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PZ3 Tech Notes

Noisy channel on PZ amplifier at 50kHz sampling rate


Product: PZ2, PZ3
Version: Serial numbers PZ2 < 4000, PZ3 < 2000
Date Added: 2012-08-03


In some cases, user may see low amplitude high frequency noise on the 15th channel of a PZ2 amplifier board (8th channel of a PZ3 board) when running at 50kHz sampling rate.


It is recommended that users who are operating at 50kHz contact TDT to request an RMA.

Building a custom headstage to use with PZ, IZ, or ACO


Product: PZ5, PZ2, PZ3, IZ2, IZ2H, IZ2M, IZ2MH, ACO32, ACO64
Version: All
Date Added: 2012-02-08


This tech note provides the information needed to wire a custom or third-party headstage to TDT amplifiers, stimulus isolators, and commutators.


The PZ5, PZ2, PZ3, IZ2, IZ2H, IZ2M, IZ2MH, ACO32, and ACO64 all use the same female mini-DB26 connectors. The mating male connector is made by TE Connectivity (previously Tyco), part number 5749621-2, and can be purchased from Newark, Digikey, or similar vendors. The part number for the connector's backshell kit is 749608-2.

The PZ5, PZ2, PZ3, IZ2, and IZ2H are all battery powered. To conserve power, each bank of channels will not turn on unless a headstage is connected. The device detects whether a headstage is connected through the HSD (HeadStage Detect) pins: pins 18 and 19. These pins should be shorted together on the headstage connector. If pins 18 and 19 are not shorted the headstage will not be detected and the bank that it is connected to will power off.


This does not apply to the IZ2M and IZ2MH. In those devices all banks are always powered.

The pins on the headstage should be made to match the connector on the intended device. The pinouts for each device are shown below.


The user must increment the channel numbers by 16 (or 8) according to the amp, mode and position of the connector. So, for the connector labeled 'A', A1 is channel 1 while on the connector labeled 'B', A1 may be channel 17.

PZ5 Connector Pinout for Building Headstages

PZ5 NeuroDigitizers have up to eight 26-pin headstage connectors on the back of the unit. The connectors are labeled alphabetically from bottom to top. Each connector carries signal for one bank of channels with ground and reference. The corresponding channel numbers depend on:

  1. the reference mode configurations

  2. the position of the bank in a logical amplifier.

For simplicity sake, the diagrams below assume channels for that connector begin with channel 1. For example, A1 - A16 represent the 16 channels coming from the connected headstage.

Local Mode

None Mode

Shared Mode

Differential Mode

PZ2 Connector Pinout for Building Headstages

PZ3 Connector Pinout for Building Headstages

IZ2, IZ2M, IZ2MH Connector Pinout for Building Headstages

IZ2H Connector Pinout for Building Headstages

The ACO passes signals from each header to the pins on the associated DB26 connector on the face of the commutator. The unused pins should not be connected. The pins on the headstage should be made to map to the connected amplifier/stimulator via the header as follows:

ACO Headers - Pinout for Building Active Headstages

For PZ2 or PZ5

For PZ3

ACO Headers - Pinout for Building Passive Headstages

For IZ2, IZ2M, or IZ2MH

For IZ2H

PZ2/PZ3 Signal inversion


Product: PZ2, PZ3
Version: PZ2-32:1006-1010, PZ2-64:2018-2025, PZ2-128:2020-2026, PZ2-256:2009-2010, PZ3 < 2000
Date Added: 2009-12-07


PZ2s and PZ3s with the above serial numbers will generate inverted signal outputs.


Place an MCScale component with a SF of '-1' into your circuit to invert the data like the example shown below.


If you experience this issue contact TDT and request an RMA.

PZ3_ChanMap macro causes a warning in RPvdsEx


Product: PZ3, RPvdsEx
Version: All
Date Added: 2009-04-09


When using the PZ3_ChanMap macro in RPvdsEx, the macro causes a warning message to be displayed even when used correctly. The warning message occurs when RPvdsEx detects a channel number mismatch between the RZ2_Input_MC macro and the PZ3_ChanMap macro.


The RZ2_Input_MC macro is designed for the PZ2 preamplifier which contains 16 recording channels per bank. The PZ3 amplifier differs in that each bank contains 8 channels for recording and 8 channels for impedance testing. The number of channels parameter defined in the PZ3_ChanMap macro should be configured to output the number of recording channels according to the PZ3. This means that the RZ2_Input_MC macro will have double the number of channels compared to the PZ3_ChanMap macro.

For example, when using a 32-channel PZ3, the PZ3_ChanMap macro channel number parameter would be set to 32 while the RZ2_Input_MC macro channel number would need to be set to 64 (since the PZ3 has half the number of recording channels per bank compared to the PZ2). Refer to the images below for examples of how to correctly use the PZ3_ChanMap macro.



Ensure that the correct number of channels is set before attempting to use the circuit.