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TLV6001, TLV6002, TLV6004

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SBOS779B – JUNE 2016 – REVISED OCTOBER 2016

Product Folder Links: TLV6001 TLV6002 TLV6004

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Copyright © 2016, Texas Instruments Incorporated

8.3 Feature Description

8.3.1 Operating Voltage

The TLV600x series is fully specified and tested from 1.8 V to 5.5 V (±0.9 V to ±2.75 V). Parameters that vary

with supply voltage are illustrated in the Typical Characteristics section.

8.3.2 Rail-to-Rail Input

The input common-mode voltage range of the TLV600x series extends 200 mV beyond the supply rails. This

performance is achieved with a complementary input stage: an N-channel input differential pair in parallel with a

P-channel differential pair, as shown in the Functional Block Diagram. The N-channel pair is active for input

voltages close to the positive rail, typically (V+) – 1.3 V to 200 mV above the positive supply, while the P-channel

pair is on for inputs from 200 mV below the negative supply to approximately (V+) – 1.3 V. There is a small

transition region, typically (V+) – 1.4 V to (V+) – 1.2 V, in which both pairs are on. This 200-mV transition region

may vary up to 300 mV with process variation. Thus, the transition region (both stages on) may range from

(V+) – 1.7 V to (V+) – 1.5 V on the low end, up to (V+) – 1.1 V to (V+) – 0.9 V on the high end. Within this

transition region, PSRR, CMRR, offset voltage, offset drift, and THD may be degraded compared to device

operation outside this region.

8.3.3 Rail-to-Rail Output

Designed as a micro-power, low-noise operational amplifier, the TLV600x delivers a robust output drive

capability. A class AB output stage with common-source transistors is used to achieve full rail-to-rail output swing

capability. For resistive loads up to 100 kΩ, the output swings typically to within 5 mV of either supply rail

regardless of the power-supply voltage applied. Different load conditions change the ability of the amplifier to

swing close to the rails, as shown in Figure 11.

8.3.4 Common-Mode Rejection Ratio (CMRR)

CMRR for the TLV600x is specified in several ways so the best match for a given application may be used; see

Electrical Characteristics. First, the CMRR of the device in the common-mode range below the transition region

application requires the use of one of the differential input pairs. Second, the CMRR over the entire common-

transition region, as shown in Figure 4.

8.3.5 Capacitive Load and Stability

The TLV600x is designed to be used in applications where driving a capacitive load is required. As with all op

amps, there may be specific instances where the TLV600x may become unstable. The particular op amp circuit

configuration, layout, gain, and output loading are some of the factors to consider when establishing whether or

not an amplifier is stable in operation. An op amp in the unity-gain (+1-V/V) buffer configuration that drives a

capacitive load exhibits a greater tendency to be unstable than an amplifier operated at a higher noise gain. The

capacitive load, in conjunction with the op amp output resistance, creates a pole within the feedback loop that

degrades the phase margin. The degradation of the phase margin increases as the capacitive loading increases.

When operating in the unity-gain configuration, the TLV600x remains stable with a pure capacitive load up to

sufficient to alter the phase characteristics in the feedback loop such that the amplifier remains stable. Increasing

the amplifier closed-loop gain allows the amplifier to drive increasingly larger capacitance. This increased

capability is evident when observing the overshoot response of the amplifier at higher voltage gains.