
kΩ
mV
MHz
MHz
MHz
MD3902
MD3905
MD3910
2
5
10
15
6
6
±7
±10
MD3902
MD3905
MD3910
MD3902
MD3905
MD3910
MD3902
MD3905
MD3910
MD3902
MD3905
MD3910
MD3902
MD3905
MD3910
2MHz•(V
IN
/ 10V)
5MHz•(V
IN
/ 10V)
10MHz•(V
IN
/ 10V)
±0.01%FS±0.01%V
IN
±0.02%FS±0.02%V
IN
±0.05%FS±0.05%V
IN
2 cycles of new f
OUT
+ 20µsec
2 cycles of new f
OUT
+ 10µsec
2 cycles of new f
OUT
+ 5µsec
8 cycles of new f
OUT
10 cycles of new f
OUT
12 cycles of new f
OUT
±1
%
60
10
Gain
Offset
200
80
35
+3.5
±14.55
+4.75
250
100
50
+4.0
Warm-up Time (to specified accuracy)
OUTPUT
Pulse Width
MD3902
MD3905
MD3910
Logic Levels: Logic “1”
Logic “0” (3 mA sink)
POWER SUPPLY REQUIREMENTS
±15V
Supplies
+5V Supply
+15V Current Drain
MD3902
MD3905
MD3910
-15V Current Drain
+5V Current Drain
MD3902
MD3905
MD3910
Power Dissipation
MD3902
MD3905
MD3910
100
30
200
10
2
300
120
65
+4.5
0.4
±15.45
±5.25
20
30
30
10
40
40
50
650
800
850
ppm of FSR/°C
ppm of FSR/°C
ppm of FSR/%Vs
µV/%Vs
Minutes
nsec
nsec
nsec
Volts
Volts
Volts
Volts
mA
mA
mA
mA
mA
mA
mA
mW
mW
mW
Specifications subject to change without notification as Micro Networks reserves the right to make improvements and changes in its products.
324 Clark St., Worcester, MA 01606
Tel. (508) 852-5400 • FAX (508) 853-8296
E-Mail – sales@mnc.com
Web Site – http://www.mnc.com
MD3902/3905/3910
2/5/10MHz V/F Converters
Block Diagram
(1)
+15V
AGND
-15V
+5V
DGND
(2,3,4)
(5)
(20)
OFFSET
Trim
(8)
Integrator
I
IN
V
IN
(10)
(22)
(11)
-
+
Charge
Pump
Schmidt
Trigger
(23,24)
OUTPUT
OUTPUT
Buffers
(21)
USING THE MD39XX
GENERAL CONSIDERATIONS
– Figure 2
depicts a typical circuit configuration for the
MD39XX. The layout should be clean, with
output pulses routed as far away from the input
analog signals as possible. To obtain maximum
performance, bypass capacitors, as shown in
Figure 2, should be mounted right at the
appropriate pins of the MD39XX.
+15V
Analog
Ground
-15V
6.8
µF
6.8
µF
OFFSET AND GAIN TRIMMING
– The Offset
adjustment potentiometer should be a 20kΩ,
10-turn unit. To ensure that the temperature
coefficient of the potentiometer does not become
significant relative to the overall offset tempco
specification, a 100ppm or better potentiometer is
recommended. With this pot in the circuit, initial
offsets of up to
±10mV
may be trimmed to zero.
The Gain adjustment potentiometer should be a
200Ω, 10-turn unit with a recommended tempera-
ture coefficient of 100ppm or better. With this pot
in the circuit, initial gain errors of up to
±2%
may
be trimmed to zero.
GROUNDING
– The Analog and Digital grounds
are internally separated in the MD39XX. The use
of ground plane is not necessary for proper
operation of the MD39XX. However, a ground
plane is recommended with any analog signal
conditioning circuitry that may be used in front
of the V/F, especially if this circuitry involves
high gains. Any amplifiers used ahead of the
MD39XX should be decoupled to eliminate
potential problems with the high-frequency
output of the V/F.
1
2
3
4
5
24
23
F
OUT
21
F
OUT
+5V
6.8
µF
20
22
Digital
Ground
20KΩ
10-Turn
<100 ppm/°
OFFSET
Trim
GAIN
Adjust
8
11
200KΩ
10-Turn
<100 ppm/°
Figure 2. Typical Circuit Configuration.
324 Clark St., Worcester, MA 01606
Tel. (508) 852-5400 • FAX (508) 853-8296
E-Mail – sales@mnc.com
Web Site – http://www.mnc.com
MD3902/3905/3910
2/5/10MHz V/F Converters
OFFSET AND GAIN CALIBRATION
OFFSET CALIBRATION
– Offset calibration
should be performed prior to gain calibration.
With a -10mV analog input signal at pin 11 of
the MD39XX, adjust the Offset potentiometer
until a frequency of 2.000/5.000/10.000kHz is
observed on output pins 21, 23 or 24.
GAIN CALIBRATION
– With a full scale
analog input voltage of -10.00V on pin 11,
adjust the Gain potentiometer until a full-scale
frequency of 2.000/5.000/10.000MHz is
observed on output pin 21, 23 or 24.
N/C PINS
– Pins marked as No Connect have no
electrical connection to the internal circuitry of
the MD39XX.
OUTPUT PINS
– Pins 23 and 24 are tied together
internally. Either or both may be used as the
source of the frequency output of the MD39XX,
as long as the load specifications are not
exceeded. Pin 21 provides a complementary
signal relative to pins 23 and 24 with similar
loading limits.
Pin Designations
1 +15V Supply
24 Output
Pin 1
24
2 Analog Ground 23 Output
3 Analog Ground 22 Digital Ground
4 Analog Ground 21 Output
5 -15V Supply
6 No Connect
7 No Connect
8 Offset Trim
9 No Connect
10 I
IN
20 +5V Supply
19 No Connect
18 No Connect
17 No Connect
16 No Connect
15 No Connect
14 No Connect
13 No Connect
12
13
11 V
IN
12 No Connect
324 Clark St., Worcester, MA 01606
Tel. (508) 852-5400 • FAX (508) 853-8296
E-Mail – sales@mnc.com
Web Site – http://www.mnc.com
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