7A16P
The Tektronix 7A16P is a single channel, programmable, vertical amplifier for 7000-series digitizing mainframes. All functions of the 7A16P can be remotely programmed via the GPIB 7000-series main interface bus, with exception of the variable gain control and the probe identify switch. It is special among the 7000-series vertical amplifiers since it offers a switchable 1 MΩ/50 Ω input impedance, only paralleled by the 7A42. The 7A16P is also unique as it has two input BNC connectors, but is strictly a single channel plugin, but having a switch that routes one of the BNC connectors to the amplifier circuits. This feature is handy in remote-controlled digitizing applications.
It was mainly intended for use in the 7612D and the 7912 family, but can also be used in the 7854 if paired with a 021-0374-00 and internally modified by adding cables for a 18 pin header and setting jumpers correctly. It is not recommended to use the 7A16P in any conventional 7000-series mainframe since it expects +5.1 V at pins B27 and A9 of the mainframe interface, and shorts them together. A9 is the 5V light pin on conventional mainframes, and its current rating might be too low for successful operation of the 7A16P.
Key Specifications
| Bandwidth 1 MΩ | 0 – 150 MHz |
|---|---|
| Bandwidth 50 Ω | 0 – 200 MHz |
| Deflection | 10 mV/Div to 5 V/Div in 1–2–5 sequence |
| Input impedance | 1 MΩ |
| Features |
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Internals
The input stage of the 7A16P contains miniature relays switching between the two available input connectors and selecting the AC and DC coupling modes. Another relay is used to enter a 50 Ω shunt if the corresponding input impedance is selected. Relays then select an optional 10x attenuator before entering the input buffer. This buffer contains an AC coupled MOSFET common drain amplifier and a DC coupled operational amplifier, configured in a feed-beside scheme. Gain switching is accommodated by several junction FETs to enter another 10x attenuator in front of the MOSFET buffer, and to enter 2x and 5x low impedance attenuators after the input buffer.
The digital circuitry is build around a Motorola 6800 processor with several MC6821 to drive the switches of the analog circuits and interfacing the modified 7000-series internal GPIB bus.
Links
Pictures
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7A16P front panel
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7A16P left internal
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7A16P right internal
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7A16P right internal modified with cables for connection to 021-0374-00.
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7A16P right internal modified for 021-0374-00, detail.
Firmware (uploaded BIN files)
- 160-1511-00.bin (U30630 and U31630 in 7A16P)
- 160-1512-00.bin (U30830 and U31830 in 7A16P)