11A32: Difference between revisions

Revision as of 16:27, 29 December 2022

Tektronix 11A32
400 MHz dual channel vertical plug-in Tektronix 11A32 Compatible with 11000-series scopes Produced from 1987 to (?) Manuals 11A32 manual (PDF) 11A32 Service Reference (PDF) 11A32 Extended Service Manual (PDF, OCR, with schematics) Tektronix 11k Plug-in NVRAM Replacement (PDF) Tektronix 11A32 Preliminary Service Manual (PDF) (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix 11A32 is a 400 MHz dual-channel amplifier plug-in for 11000-series scopes. Each of the attenuator modules contains an M474 buffer amplifier. Each of the attenuator modules feeds an M377 amplifier IC. The output signals of the two M377s combine at the output of the 11A32. The fine steps between the deflection ranges are calibrated in 1% increments.

The 11A32 and the 11A34 use exactly the same firmware.

Each of the 11A32’s two channels has its own M377 amplifier. The display outputs of the two amplifiers are hard wired in parallel and drive the mainframe’s 50 Ω input impedance. The same is true of the trigger outputs of the two amplifiers. The version of the M377 used in the 11A32 has 100 Ω output impedance so that two of them in parallel create a source impedance of 50 Ω.

Each M377 amplifier's nominal common-mode output voltage is zero whether enabled or not.

When not enabled each M377 differential output is exactly zero by design. This fact is used during calibration by the plugin’s firmware to determine the mainframe’s imbalance and compensate for it during normal operation. See the block diagram below.

Key Specifications

Bandwidth	DC to 400 MHz plus 100 MHz and 20 MHz BWL filters
Rise time	875 ps in 1 GHz mainframe such as the 11402, 11402A, 11403, 11403A, DSA601A, or DSA602A
Deflection	1 mV to 10 V per division in 1% calibrated steps
Input impedance	50 Ω or 1 MΩ
Features	High-Resolution Calibrated DC Offset Fast Overdrive Recovery 50 Ω mode: 5 V RMS overload protected with manual reset

Internals

The 11A32 and 11A34 were originally intended to use Intel 8052 microcontrollers. However, during development, the firmware swelled beyond that chip's 8192-byte maximum on-chip ROM size. Doug Haines found an alternate supplier of 8051-compatible chips (OKI Semiconductor) that offered a 16Kbyte on-chip ROM, and that's what the plug-ins wound up with. The finished code size wound up at about 14 KB.

The 11A32 also contains a DS1120 NVRAM and an ACVS sample and hold module.

Links

Pictures

Block diagram
11A32 Main Board Schematic
11A32 Main Interface
left side internal
right side internal

Custom ICs used in the 11A32

Page	Model	Part nos	Description	Designers	Used in
M377	M377	165-2129-03 • 165-2089-06 • 155-2089-05	amplifier	John Addis	11A16 • 11A32 • 11A33 • 11A34 • 11A52 • 2245 • 2245A • 2247 • 2247A • 2252 • TDS410 • TDS420 • TDS460 • TDS520D • TDS540D • TDS580D • TDS680C • TDS684C • TDS714L • TDS724D • TDS754D • TDS784D
M474	M474		amplifier	John Addis • Ivan John Cousins	11A32 • 11A34

@@ Line 22: / Line 22: @@
 The fine steps between the deflection ranges are calibrated in 1% increments.
-The 11A32 uses the same firmware as the [[11A34]].
+The 11A32 and the [[11A34]] use exactly the same firmware.
-The display output of the channel 1 M377 amplifier (A1U310) is in parallel with the display output of the channel 2 M377 amplifier (A1U410)
+Each of the 11A32’s two channels has its own M377 amplifier.
-and the combined signal is presented to the mainframe via the plug-in interface connector.
+The display outputs of the two amplifiers are hard wired in parallel and drive the mainframe’s 50 Ω input impedance.
-The same is true of the trigger outputs of both amplifiers.
+The same is true of the trigger outputs of the two amplifiers.
-This is possible because regardless of whether the amplifier's output is enabled:
+The version of the M377 used in the 11A32 has 100 Ω output impedance so that two of them in parallel create a source impedance of 50 Ω.
-* each amplifier's output has a source impedance of 100 Ω so the two amplifiers in parallel match the 50 Ω spec of the [[11000 Series plug-in interface]].
-* each amplifier's nominal common-mode output voltage is zero
+Each M377 amplifier's nominal common-mode output voltage is zero whether enabled or not.
-* each amplifier's nominal differential output voltage is zero
+When not enabled each M377 differential output is exactly zero by design.
+This fact is used during calibration by the plugin’s firmware to determine the mainframe’s imbalance and compensate for it during normal operation.
 See the block diagram below.