company blog about TI LM27761DSGR Low-Noise Regulated Inverter With Integrated LDO

TI LM27761DSGR Low-Noise Regulated Inverter With Integrated LDO

In modern electronic devices, the performance of the power management chip directly affects the stability and efficiency of the device.TI LM27761DSGR is a low noise regulated inverter with integrated LDO, which is ideal for many electronic products due to its high efficiency, low noise and compact design. Shenzhen Mingjiada Electronics Co., Ltd. provides customers with original and genuine LM27761DSGR to ensure the high performance and reliability of the product.

Product Description Of LM27761DSGR
LM27761DSGR low-noise regulated switched-capacitor voltage inverter delivers a very low-noise adjustable output for an input voltage in the range of 2.7 V to 5.5 V. Four low-cost capacitors are used in the application solution to provide up to 250 mA of output current. The regulated output for the device is adjustable between −1.5 V and −5 V. The LM27761DSGR operates at 2-MHz (typical) switching frequency to reduce output resistance and voltage ripple. With an operating current of only 370 µA (charge-pump power efficiency greater than 80% with most loads) and 7-µA typical shutdown current, the LM27761DSGR provides ideal performance when driving power amplifiers, DAC bias rails, and other high-current, low-noise voltage applications.

Specifications Of LM27761DSGR
Output Voltage:- 5 V to - 1.5 V
Output Current:250 mA
Number of Outputs:1 Output
Input Voltage - Min:2.7 V
Input Voltage - Max:5.5 V
Quiescent Current:100 uA
Switching Frequency:2 MHz
Minimum Operating Temperature:- 40 C
Maximum Operating Temperature:+ 85 C
Input Voltage:2.7 V to 5.5 V
Load Regulation:4.6 uV/mA
Operating Supply Current:370 uA
Supply Voltage - Min:2.7 V
Unit Weight:11 mg

Feature Description Of LM27761DSGR
Undervoltage Lockout
The LM27761DSGR has an internal comparator that monitors the voltage at VIN and forces the device into shutdown if the input voltage drops to 2.4 V. If the input voltage rises above 2.6 V, the LM27761DSGR resumes normal operation.

Input Current Limit
The LM27761DSGR contains current limit circuitry that protects the device in the event of excessive input current and/or output shorts to ground. The input current is limited to 500 mA (typical) when the output is shorted directly to ground. When the LM27761DSGR is current limiting, power dissipation in the device is likely to be quite high. In this event, thermal cycling is expected.

PFM Operation
To minimize quiescent current during light load operation, the LM27761DSGR allows PFM or pulse-skipping operation. By allowing the charge pump to switch less when the output current is low, the quiescent current drawn from the power source is minimized. The frequency of pulsed operation is not limited and can drop into the sub-2-kHz range when unloaded. As the load increases, the frequency of pulsing increases until it transitions to constant frequency. The fundamental switching frequency in the LM27761DSGR is 2 MHz.

Output Discharge
In shutdown, the LM27761DSGR actively pulls down on the output of the device until the output voltage reaches GND. In this mode, the current drawn from the output is approximately 1.85 mA.

Thermal Shutdown
The LM27761DSGR implements a thermal shutdown mechanism to protect the device from damage due to overheating. When the junction temperature rises to 150°C (typical), the device switches into shutdown mode.
The LM27761DSGR releases thermal shutdown when the junction temperature is reduced to 130°C (typical).

Application Information Of LM27761DSGR
The LM27761DSGR low-noise charge pump voltage converter inverts a positive voltage in the range of2.7 V to 5.5 V to a negative output voltage configurable with external gain setting resistors. The device uses four low-cost capacitors to provide up to 250 mA of output current. The LM27761DSGR operates at a 2-MHz oscillator frequency to reduce charge-pump output resistance and voltage ripple under heavy loads. With an operating current of only 370 μA and 7-μA typical shutdown current, the LM27761DSGR provides ideal performance for battery-powered systems.

Applications Of LM27761DSGR
Operational Amplifier Power
Wireless Communication Systems
Cellular-Phone Power-Amplifier Biasing
Interface Power Supplies
Handheld Instrumentation
Hi-Fi Headphone Amplifiers
Powering Data Converters

Functional Block Diagram

Voltage Inverting Principle