Overview
The LM2577T-ADJ, produced by Texas Instruments, is a monolithic integrated circuit designed to provide all the power and control functions for step-up (boost), flyback, and forward converter switching regulators. This device is part of the SIMPLE SWITCHER® series and is known for its simplicity and low component count. It is available in various output voltage versions, including fixed outputs of 12V and 15V, as well as an adjustable output version. The LM2577T-ADJ features a 3.0A NPN switch and includes protection circuitry such as current and thermal limiting, and undervoltage lockout, making it a reliable choice for a wide range of applications.
Key Specifications
| Parameter | Conditions | Typical | Limit |
|---|---|---|---|
| Input Voltage Range | 3.5V to 40V | - | - |
| Output Voltage Range | 1.23V to 15V (adjustable) | - | - |
| Output Switch Current | - | 3.0A | 3.7A (min), 5.3A (max) |
| Switch Saturation Voltage | ISWITCH = 2.0A | 0.5V | 0.7V (max) |
| Maximum Duty Cycle | VCOMP = 1.5V | 95% | 93% (min) |
| Switching Frequency | - | 52 kHz | - |
| Operating Temperature Range | - | -40°C to 125°C | - |
| Thermal Resistance (Junction to Ambient) | K Package | - | 35°C/W |
Key Features
- Requires few external components, making it cost-effective and simple to use.
- NPN output switches capable of handling 3.0A and standing off 65V.
- Wide input voltage range: 3.5V to 40V.
- Current-mode operation for improved transient response, line regulation, and current limit.
- 52 kHz internal oscillator requiring no external components.
- Soft-start function to reduce in-rush current during start-up.
- Output switch protected by current limiting and thermal limiting.
- Undervoltage lockout for added protection.
Applications
The LM2577T-ADJ is versatile and can be used in a variety of applications, including:
- Step-up (boost) converters.
- Flyback converters.
- Forward converters.
- Power supplies for industrial and consumer electronics.
- Battery-powered systems requiring voltage regulation.
- Automotive and aerospace systems where robust voltage regulation is necessary.
Q & A
- What is the input voltage range of the LM2577T-ADJ?
The input voltage range is from 3.5V to 40V. - What are the available output voltage versions for the LM2577T-ADJ?
The device is available in fixed output versions of 12V and 15V, as well as an adjustable output version. - What is the maximum output switch current of the LM2577T-ADJ?
The maximum output switch current is 3.0A, with a minimum limit of 3.7A and a maximum limit of 5.3A. - What is the switching frequency of the LM2577T-ADJ?
The switching frequency is fixed at 52 kHz. - What is the operating temperature range of the LM2577T-ADJ?
The operating temperature range is from -40°C to 125°C. - Does the LM2577T-ADJ have built-in protection features?
Yes, it includes current limiting, thermal limiting, and undervoltage lockout. - What is the purpose of the soft-start function in the LM2577T-ADJ?
The soft-start function reduces in-rush current during start-up. - Is the LM2577T-ADJ suitable for high-temperature environments?
Yes, it has a maximum junction temperature of 125°C. - Can the LM2577T-ADJ be used in automotive applications?
Yes, it is suitable for automotive and aerospace systems where robust voltage regulation is necessary. - Is the LM2577T-ADJ still in production?
No, the LM2577T-ADJ is obsolete and no longer manufactured, but substitutes are available.
