Subassembly > VM8DAC


VME Module


Ordering Information

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Low Noise
Digital to Analog Converter






VM8DAC VMEbus digital to analog converter (DAC) boards from Frequency Devices Inc. offer eight channels of precision low distortion/low noise, digital to analog converters that operate with a sample clock frequency derived from a master external clock and a programmable time base divider. The boards are available in a single width B-size (6U) VME form factor that conforms to VMEbus Revision C.1 as an A32/D32 Data Transfer Bus Slave.

VM8DAC boards provide high (24-bit) and low (16-bit) resolution data access to on-board DAC's. The boards interpret the received parallel data from the VMEbus as binary-2's complement. This data is serialized and transferred to any selected DAC channel at a fixed master time base where it is converted to analog signals at a software programmable sampling rate. The DAC channels may be configured to 16,384, 8,192, 4,096, or 2,048 samples per second.



  • Eight discrete channels with programmable sampling that provide a 24- bit DAC stage for each channel offers the user versatile and convenient digital to analog conversion.
  • Outputs synchronized to the front panel external clock allow for multi-card synchronicity.
  • Designed for Real Time Operating Systems (RTOS) to provide minimal pipeline delay (less than 5 microseconds). i.e. Linux or Vx Works.
  • Interrupt free operation provides glitch energy of <5nV-sec and extremely low noise density (<= 100nV/ ).
  • VME backplane is galvanically isolated from the analog section to reduce system integration problems.

VMDAC Ordering Guide

To Order, simply specify the part number below:




(@ 25°C and rated power input)


Module Size/Dimensions
1. Standard 6U VME, single slot module 9.17" X 6.3", (233mm X 160 mm)
2. Weight ~ 1 lb.
3. Input clock connector Lemo EPG.OB.302.HLN
4. Analog output connector Male DB25
5. Matching output connector Female DB25
External Clock Input
6. Configuration Differential, TTL compatible
7. Isolation Transformer isolated
8. Frequency 222 Hz (4.194305 MHz)
Analog Output
9. Number of channels per board 8
10. Analog output configuration Differential
11. Minimum output load 500 W
12. Maximum output voltage +/- 10V into 10 kW
13. Output amplifier 3 dB bandwidth >50KHz
14. Output impedance 50Ω per leg
15. Anti-image filter None
16. Inter-channel crosstalk < -90dB (frequencies less than 50KHz)
DAC Specifications
17. Number of bits 24 bits
18. Binary number format Binary 2's complement
19. Sampling rate 16,384, 8192, 4096, 2048 samples per second
20. Bipolar zero error ±2% F.S. maximum
21. Bipolar zero error drift ± 5 ppm of FS/ °C
22. Glitch energy < 5nV-sec
23. Output-referred noise < 100nV/ (40 Hz to 8192 Hz with FS 1000 Hz sine wave)
24. Amplitude match and accuracy ± 0.1 dB
25. Harmonic spikes <-100 dB (referred to a full scale output signal )
26. Output settling time to 1% < 5 microseconds (From output clock edge)
Power Requirements
27. From the + 5V VME backplane supply 1.0 A Max.
28. From the +/- 12V VME backplane supply 1.0 A
VME Interface
29. Interface configuration A32/D32 VME Data Transfer Bus (DTB) Slave
30. Address modifier lines decoding Full decode (0x09, 0x0A, 0x0D, and 0x0E valid)
31. Data word size Long word (Quad Byte) and aligned word (Double Byte)
32. Bus cycle compatibility AO, RMW, bus cycles address pipelining
33. Addressing modes A32 (Extended) addressing only
34. Operating Temperature range 0oC to +70oC
35. Storage Temperature range -25oC to +85oC
36. Humidity 0-95% non-condensing


We hope the information given here will be helpful. The information is based on data and our best knowledge, and we consider the information to be true and accurate. Please read all statements, recommendations or suggestions herein in conjunction with our conditions of sale which apply to all goods supplied by us. We assume no responsibility for the use of these statements, recommendations or suggestions, nor do we intend them as a recommendation for any use which would infringe any patent or copyright.

Frequency Devices, Inc.
Your engineering partner for signal conditioning
  927 Fosse Rd
Ottawa, IL 61350



Phone: (815) 434-7800

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