LTC4252B/LTC4252C - Negative Voltage Hot Swap Controllers
Features
- Allows Safe Board Insertion and Removal from a Live –48V Backplane
- Floating Topology Permits Very High Voltage Operation
- Current Limit With Circuit Breaker Timer
- Fast Response Time Limits Peak Fault Current
- Programmable Soft-Start Current Limit
- Programmable Timer with Drain Voltage Accelerated Response
- ±1% Undervoltage/Overvoltage Threshold (LTC4252C)
- Improved Ruggedness Shunt Regulator
- Adjustable Undervoltage/Overvoltage Protection
- LTC4252B-1/LTC4252C-1: Latch Off After Fault
- LTC4252B-2/LTC4252C-2: Automatic Retry After Fault
- Available in 8-Pin and 10-Pin MSOP Packages
Typical Application
Description
The LTC®4252 negative voltage Hot SwapTM controller allows a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions.
Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4252’s supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial startup and controls the circuit breaker’s response time. The circuit breaker’s response time is accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up.
The LTC4252-2 provides automatic retry after a fault. The LTC4252C-1/LTC4252C-2 feature tight ±1% undervoltage/ overvoltage threshold accuracy. The LTC4252 is available in either an 8-pin or 10-pin MSOP.
The LTC4252B and LTC4252C improve the ruggedness of the shunt regulator in the LTC4252 and LTC4252A.
| UV/OV % |
Latch Off/Retry | Package | |
| LTC4252-1 | 4.6% | Latch off | MS-8, MS-10 |
| LTC4252-2 | 4.8% | Retry | MS-8, MS-10 |
| LTC4252A-1 | 1% | Latch off | MS-10 |
| LTC4252A-2 | 1% | Retry | MS-10 |
| LTC4252B-1 | 4.6% | Latch off | MS-8, MS-10 |
| LTC4252B-2 | 4.6% | Retry | MS-8, MS-10 |
| LTC4252C-1 | 1% | Latch off | MS-10 |
| LTC4252C-2 | 1% | Retry | MS-10 |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC4252BCMS-1#PBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252BCMS-1#TRPBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252BCMS-2#PBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252BCMS-2#TRPBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252BCMS8-1#PBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4252BCMS8-1#TRPBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4252BCMS8-2#PBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4252BCMS8-2#TRPBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4252BIMS-1#PBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252BIMS-1#TRPBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252BIMS-2#PBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252BIMS-2#TRPBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252BIMS8-1#PBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC4252BIMS8-1#TRPBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC4252BIMS8-2#PBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC4252BIMS8-2#TRPBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC4252CCMS-1#PBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252CCMS-1#TRPBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252CCMS-2#PBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252CCMS-2#TRPBF | MS-10 | MS | C | 05-08-1661 | Yes |
| LTC4252CIMS-1#PBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252CIMS-1#TRPBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252CIMS-2#PBF | MS-10 | MS | I | 05-08-1661 | Yes |
| LTC4252CIMS-2#TRPBF | MS-10 | MS | I | 05-08-1661 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
sales office or authorized distributor.Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC787A-A | LTC4252CCMS-1 Demoboard | Negative Voltage Hot Swap Controller in an AdvancedTCA Application, Latch Off After Fault | $75.00 | |
| DC787A-B | LTC4252CCMS-2 Demoboard | Negative Voltage Hot Swap Controller in an AdvancedTCA Application, Auto Retry After Fault | $75.00 | |
| Buy Now | |||
Applications
- Hot Board Insertion
- Electronic Circuit Breaker
- –48V Distributed Power Systems
- Negative Power Supply Control
- Central Office Switching
- High Availability Servers
- ATCA
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Design Tools
LTspice
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Models for the following parts are available in LTspice:
LTC4252A-1
LTC4252A-2
LTC4252C-1
LTC4252C-2
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
