Which TDS600 models support standard 1 MΩ input impedance?

Only the TDS644A and TDS684B support selectable 1 MΩ and 50 Ω input impedance. The other models in this family, such as the TDS640, TDS640A, TDS644B, TDS684A, TDS684C, TDS620A, and TDS620B, are dedicated 50 Ω input instruments.

What is the maximum acquisition record length for the TDS600 series models?

The record length varies by model generation. For example, the TDS644A has a standard record length of 2K points per channel, while the TDS644B, TDS684B, and TDS620B feature a larger standard record length of 15,000 points.

Are there 2-channel options available in the TDS600 series?

Yes, the TDS620A and TDS620B are the 2-channel instruments within this series, both offering a 500 MHz analog bandwidth.

Tektronix TDS600 Series Oscilloscopes

10 models with full specifications from Tektronix.

The Tektronix TDS600 Series consists of high-speed digital storage and real-time oscilloscopes engineered for demanding digital design, verification, and debugging applications. This series covers a broad range of capabilities, offering analog bandwidths from 500 MHz up to 3 GHz, and real-time sample rates starting at 2 GS/s and reaching up to 10 GS/s. Built with an 8-bit vertical resolution platform that can be extended with signal averaging, these instruments are designed for engineers requiring fast rise times and simultaneous multi-channel acquisition. This guide assists technical buyers and engineers in comparing models within the TDS600 family to determine the correct configuration of channels, bandwidth, input impedance, and display technology for their specific testing needs.

Bandwidth Range: 500 MHz to 3 GHz
Max Real-Time Sample Rate: 2 GS/s to 10 GS/s
Channel Options: 2 or 4 analog channels
Vertical Resolution: 8-bit (expandable with averaging)

Models in this series

Model	Type	Display	Input Coupling	Input Impedance
TDS694C	DSO	7-inch (178 mm) color NuColor liquid crystal shutter display (640 × 480)	—	—
TDS684B	Digital	—	AC, DC, GND	1 MΩ ±1% \|\| 10 pF ±2 pF, or 50 Ω ±1%
TDS644A	*misc	Color display	AC, DC, GND	1 MΩ or 50 Ω
TDS640A	Digital	7-inch monochrome CRT, 640 x 480 pixels	DC, GND	50 Ω
TDS644B	*misc	Color VGA display	DC, GND	50 Ω
TDS684C	DSO	7-inch color liquid crystal shutter CRT	DC, GND	50 Ω
TDS620A	Digital	17.78 cm (7 in) Monochrome CRT	DC, GND	50 Ω
TDS620B	Digital	Monochrome CRT Display	DC, GND	50 Ω
TDS640	Digital	7-inch monochrome CRT	DC or GND	50 ̩
TDS684A	*misc	7-inch Color CRT (NuColor liquid crystal shutter display)	DC, GND	50 Ω

Bandwidth and Sampling Rate Categorization

The TDS600 series models are categorized primarily by their analog bandwidth and real-time sampling rates:

3 GHz Performance: The TDS694C serves as the highest-performance model in the family, providing a 3 GHz bandwidth and a 10 GS/s real-time sample rate simultaneously across all 4 channels, with a calculated rise time of 120 ps.
1 GHz Performance: The TDS684A, TDS684B, and TDS684C provide a 1 GHz bandwidth with 5 GS/s real-time sampling. Calculated rise times are 350 ps for the TDS684A and under 350 ps for the TDS684C.
500 MHz Performance: The TDS640, TDS640A, TDS644A, TDS644B, TDS620A, and TDS620B operate with a 500 MHz analog bandwidth. Sampling rates for these units range from 2 GS/s (TDS640, TDS640A, TDS644A, TDS620A) to 2.5 GS/s (TDS644B, TDS620B).

Channel Configurations and Display Types

Depending on the physical layout of your device under test, you can select between 2-channel and 4-channel options, as well as monochrome or color displays:

2-Channel Models: The TDS620A and TDS620B offer dual-channel configurations, utilizing a 7-inch monochrome CRT display.
4-Channel Monochrome Models: The TDS640 and TDS640A provide 4 channels with a 7-inch monochrome CRT display, designed for multi-channel testing where color differentiation is not required.
4-Channel Color Models: The TDS644A, TDS644B, TDS684A, TDS684C, and TDS694C feature color displays (such as VGA or NuColor liquid crystal shutter systems) to help distinguish overlapping waveforms.

Input Impedance and Signal Integrity

Input impedance varies across the series, affecting how the instruments interface with external circuitry:

Dedicated 50 Ω Inputs: The TDS640, TDS640A, TDS644B, TDS684A, TDS684C, TDS620A, and TDS620B are dedicated 50 Ω systems. This design optimizes high-frequency signal transfer and minimizes reflections.
Selectable 1 MΩ / 50 Ω Inputs: The TDS644A and TDS684B provide selectable input coupling and impedance (1 MΩ or 50 Ω), offering greater compatibility with high-impedance passive probes alongside direct 50 Ω RF cables.

Frequently asked questions

Which TDS600 models support standard 1 MΩ input impedance?: Only the TDS644A and TDS684B support selectable 1 MΩ and 50 Ω input impedance. The other models in this family, such as the TDS640, TDS640A, TDS644B, TDS684A, TDS684C, TDS620A, and TDS620B, are dedicated 50 Ω input instruments.
What is the maximum acquisition record length for the TDS600 series models?: The record length varies by model generation. For example, the TDS644A has a standard record length of 2K points per channel, while the TDS644B, TDS684B, and TDS620B feature a larger standard record length of 15,000 points.
Are there 2-channel options available in the TDS600 series?: Yes, the TDS620A and TDS620B are the 2-channel instruments within this series, both offering a 500 MHz analog bandwidth.