Overview
The LTC4121IUD#TRPBF, produced by Analog Devices Inc., is a high-performance 400mA constant-current/constant-voltage (CC/CV) synchronous step-down battery charger. This device is designed to handle a wide range of battery charging requirements, including accurate RUN pin threshold, low voltage battery preconditioning, bad battery fault detection, timer termination, auto-recharge, and NTC temperature qualified charging. The LTC4121 series is available in various configurations, including the LTC4121 and LTC4121-4.2, each tailored to specific battery voltage ranges.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Operating Input Supply Range | 4.4 | 40 | V | ||
| Battery Voltage Range (LTC4121) | 0 | 18 | V | ||
| Battery Voltage Range (LTC4121-4.2) | 0 | 4.2 | V | ||
| DC Supply Current (Switching) | FREQ = GND | 3.5 | mA | ||
| DC Supply Current (Standby Mode) | 142 | 260 | µA | ||
| DC Supply Current (Sleep Mode) | 60 | µA | |||
| DC Supply Current (Shutdown Mode) | 1 | µA | |||
| Feedback Pin Regulation Voltage (LTC4121) | 2.393 | 2.400 | 2.407 | V | |
| Regulated Float Voltage (LTC4121-4.2) | 4.188 | 4.200 | 4.212 | V | |
| Battery Charge Current (RPROG = 3.01k) | 383 | 402 | 421 | mA | |
| Battery Charge Current (RPROG = 24.3k) | 45 | 50 | 55 | mA | |
| Minimum Controllable On-Time | 120 | ns | |||
| Duty Cycle Maximum | 94 | % | |||
| Top Switch RDSON | ISW = –100mA | 0.8 | Ω | ||
| Bottom Switch RDSON | ISW = 100mA | 0.5 | Ω | ||
| Peak Inductor Current Limit | Measured Across RSNS with a 15µH Inductor in Series with RSNS | 585 | 1050 | 1250 | mA |
| Switch Pin Current (IN Open-Circuit, VBAT = VSW = 4.2V) | 7 | 15 | µA |
Key Features
- Accurate RUN Pin Threshold: Ensures precise control over the charging process.
- Low Voltage Battery Preconditioning: Handles low voltage batteries effectively.
- Bad Battery Fault Detection: Automatically detects and handles faulty batteries.
- Timer Termination and Auto-Recharge: Supports timer-based charging and automatic recharge functions.
- NTC Temperature Qualified Charging: Ensures safe charging across a range of temperatures using NTC thermistors.
- High Efficiency Synchronous Step-Down Charging: Optimizes charging efficiency with synchronous step-down architecture.
- Wide Operating Temperature Range: Guaranteed performance from –40°C to 125°C.
Applications
- Portable Electronics: Ideal for charging batteries in smartphones, tablets, and other portable devices.
- Industrial Battery Systems: Suitable for industrial battery management systems requiring precise and reliable charging.
- Automotive Systems: Can be used in automotive applications where robust and efficient battery charging is necessary.
- Medical Devices: Applicable in medical devices that require reliable and safe battery charging.
- Consumer Electronics: Used in a variety of consumer electronics that require efficient battery management.
Q & A
- What is the operating input supply range of the LTC4121?
The operating input supply range is from 4.4V to 40V. - What are the battery voltage ranges for the LTC4121 and LTC4121-4.2?
The LTC4121 supports a battery voltage range of 0V to 18V, while the LTC4121-4.2 supports a range of 0V to 4.2V. - What is the typical DC supply current in switching mode?
The typical DC supply current in switching mode is 3.5mA. - What is the minimum controllable on-time for the LTC4121?
The minimum controllable on-time is 120ns. - What is the duty cycle maximum for the LTC4121?
The duty cycle maximum is 94%. - What are the RDSON values for the top and bottom switches?
The top switch RDSON is 0.8Ω, and the bottom switch RDSON is 0.5Ω. - What is the peak inductor current limit for the LTC4121?
The peak inductor current limit is between 585mA and 1250mA, measured across RSNS with a 15µH inductor. - Does the LTC4121 support NTC temperature qualified charging?
Yes, the LTC4121 supports NTC temperature qualified charging. - What is the operating temperature range for the LTC4121IUD#TRPBF?
The operating temperature range is from –40°C to 125°C. - What are some common applications for the LTC4121?
The LTC4121 is commonly used in portable electronics, industrial battery systems, automotive systems, medical devices, and consumer electronics.
