TLV9004 Op-Amp : Pin Configuration & Its Applications

The TLV900x operational amplifiers are introduced with special features like unity-gain stability, integrated EMI and RFI rejection filters, and no-phase reversal in overdrive conditions. These are mainly designed to simplify the circuit. The TLV900X series of op-amps includes TLV9001 (single-channel op-amp), TLV9002 (dual-channel op-amp), and TLV9004 (Quad-channel low-voltage op-amp). This article gives a brief description of TL9004 Op-Amp, technical features, circuit diagram, and applications.

What is TLV9004 Op-Amp?

The TLV9004 op-amp is a low-voltage operational amplifier, which comes under the family TLV900x op-amps designed by Texas Instruments. Generally, these are designed specifically with low-power, rail-to-rail output and input capabilities for portable electronic applications. The class AB output stage can drive the load less than or equal to 10 Kilo ohms loads, which are connected to any point between positive voltage (V+) and negative voltage (V-).

This common-mode input voltage range includes the input and output rails that allow the TLV900x op-amp to be used in any type of single-supply application. The TLV9004 op-amp is a low-voltage quad-channel operational amplifier with rail-to-rail input and output swing capabilities.

It is mainly utilized in space-oriented applications like wearable electronics, smoke detectors, and small electronic appliances where the high capacitive load drive and low-voltage operation are necessary. Its operating voltage range is between 1.8 Volts to 5.5 Volts.

Pin Configuration/Pin Diagram:

TLV9004 Op-amp is a 14-pin SOIC operational amplifier available in PW package, RUC package, and RTE package in 16-pin WQFN. It has four positive output voltage pins, four negative output voltage pins, one supply pin, and one ground pin. The TLV9004 op-amp pin configuration/pin diagram is illustrated below.

• Pins 1,7,8,14 -(Output voltage pins of the four operational amplifiers): OUT1 is the output voltage of channel 1, OUT2 is the output Voltage of channel 2, OUT3 is the output voltage of channel 3 and, the OUT4 output voltage of channel 4.
• Pins 2,6,9,13 – (Inverting input voltage pins of the four operational amplifiers): IN1- is inverting input voltage of channel 1, IN2- is inverting input of channel 2, IN3- is inverting input voltage of channel3 and IN4- inverting input voltage of channel 4 op-amp.
• Pins 3,5,10,12 – (Non-inverting input voltage pins of the four operational amplifiers): IN1+ is the non-inverting input voltage of channel1, IN2+ is the non-inverting input voltage of channel2, IN3+ is the non-inverting input voltage of channel 3, and IN4+ is the non-inverting input voltage of channel 4 op-amp.
• Pin4 (VDD (V+)): Positive rail or the voltage supply (High).
• Pin11 (Vss (V-)): Negative rail or the ground pin (low voltage supply).

Features & Specifications:

The TLV9004 Op-Amp specifications or technical features are given below.

• The operating voltage range of the TLV9004 op-amp is between 1.8 Volts to 5.5 Volts
• The low input offset voltage is at ±0.4 volts
• The input bias current is low, that is 5 pA
• The quiescent current is low, that is 60 microAmps
• It gives unity-gain bandwidth: 1 MHz
• The broadband noise is low, which can be 27 NV/√Hz
• The extended operating temperature range is -40°C to +125°C
• These types of Op-amps are available in several packages like 14 pin PDIP, PDSO, and GDIP.

The MCP6004 Op-Amp is an equivalent or alternative TLV9004 Op-Amp whereas LM324 and TL084 are the other equivalent quad-channel op-amps.

How to Use TLV9004 Op-Amp/Circuit Diagram:

To understand how to use the TLV9004 op-amp, a simple single-supply photodiode amplifier circuit is considered. The circuit diagram of a single-supply photodiode amplifier using TLV9002 op-amp is shown below.

To convert light energy (signals) into electrical energy (signals), photodiodes are utilized. The photon energy absorbed is proportional to the current through the photodiode, which is in the range of a few hundred picofarads to a few tens of microamps. To convert the photodiode current of low-level to a voltage signal that is used for processing in an MCU, the amplifier circuit is designed in a trans-impedance configuration.

The components required to design a single-supply photodiode amplifier circuit are given below,

• 3.3 Volts supply voltage
• 0 microamps to 10 microamps input
• 0.1 Volts to 3.2 Volts output
• 50 kHz bandwidth
• TLV9002 op-amp
• 11.5 Kilohms, 309 kiloohms, 357 ohms 10-kilo ohms resistors
• 47 pF, 10 pF capacitors.

The equation between the input current (Iin), output voltage (Vout), and the reference voltage (Vref) gives the transfer function as shown below

Vout = Iin x Rf x Vref

Where Vref = V+ (R1R2/R1+R2)

Rf = feedback resistance

To obtain the minimum output voltage, Vref is set to 100 mA by adjusting the R1 and R2 resistor values. Then the ratio is calculated as,

Vref/V+ = 0.1 V / 3.3 V = 0.0303 V

To meet this ratio, set the resistors to R1 to 11.5-kilo-ohms and R2 to 357 ohms.

Based on the input current and the desired output voltage, the required feedback resistance is calculated as below.

Rf = (Vout – Vref)/Iin = (3.2 – 0.1) / 10 microamps = 310 kV/Amps = 308-kilo ohms

Based on the feedback resistance Rf and the bandwidth -3dB, the required value of the feedback capacitor is calculated as shown below,

Cf = 1/(2π x Rf x F at -3dB)

= 1/(2π×309x 50) = 10.3 pF = 10 pF

The minimum bandwidth required by the op-amp for this circuit application depends on the Cf, Rf, and the capacitance on the input pin of the TLV9002 op-amp. The sum of shunt capacitance of the photodiode (Cpd), the common-mode input capacitance (Ccm), and the differential input capacitance (Cd) gives the value of shunt input capacitance of input capacitance (Cin) of the TLV9002, which is given below,

Cin = Cpd + Ccm + Cd = 47 pF + 5 pF + 53pF = 53 pF

The formula used to calculate the minimum bandwidth of the op-amp is given below,

F >= (Cin + Cf) / (2π x Rf x Cf^2) >= 324KHz

Hence we can conclude that the bandwidth of 1MHz of the TLV900x is used to meet the required minimum bandwidth and remains stable in this configuration. To reduce the coupling errors from the high impedance power supply and the noise signals, the bypass capacitor of 0.1 pF is connected near the power supply pins.

Where to use TLV9004 Op-Amp/Applications:

The applications of Tlv9004 op-amp are listed below

• Power Modules
• Sensor Signal Conditioning
• Motion and Smoke Detectors
• Small and Large Appliances
• Wearable Devices
• Barcode Scanners
• Personal Electronic Systems
• HVAC Systems (Heating, Ventilation and Air Conditioning systems)
• Motor Controlling Systems and
• Active Filters
• Low-side current sensing circuits

Please refer to this link to know more about TLV9004 Op-Amp Datasheet

Thus, the TLV9004 op-amps are operated between 1.8 to 5.5 volts at 40°C to 125°C temperature range with many specifications such as quiescent current, offset current, short circuit current, and offset input voltage. Here is a question for you, “What are the advantages of TLV9004 Op-Amps? “.