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M377: Difference between revisions
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|Manufacturer=Tektronix | |Manufacturer=Tektronix | ||
|Model=M377 | |Model=M377 | ||
|Part_nos= | |Part_nos=165-2129-03;165-2089-06;155-2089-05;165-2456-00 | ||
|Description=amplifier | |Description=amplifier | ||
|an=an | |an=an | ||
| Line 16: | Line 16: | ||
excellent variable gain control, two four pole bandwidth limits, three outputs which could be separately inverted and turned on or off. | excellent variable gain control, two four pole bandwidth limits, three outputs which could be separately inverted and turned on or off. | ||
It was the first wideband analog IC with level shift on chip (allowing 0 V common mode input and output and without PNP transistors), | It was the first wideband analog IC with level shift on chip (allowing 0 V common mode input | ||
first wideband amplifier with any on-chip bandwidth limit selection, first to have more than two fixed gain settings (it has six), | and output and without PNP transistors), first wideband amplifier with any on-chip bandwidth | ||
first to require only one transient response adjustment (no thermals), and the first to have a highly linear relationship between a control voltage and gain. It also had excellent overdrive recovery. | limit selection, first to have more than two fixed gain settings (it has six), first to require | ||
only one transient response adjustment (no thermals), and the first to have a highly linear | |||
relationship between a control voltage and gain. It also had excellent overdrive recovery. | |||
''(See also [[M777|John's comments on the M777 successor]].)'' | ''(See also [[M777|John's comments on the M777 successor]].)'' | ||
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Later, the M377 and M777 were also used in several other Tek instruments. | Later, the M377 and M777 were also used in several other Tek instruments. | ||
If the instrument has more than 300 MHz bandwidth at | If the instrument has more than 300 MHz bandwidth at 1 mV/div sensitivity, | ||
it can be assumed to be using the M777 which makes use of Tek's later IC fabrication process | it can be assumed to be using the M777 which makes use of Tek's later IC fabrication process | ||
that provides transistor with higher f<sub>t</sub>. | |||
The M377 and M777 are in the following instruments based on the specified bandwidth at | The M377 and M777 are in the following instruments based on the specified bandwidth at 1 mV/div: | ||
{| class="wikitable" | {| class="wikitable" | ||
|+ M377 | |+ M377 | ||
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|- | |- | ||
|} | |} | ||
== Links == | == Links == | ||
| Line 67: | Line 67: | ||
==Packaging of the M377== | ==Packaging of the M377== | ||
11000 series instruments and the | 11000 series instruments and the [[AM503A]] and [[AM503B]] use a 1.22 cm square, flat ceramic package compatible with the Hypcon connector. | ||
The ceramic rests on a heat sink supplied by the instrument’s chassis. | The ceramic rests on a heat sink supplied by the instrument’s chassis. | ||
| Line 76: | Line 76: | ||
* [[165-2089-06]] | * [[165-2089-06]] | ||
* [[155-2089-05]] (11A33) | * [[155-2089-05]] (11A33) | ||
* [[165-2456-00]] ( | * [[165-2456-00]] (AM503A as [[M694]], M377 with relaxed DC balance specs) | ||
* [[165-2456-00]] ( | * [[165-2456-00]] (AM503B as [[M694]], M377 with relaxed DCbalance specs) | ||
{| class="wikitable" | {| class="wikitable" | ||
| Line 101: | Line 101: | ||
|11A52 || B010180 - up || 165-2129-03 || 100 Ω || Diode bridge + 50 Ω input R + M377 chip | |11A52 || B010180 - up || 165-2129-03 || 100 Ω || Diode bridge + 50 Ω input R + M377 chip | ||
|- | |- | ||
| | |AM503A || B010101 - up || 165-2456-00 || 100 Ω || M377 chip only aka M694 (relaxed DC bal spec) | ||
|- | |- | ||
| | |AM503B || B010101 - up || 165-2456-00 || 100 Ω || M377 chip only aka M694 (relaxed DC bal spec) | ||
|- | |- | ||
|} | |} | ||
| Line 112: | Line 112: | ||
* Output invert | * Output invert | ||
* Output enable. When an output is disabled, it has no offset and maintains the specified termination impedance. That is, the internal parallel output termination remains connected, but the signal current is shut off. The self-calibration of 11k systems makes use of this property. | * Output enable. When an output is disabled, it has no offset and maintains the specified termination impedance. That is, the internal parallel output termination remains connected, but the signal current is shut off. The self-calibration of 11k systems makes use of this property. | ||
* High-frequency adjustment. The HF ADJ pins have | * High-frequency adjustment. The HF ADJ pins have 2 kΩ input resistance to ground. The nominally acceptable inputs are ±1 V to ground. Because the input resistance tracks the nichrome standard resistors inside the chip, the input is actually current sensitive, not that it makes much difference. This current affects the standing current in a feedback amplifier and hence its open loop gain. At low frequencies, the gain of the M377 is determined entirely by resistor values. At high frequencies, there is phase shift and changing the open loop gain will also change the closed loop gain, hence the transient response. | ||
==Var Gain Control Signal== | ==Var Gain Control Signal== | ||
| Line 121: | Line 121: | ||
==165-2089-xx Pinout== | ==165-2089-xx Pinout== | ||
In the 11A32, 11A34, and 11A52, pairs of 165-2089-xx IC are placed on the board so that their outputs are facing one another, | In the 11A32, 11A34, and 11A52, pairs of 165-2089-xx IC are placed on the board so that their | ||
allowing their outputs to be wired in parallel with a minimum of board complexity and asymmetry. | outputs are facing one another, allowing their outputs to be wired in parallel with a minimum | ||
of board complexity and asymmetry. | |||
The purpose of the three output channels varies depending on the rotational orientation of the IC on the board. | The purpose of the three output channels varies depending on the rotational orientation of the IC on the board. | ||
* Output 1 (pins 25 and 26) is either AUX SIG (aka AUX TRIGGER) or DISPLAY, | * Output 1 (pins 25 and 26) is either AUX SIG (aka AUX TRIGGER) or DISPLAY, | ||
| Line 133: | Line 134: | ||
Output 3 of U310 is in parallel with output 1 of U410. | Output 3 of U310 is in parallel with output 1 of U410. | ||
Note that in the 11A32 and 11A34, the HF ADJUST control voltages are not set identically for the three outputs. | Note that in the 11A32 and 11A34, the HF ADJUST control voltages are not set identically for | ||
The reason for this is that the DISPLAY and TRIGGER outputs are in parallel with the corresponding output from another | the three outputs. The reason for this is that the DISPLAY and TRIGGER outputs are in parallel | ||
M377, which forms a broadband termination. In contrast, the AUX SIG outputs are not combined, and therefore have | with the corresponding output from another | ||
M377, which forms a broadband termination. In contrast, the AUX SIG outputs are not combined, | |||
HF adjustment for the AUX SIG output is different than for the DISPLAY and TRIGGER outputs. | and therefore have ¼ W resistors on the PCB, shunting to ground. The ¼ W resistors become | ||
inductive at high frequencies, so the optimal HF adjustment for the AUX SIG output is different | |||
than for the DISPLAY and TRIGGER outputs. | |||
{| | {| | ||
| Line 154: | Line 157: | ||
| 3 || +15 V || | | 3 || +15 V || | ||
|- bgcolor="Yellow" | |- bgcolor="Yellow" | ||
| 4 || + | | 4 || +V<sub>in</sub> || | ||
|- bgcolor="LightGrey" | |- bgcolor="LightGrey" | ||
| 5 || Analog ground || | | 5 || Analog ground || | ||
|- bgcolor="Yellow" | |- bgcolor="Yellow" | ||
| 6 || | | 6 || −V<sub>in</in>|| | ||
|- bgcolor="LightGrey" | |- bgcolor="LightGrey" | ||
| 7 || Analog ground || | | 7 || Analog ground || | ||