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Product(s)

- Obsolete

Product(s)

TSA1002

15/20

Figure 6 : Input dynamic range for the various configurations

The applications requiring single-ended inputs

can be configured like reported on Figure 7 for an

AC-coupled input or on Figure 8 and 9 for a

DC-coupled input.

In the case of AC-coupled analog input, the

analog inputs Vin and Vinb are biased to the same

voltage that is the common mode voltage of the

circuit (INCM). The INCM and reference voltages

may remain at their internal level but can also be

fixed externally.

Figure 7 : AC-coupled Single-ended input

In the case of DC-coupled analog input with 1V

DC signal, the DC component of the analog input

set the common mode voltage. As an example fig-

ure 8, INCM is set to the 1V DC analog input while

VREFM is connected to ground and VREFP let in-

ternal; we achieve a 2Vpp differential amplitude.

Figure 9 describes a configuration for a 1Vpp

analog signal with a 0.5V DC input. In this case,

while VREFP is kept internally at 1V, VREFM is

connected to VINB and INCM externally to 0.5V;

the dynamic is then 1Vpp (VREFP-VREFM=0.5V).

Figure 8 : DC-coupled 2Vpp analog input

Figure 9 : DC-coupled 1Vpp analog input

Dynamic characteristics, while not being as

remarkable as for differential configuration, are

still of very good quality. Measurements done at

50Msps, 2MHz input frequency, -1dBFS input

level sum up these performances. An SFDR of

-64.5dBc, a SNR of 57.8dB and an ENOB Full

Scale of 9.3bits are achieved.

INCM

+FS: code 1023

VIN

VINB

0: code 511

-FS: code 0

Differential configuration

Single-ended configuration:

balanced inputs

Single-ended configuration:

unbalanced inputs

INCM

+FS: code 1023

-FS: code 0

0: code 511

INCM

VIN

+FS + offset: code > 1023

-FS + offset: code > 0

VIN

VINB

INCM

VIN

VINB

INCM

VIN

VINB

INCM

VIN

Wrong configuration!

Ao + ac

Ao + ac

Ao

Ao + ac

Ao

Ao

Ao + ac

VIN - VINB

VIN - VINB

VIN - VINB

VINB

50

Ω

10nF

Signal source

TSA1002

VIN

VINB

INCM

33pF

100k

Ω

100k

Ω

common

mode

TSA1002

VIN

VINB

INCM

330pF

4.7uF

10nF

Analog

DC

AC+DC

VREFP

VREFM

VREFP-VREFM = 1 V

330pF

4.7uF

10nF

Analog

DC

AC+DC

TSA1002

VIN

VINB

INCM

VREFM

VREFP-VREFM = 0.5 V

0.5V power supply