Overview
The ADM1278-1AACPZ, produced by Analog Devices Inc., is a hot swap controller designed to enable the safe insertion or removal of a circuit board from a live backplane. This component integrates a range of features including current, voltage, power, and temperature monitoring through a 12-bit analog-to-digital converter (ADC) accessible via a PMBus interface. It ensures safe and controlled power management by limiting current, detecting overcurrent and short-circuit conditions, and providing overvoltage and undervoltage protection.
Key Specifications
| Parameter | Symbol | Min | Typ | Max | Unit | Test Conditions/Comments |
|---|---|---|---|---|---|---|
| Operating Voltage Range | VCC | 4.5 | 20 | V | VCC ≥ VHS+, VHS+ = 2 V to 20 V, TA = −40°C to +85°C | |
| Undervoltage Lockout | UVLO | 2.4 | 2.7 | V | VCC rising | |
| Undervoltage Hysteresis | 90 | 120 | mV | |||
| Quiescent Current | ICC | 5.5 | mA | GATE on and power monitor running | ||
| UV PIN Input Current | IUV | 50 | nA | UV ≤ 3.6 V | ||
| Input High Voltage | VIH | 2.0 | V | |||
| Input Low Voltage | VIL | 0.8 | V | |||
| Output Low Voltage | VOL | 0.4 | V | IOL = 4 mA | ||
| Leakage Current | 1 | μA | ||||
| Data Rate | 1 | MHz |
Key Features
- Hot swap capability allowing safe insertion or removal of circuit boards from a live backplane.
- Integrated 12-bit ADC for current, voltage, power, and temperature monitoring via PMBus interface.
- Current limiting and overcurrent protection with fast internal overcurrent detector responding within 320 ns.
- Overvoltage (OV) and undervoltage (UV) protection using external resistor dividers.
- Constant power foldback scheme to control power dissipation in the MOSFET during power-up and fault conditions.
- PWRGD signal for detecting valid output supply.
- Available in a 32-lead LFCSP package with RETRY pin for automatic retry or latch-off configuration.
Applications
- Storage networks
- Hard drives
- Datacom systems
- Distributed power systems.
Q & A
- What is the primary function of the ADM1278-1AACPZ? The primary function is to act as a hot swap controller, allowing safe insertion or removal of circuit boards from a live backplane while monitoring and controlling power parameters.
- How does the ADM1278-1AACPZ monitor power parameters? It uses an integrated 12-bit ADC accessible via a PMBus interface to monitor current, voltage, power, and temperature.
- What kind of protection does the ADM1278-1AACPZ offer? It offers overcurrent, overvoltage, and undervoltage protection, as well as a fast internal overcurrent detector.
- How is the current limit set in the ADM1278-1AACPZ? The current limit is set by measuring the voltage across a sense resistor in the power path and can be adjusted using external components.
- What is the purpose of the RETRY pin in the ADM1278-1AACPZ? The RETRY pin can be configured for automatic retry or latch-off when an overcurrent fault occurs.
- What is the operating voltage range of the ADM1278-1AACPZ? The operating voltage range is from 4.5 V to 20 V.
- How does the ADM1278-1AACPZ protect the external MOSFET? It protects the MOSFET by limiting the time it remains on while the current is at its maximum value and using a constant power foldback scheme during power-up and fault conditions.
- What is the typical quiescent current of the ADM1278-1AACPZ? The typical quiescent current is 5.5 mA.
- In what package is the ADM1278-1AACPZ available? It is available in a 32-lead LFCSP package.
- What are some common applications of the ADM1278-1AACPZ? Common applications include storage networks, hard drives, datacom systems, and distributed power systems.
