Core

-IN

+IN

Clamp

10 kW

10 kW

TLV333, TLV2333, TLV4333

SBOS751 – DECEMBER 2015

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Feature Description (continued)

The TLV333, TLV2333, and TLV4333 have an output stage that allows the output voltage to be pulled to its

negative supply rail, or slightly below, using the technique previously described. This technique only works with

some types of output stages. The TLV333, TLV2333, and TLV4333 are characterized to perform with this

technique; the recommended resistor value is approximately 20 k

Ω. Note that this configuration increases the

current consumption by several hundreds of microamps. Accuracy is excellent down to 0 V and as low as –2 mV.

Limiting and nonlinearity occur below –2 mV, but excellent accuracy returns when the output is again driven

above –2 mV. Lowering the resistance of the pull-down resistor allows the op amp to swing even further below

the negative rail. Resistances as low as 10 k

Ω can be used to achieve excellent accuracy down to –10 mV.

8.3.5 Input Differential Voltage

The typical input bias current of the TLV333 during normal operation is approximately 200 pA. In overdriven

conditions, the bias current can increase significantly (see Figure 17).The most common cause of an overdriven

condition occurs when the op amp is outside of the linear range of operation. When the output of the op amp is

driven to one of the supply rails, the feedback loop requirements cannot be satisfied and a differential input

voltage develops across the input pins. This differential input voltage results in activation of parasitic diodes

inside the front-end input chopping switches that combine with 10-k

Ω electromagnetic interference (EMI) filter

resistors to create the equivalent circuit shown in Figure 20. Notice that the input bias current remains within

specification within the linear region.

Figure 20. Equivalent Input Circuit

8.3.6 EMI Susceptibility and Input Filtering

Operational amplifiers vary in their susceptibility to EMI. If conducted EMI enters the operational amplifier, the dc

offset observed at the amplifier output may shift from its nominal value when EMI is present. This shift is a result

of signal rectification associated with the internal semiconductor junctions. Although all operational amplifier pin

functions can be affected by EMI, the input pins are likely to be the most susceptible. The TLV333 operational

amplifier family incorporates an internal input low-pass filter that reduces the amplifier response to EMI. Both

common-mode and differential mode filtering are provided by the input filter. The filter is designed for a cutoff

frequency of approximately 8 MHz (–3 dB), with a roll-off of 20 dB per decade.

8.4 Device Functional Modes

The TLV333 devices have a single functional mode. These devices are powered on as long as the power-supply

voltage is between 1.8 V (±0.9 V) and 5.5 V (±2.75 V).

14

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