DocumentationDatasheet
Design Note
Reliability Data
Product Selector Card
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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 |
MS-10,MS-8
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC4252-1CMS#PBF | MSOP | 10 | C | $3.00 | $2.35 |
| LTC4252-1CMS#TRPBF | MSOP | 10 | C | $2.41 | |
| LTC4252-1CMS8#PBF | MSOP | 8 | C | $2.55 | $2.00 |
| LTC4252-1CMS8#TRPBF | MSOP | 8 | C | $2.06 | |
| LTC4252-1IMS#PBF | MSOP | 10 | I | $3.40 | $2.65 |
| LTC4252-1IMS#TRPBF | MSOP | 10 | I | $2.71 | |
| LTC4252-1IMS8#PBF | MSOP | 8 | I | $2.90 | $2.30 |
| LTC4252-1IMS8#TRPBF | MSOP | 8 | I | $2.36 | |
| LTC4252-2CMS#PBF | MSOP | 10 | C | $3.00 | $2.35 |
| LTC4252-2CMS#TRPBF | MSOP | 10 | C | $2.41 | |
| LTC4252-2CMS8#PBF | MSOP | 8 | C | $2.55 | $2.00 |
| LTC4252-2CMS8#TRPBF | MSOP | 8 | C | $2.06 | |
| LTC4252-2IMS#PBF | MSOP | 10 | I | $3.40 | $2.65 |
| LTC4252-2IMS#TRPBF | MSOP | 10 | I | $2.71 | |
| LTC4252-2IMS8#PBF | MSOP | 8 | I | $2.90 | $2.30 |
| LTC4252-2IMS8#TRPBF | MSOP | 8 | I | $2.36 | |
| LTC4252A-1CMS#PBF | MSOP | 10 | C | $3.45 | $2.50 |
| LTC4252A-1CMS#TRPBF | MSOP | 10 | C | $2.56 | |
| LTC4252A-1IMS#PBF | MSOP | 10 | I | $3.90 | $2.90 |
| LTC4252A-1IMS#TRPBF | MSOP | 10 | I | $2.96 | |
| LTC4252A-2CMS#PBF | MSOP | 10 | C | $3.45 | $2.50 |
| LTC4252A-2CMS#TRPBF | MSOP | 10 | C | $2.56 | |
| LTC4252A-2IMS#PBF | MSOP | 10 | I | $3.90 | $2.90 |
| LTC4252A-2IMS#TRPBF | MSOP | 10 | I | $2.96 | |
| LTC4252BCMS-1#PBF | MSOP | 10 | C | $3.00 | $2.35 |
| LTC4252BCMS-1#TRPBF | MSOP | 10 | C | $2.41 | |
| LTC4252BCMS-2#PBF | MSOP | 10 | C | $3.00 | $2.35 |
| LTC4252BCMS-2#TRPBF | MSOP | 10 | C | $2.41 | |
| LTC4252BCMS8-1#PBF | MSOP | 8 | C | $2.55 | $2.00 |
| LTC4252BCMS8-1#TRPBF | MSOP | 8 | C | $2.06 | |
| LTC4252BCMS8-2#PBF | MSOP | 8 | C | $2.55 | $2.00 |
| LTC4252BCMS8-2#TRPBF | MSOP | 8 | C | $2.06 | |
| LTC4252BIMS-1#PBF | MSOP | 10 | I | $3.40 | $2.65 |
| LTC4252BIMS-1#TRPBF | MSOP | 10 | I | $2.71 | |
| LTC4252BIMS-2#PBF | MSOP | 10 | I | $3.40 | $2.65 |
| LTC4252BIMS-2#TRPBF | MSOP | 10 | I | $2.71 | |
| LTC4252BIMS8-1#PBF | MSOP | 8 | I | $2.90 | $2.30 |
| LTC4252BIMS8-1#TRPBF | MSOP | 8 | I | $2.36 | |
| LTC4252BIMS8-2#PBF | MSOP | 8 | I | $2.90 | $2.30 |
| LTC4252BIMS8-2#TRPBF | MSOP | 8 | I | $2.36 | |
| LTC4252CCMS-1#PBF | MSOP | 10 | C | $3.45 | $2.50 |
| LTC4252CCMS-1#TRPBF | MSOP | 10 | C | $2.56 | |
| LTC4252CCMS-2#PBF | MSOP | 10 | C | $3.45 | $2.50 |
| LTC4252CCMS-2#TRPBF | MSOP | 10 | C | $2.56 | |
| LTC4252CIMS-1#PBF | MSOP | 10 | I | $3.90 | $2.90 |
| LTC4252CIMS-1#TRPBF | MSOP | 10 | I | $2.96 | |
| LTC4252CIMS-2#PBF | MSOP | 10 | I | $3.90 | $2.90 |
| LTC4252CIMS-2#TRPBF | MSOP | 10 | I | $2.96 | |
| LTC4252-1CMS | MSOP | 10 | C | $6.00 | $4.70 |
| LTC4252-1CMS8 | MSOP | 8 | C | $5.10 | $4.00 |
| LTC4252-1IMS | MSOP | 10 | I | $6.80 | $5.30 |
| LTC4252-1IMS8 | MSOP | 8 | I | $5.80 | $4.60 |
| LTC4252-1CMS#TR | MSOP | 10 | C | $4.82 | |
| LTC4252-1CMS8#TR | MSOP | 8 | C | $4.12 | |
| LTC4252-1IMS#TR | MSOP | 10 | I | $5.42 | |
| LTC4252-1IMS8#TR | MSOP | 8 | I | $4.72 | |
| LTC4252-2CMS8 | MSOP | 8 | C | $5.10 | $4.00 |
| LTC4252-2IMS | MSOP | 10 | I | $6.80 | $5.30 |
| LTC4252-2IMS8 | MSOP | 8 | I | $5.80 | $4.60 |
| LTC4252-2CMS#TR | MSOP | 10 | C | $4.82 | |
| LTC4252-2CMS8#TR | MSOP | 8 | C | $4.12 | |
| LTC4252-2IMS#TR | MSOP | 10 | I | $5.42 | |
| LTC4252-2IMS8#TR | MSOP | 8 | I | $4.72 | |
| LTC4252-2CMS | MSOP | 10 | C | $6.00 | $4.70 |
| LTC4252A-1CMS | MSOP | 10 | C | $6.90 | $5.00 |
| LTC4252A-1CMS#TR | MSOP | 10 | C | $5.12 | |
| LTC4252A-1IMS | MSOP | 10 | I | $7.80 | $5.80 |
| LTC4252A-1IMS#TR | MSOP | 10 | I | $5.92 | |
| LTC4252A-2CMS | MSOP | 10 | C | $6.90 | $5.00 |
| LTC4252A-2CMS#TR | MSOP | 10 | C | $5.12 | |
| LTC4252A-2IMS | MSOP | 10 | I | $7.80 | $5.80 |
| LTC4252A-2IMS#TR | MSOP | 10 | I | $5.92 |
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 |