ACS761
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ACS761ELF-20B 12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC Features and Benefits ▪ Hall-effect current monitor—no external sense resistor required ¯¯¯ ¯ ¯ PG ¯¯¯¯ ▪ PGOOD and ¯¯¯ OOD indication ▪ Analog output voltage (factory trimmed for gain and offset) proportional to applied current ▪ External high-side FET gate drive ▪ 240V*A power fault protection with user-selectable delay ▪ Overcurrent fault protection with user-selectable delay ▪ Fault protection isolates failed supply from output in < 2 μs ▪ 1.5 mΩ internal conductor resistance ▪ Active low latched Fault indicator output signal ▪ User controlled soft start / hot-swap function ▪ Logic enable input pin ▪ 10.8 to 13.2 V, single-supply operation ▪ 2 kV ESD protection for all pins The ACS761 combines Allegro™ Hall-effect current sense technology with a hot-swap controller resulting in a more efficient integrated controller for 12 V applications. By eliminating the need for a shunt resistor, the I2R losses in the power path are reduced. When the ACS761 is externally enabled, and the voltage rail is above the internal UVLO threshold, the internal charge pump drives the gate of the external FET. When the load voltage reaches its target value PGOOD is asserted high. When a fault is detected, the gate is disabled while simultaneously alerting the application that a fault has occurred. The integrated protection in the ACS761 incorporates three levels of fault protection, which includes a Power Fault with user-selectable delay, an Overcurrent Fault threshold with userselectable delay, and Short Circuit protection, which disables the gate in less than 2 μs. These faults are indicated to the host system via the Fault pin and are cleared upon reasserting enable high. Package: 24 pin QSOP (suffix LF) Approximate Scale

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC Selection Guide Part Number ACS761ELFTR-20B-T QSOP24 surface mount *Contact Allegro for additional packing options Absolute Maximum Ratings Characteristic GATE Drive Output Voltage* All Other Pins Forward Voltage Reverse DC Voltage, All Pins* Forward Voltage, IPx pins* Reverse Transient DC Voltage, All Pins* Current Sense Output Current Source Current Sense Output Current Sink Maximum Junction Temperature Operating Ambient Temperature Storage Temperature Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts...

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC Terminal List Table Number 1-6 7 8 9 Function Primary sampled current conduction path input; power input pins: connected to VCC. Enable pin. The falling edge on the EN pin clears an overpower, overcurrent, or short circuit fault. Analog output. Output voltage on this pin is proportional to the current flowing from the IP+ pins to the IP– pins. No connect. Connection to ground is recommended. Terminal for CG capacitor. May be used to adjust the turn-on time and soft start control of an external MOSFET, S1. Voltage on this pin...

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC Functional Block Diagram Hall Current Drive PGOOD OPDLY Short Circuit Detection Dynamic Offset Cancellation Charge Pump OCDLY VIOUT Zero Current Output Voltage Adjustment OPDLY OCDLY PGOOD / Fault Logic FAULT Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC OPERATING CHARACTERISTICS valid at VCC = 12 V, TA = 0°C to 85°C, unless otherwise noted Characteristic General Electrical Characteristics Source Current Linear Sensing Range Primary Conductor Resistance Supply Voltage Supply Current Undervoltage Lockout (UVLO) Symbol ISOURCE IP RPRIMARY VCC ICC VUVLOH VUVLOL tUVLOE UVLO Delay to Chip Enable/ Disable tUVLOD FB+ Input Resistance RFB Current Sense Performance Characteristics VIOUT Analog Output Propagation tPROP Time VIOUT Analog Output 10-90% Rise tr Time VIOUT Load Capacitance...

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC OPERATING CHARACTERISTICS (continued) valid at VCC = 12 V, TA = 0°C to 85°C, unless otherwise noted Characteristic Symbol Operational Supply Indicator Performance Characteristics Test Conditions PGOOD Output Voltage IPGOOD = 3 mA sink current PGOOD Output Leakage Current PGOOD Activation Threshold PGOOD Deactivation Threshold ¯ ¯ ¯ ¯ ¯ Output Voltage ¯ ¯ ¯ ¯¯ PGOOD I¯ ¯¯¯¯¯¯¯ = 3 mA sink current ¯ ¯ PGOOD ¯ ¯ ¯ ¯ ¯ Output Leakage Current ¯ ¯ ¯ ¯¯ PGOOD V¯ ¯¯¯¯¯¯¯ HIGH TA = 25°C; FB+ = 0 V → 12 V ¯ ¯ PGOOD ¯ ¯ ¯ ¯ ¯ Deactivation...

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC OPERATING CHARACTERISTICS (continued) valid at VCC = 12 V, TA = 0°C to 85°C, unless otherwise noted Characteristic Symbol Gate Drive Performance Characteristics Nominal Gate Voltage VGATE Gate Voltage Tolerance ΔVGATE Average GATE Drive Current IGD Charge Pump Switching Frequency fCP GATE Rise Time GATE Sink Resistance7 GATE Sink Steady State Resistance7 GATE Shutdown Delay Test Conditions TA = 25°C TA = 25°C VCC = 12 V, TA = 25°C TA = 25°C TA = 25°C, external MOSFET S1 gate capacitance = 5.8 nF, measured from VGATE = 0 to 15 V,...

12 V High-Side Hot-Swap Hall Effect Based Current Monitor IC Functional Description Soft Start and Fault Characteristics Gate turn on rise time, tGR. Set by external capacitance, CG, on the CG pin, such that CG = 7.5 × tGR , where CG is in F and tGR is rise time in seconds. For example, a 3.9 F capacitor connected from the CG pin to GND (without an output load) will yield a rise time of approximately 500 ms: CG 7.5 × 0.5 s = 3.75 F, 3.9 F (a common capacitor value). When the CG pin is kept open, the ACS761 has a minimum tGR of 1 ms typical. It is important to select values for CG and the...