Overview
The LM3485MMX is a high-efficiency PFET buck controller from Texas Instruments. It is designed to facilitate the development of small, low-cost, switching buck regulators for a wide range of applications. The hysteretic control architecture of the LM3485MMX simplifies the design process by eliminating the need for control-loop compensation. This controller operates over a wide input voltage range of 4.5 V to 35 V and can adjust the output voltage from 1.242 V to VIN, making it versatile for various power management needs.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| Input Voltage Range | 4.5 | - | 35 | V |
| Output Voltage Range | 1.242 | - | VIN | V |
| Operating Junction Temperature | -40 | - | 125 | °C |
| Maximum Operating Frequency | - | - | > 1 MHz | - |
| Quiescent Current at Ground Pin | 250 | 400 | - | µA |
| Feedback Voltage | 1.217 | 1.242 | 1.267 | V |
| Comparator Hysteresis | 10 | 15 | 20 | mV |
| Current Limit Comparator Trip Voltage | 110 | - | 880 | mV |
| Package | - | - | VSSOP-8 | - |
Key Features
- Easy-to-use hysteretic control methodology without the need for control-loop compensation.
- No external sense resistor required for current limit protection.
- High efficiency operation with up to 93% efficiency.
- 100% duty cycle operation for ultralow dropout.
- Adjustable output voltage using two external resistors.
- Operating frequency reduces at light loads for excellent efficiency.
- Feed-forward capacitor (Cff) for reducing output ripple and increasing operating frequency.
Applications
- Set-Top Box
- DSL or Cable Modem
- PC/IA
- Auto PC Device
- TFT Monitor
- Battery-Powered Portable Applications
- Distributed Power Systems
Q & A
- What is the input voltage range of the LM3485MMX? The input voltage range is from 4.5 V to 35 V.
- How is the output voltage adjusted? The output voltage can be adjusted using two external resistors.
- What is the typical efficiency of the LM3485MMX? The typical efficiency is up to 93%.
- Does the LM3485MMX require an external sense resistor for current limit protection? No, it does not require an external sense resistor.
- What is the maximum operating frequency of the LM3485MMX? The maximum operating frequency is greater than 1 MHz.
- What is the package type of the LM3485MMX? The package type is VSSOP-8.
- What are some common applications of the LM3485MMX? Common applications include set-top boxes, DSL or cable modems, PC/IA devices, auto PC devices, TFT monitors, battery-powered portable applications, and distributed power systems.
- How does the hysteretic control architecture benefit the design process? The hysteretic control architecture simplifies the design by eliminating the need for control-loop compensation.
- What is the role of the feed-forward capacitor (Cff) in the LM3485MMX? The feed-forward capacitor reduces output ripple and increases the operating frequency.
- What is the operating junction temperature range of the LM3485MMX? The operating junction temperature range is from -40°C to 125°C.
