MD3902 View Datasheet(PDF) - Micro Networks
Part Name
Description
MFG CO.
'MD3902' PDF : 4 Pages View PDF
MD3902/3905/3910
2/5/10MHz V/F Converters
OFFSET
Trim (8)
IIN (10)
VIN (11)
Block Diagram
Integrator
-
+
Charge
Pump
Schmidt
Trigger
Buffers
(1) +15V
(2,3,4) AGND
(5) -15V
(20) +5V
(22) DGND
(23,24) OUTPUT
(21) OUTPUT
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
1
6.8
2
Analog µF
Ground 6.8
3
4
µF
-15V
5
20KΩ
10-Turn
<100 ppm/°
8
OFFSET
Trim
GAIN
Adjust
11
24
FOUT
23
21
FOUT
20
+5V
6.8
22
µF Digital
Ground
200KΩ
10-Turn
<100 ppm/°
Figure 2. Typical Circuit Configuration.
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.
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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