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VIN+

VIN−

R1

R1

R3

THS1230

AIN+

REFT

REFB

AIN−

R2

R2

VBIAS

VBIAS

V IN

AVDD

2

THS1230

AIN+

AIN−

REFT

REFB

Digital Outputs

THS1230

SLAS291B – OCTOBER 2000 – REVISED MARCH 2004

Figure 18. DC-Coupled Differential Input Circuit

A single-ended source may give better overall system performance when it is converted to a differential signal

before driving the THS1230. The configuration in Figure 19 takes a VIN of 1 V and drives the 1:1 transformer

ratio so that value of AIN+ and AIN– converts to fullscale value at the ADC digital output. With VIN at –1 V the

value at AIN+ and AIN– converts to 0 at the ADC digital outputs.

Figure 19. Transformer Coupled Single-Ended Input

The output of THS1230 is in unsigned binary code. The ADC input over-range indicator is output on pin OVRNG.

Capacitive loading on the output should be kept as low as possible (a maximum loading of 10 pF is

recommended) to ensure best performance. Higher output loading causes higher dynamic output currents and

can therefore increase noise coupling into the part's analog front end. To drive higher loads the use of an output

buffer is recommended.

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