What TPS7A11 Is :Low Dropout Voltage Regulator

Many of the portable devices we use today are battery-powered. Voltage regulators play a crucial role in these devices. The increased demand for voltage regulators in very sensitive applications requiring very low voltages has led to a rise in the need for LDO ICs. Low Dropout voltage regulators can regulate small voltages in the mV range. They typically operate with an input voltage of 200mV to 500mV. An efficient, compact power supply solution for portable electronics is needed, with low input and low output requirements. One of the LDOs with these characteristics is TPS7A11 Low Dropout Voltage Regulator.

 

What is TPS7A11 IC?

 

TPS7A11 is a low dropout voltage regulator. It is available as an ultra-small, low quiescent current IC. This IC can be connected to a power supply as low as 140 mV above the output voltage.

 

By using the VBIAS rail, which powers the device's internal circuitry, TPS7A11 can support very low input voltages. These features make TPS7A11 an ideal choice for battery-powered applications.

 

Block Diagram

Excellent Transient Response

 

Due to the device's high input impedance and low output impedance, TPS7A11 responds quickly to transients on the input supply and output current.

 

This feature also provides the device with a high power supply rejection ratio and a low internal noise floor. TPS7A11 exhibits excellent load and line transients.

 

Global Undervoltage Lockout

 

This IC has two undervoltage lockout circuits, one on the BIAS pin and the other on the IN pin. These circuits prevent TPS7A11 from turning on until both the BIAS and IN voltages rise above their respective lockout voltages.

 

These two UVLO signals are internally connected through an AND gate. Therefore, if either signal is below the lockout voltage, the device will turn off.

 

Active Discharge

 

To actively discharge the output voltage, the active discharge option employs an internal pulldown MOSFET. This MOSFET connects a 120Ω resistor to the ground when the device is disabled. The circuit activates when the enable pin is low or when the device is in thermal shutdown mode.

 

Internal Foldback Current Limit

 

This circuit protects TPS7A11 from high-load current faults or voltage shorting events.

 

Thermal Shutdown

 

When the thermal junction temperature of the device rises to the thermal shutdown temperature, this circuit disables the device. Once the temperature falls below the shutdown threshold, thermal shutdown hysteresis ensures that the LDO resets.

 

TPS7A11 operates in three functional modes: Normal operation, Dropout operation, and Disabled mode. In Dropout mode, the device is not in regulation, and the output voltage is equal to the input voltage minus the voltage drop across the pass element of the device. In Disabled mode, the device is turned off.

 

Circuit Diagram

 

Based on application requirements, external components are necessary alongside the TPS7A11 IC.

Capacitor Types

 

TPS7A11 requires capacitors at the input, output, and bias pins for stability. Ceramic capacitors are mostly recommended, and multilayer ceramic capacitors should be used with care.

 

Input-Output Capacitor Requirements

 

The minimum input capacitor required for TPS7A11 is 2.2 µF. The minimum value for the output capacitor is 2.2 µF, and the maximum value is 22 µF. The value of the bias capacitor should be 0.1 µF.

 

Pin Configuration of TPS7A11

 

TPS7A11 is available in a 2.00 mm x 2.00 mm WSON, 6-pin DRV package, and an ultra-small 0.74 mm x 1.09 mm, 5-pin DSBGA (YKA) package.

DRV Package of TPS7A11 Low Dropout Voltage Regulator

 

 

For this package, it is recommended to connect the thermal pad to ground.

 

1. Pin 1 is the regulated output pin OUT. For stability, a capacitor is required to be connected from OUT to ground. Ceramic capacitors are used for good transient values and should be placed close to the output pin of the device.
2. Pin 2 is the NC pin, which is not connected internally. This pin can be left floating or connected to ground for good thermal dissipation.
3. Pin 3 is the enable pin EN. To enable the device, this pin is raised high, and making the pin low disables the device. If enable functionality is not required, this pin can be connected to the IN or BIAS pin, provided the voltage at the IN pin is greater than 0.9V.
4. Pin 4 is the bias pin BIAS. This pin allows for low-input voltage and low-output voltage conditions. For best performance, a capacitor should be connected from this pin to ground.
5. Pin 5 is the ground pin GND.
6. Pin 6 is the input pin IN. For stability, a capacitor should be connected from this input pin to ground, placed close to the IN pin.

 

5-Pin DSBGA – YKA Package

 

For this package, the functioning of the pins is the same as the DRV package.

 

• A1 is the input pin IN.
• A3 is the output pin OUT.
• B2 is the ground pin GND.
• C1 is the bias pin BIAS.
• C3 is the enable pin EN.

 

Specifications of TPS7A11

 

Specifications of TPS7A11 are as follows:

 

• TPS7A11 has an ultra-low voltage range from 0.75V to 3.3V.
• This IC is available in DRV and YKA packages.
• For the DRV package at 500mA, the ultra-low dropout for minimum power loss is 140mV.
• For the YKA package, the ultra-low dropout is 110mV.
• Low quiescent current for VIN is 1.6 µA.
• For VBIAS, IQ is 6 µA.
• Load, line, and temperature have 1.5% accuracy.
• This IC has a high PSRR of 64dB at 1 kHz.
• TPS7A11 has an active output discharge.
• This voltage regulator is available for fixed voltages ranging from 0.5V to 3V.
• The range for VBIAS is from 1.7V to 5.5V.
• The recommended operating junction temperature of TPS7A11 is from -40°C to 125°C.
• Output voltage drawn from this IC at the operating junction temperature conditions ranges from a minimum of 0.5V to a maximum of 3V.
• A bias capacitor of 0.1 µF is used along with the IC.
• Maximum ESR must be lower than 250mΩ when operating at junction temperature conditions.

 

Applications of TPS7A11 Low Dropout Voltage Regulator

 

Applications of TPS7A11 voltage regulator are as follows:

 

• These are used to supply power to the lower core voltages of modern microcontrollers and sensors.
• These are used in smartwatches and fitness trackers.
• Wireless headphones and earbuds also make use of this voltage regulator.
• This voltage regulator can be found in camera modules.
• Portable medical devices, smartphones, tablets, and solid-state devices make use of the TPS7A11 voltage regulator.

 

Alternative IC

 

The IC that can be used as an alternative to TPS7A11 is TPS7A26.

 

Because of its low input voltage and low output voltage requirements, TPS7A11 has become an ideal choice for battery-powered, noise-sensitive portable electronics. Although traditional LDOs have lower input and low output characteristics, their efficiency is low.

 

TPS7A11 uses a bias rail to operate at lower input voltages, thereby reducing the power dissipation across the die. Further specifications of this voltage regulator can be found in the datasheet from Texas Instruments. For which of your applications was TPS7A11 useful? What capacitor values did you use in the circuit?