UCC3918DPTRG4

           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 D Integrated 0.075-Ω Power MOSFET D 3 V to 6 V Operation D External Analog Control of Fault Current D D D D D D D D DP PACKAGE (TOP VIEW) VIN VIN VIN GND* GND* FAULT SHTDWN IFAULT from 0 A to 4 A Independent Analog Control of Current Limit Up to 5 A Fast Overload Protection Unidirectional Switch Minimal External Components 1-µA ICC When Disabled Programmable On Time Programmable Start Delay Fixed 3% Duty Cycle 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VOUT VOUT VOUT GND* GND* NC CT IMAX Pin 5 serves as the lowest impedance to the electrical ground. Pins 4, 12, and 13, serve as heat sink/ground. These pins should be connected to large etch PCB areas to help dissipate heat. description The UCC3918 low on-resistance hot swap power manager provides complete power management, hot swap capability, and circuit breaker functions. The only components needed to operate the device, other than supply bypassing, are a timing capacitor, and two programming resistors. All control and housekeeping functions are integrated, and externally programmable. These include the fault current level, maximum output sourcing current, maximum fault time, and startup delay. In the event of a constant fault, the internal fixed 3% duty cycle ratio limits the average output power. The IFAULT pin allows linear programming of the fault level current from 0 A to 4 A. Fast overload protection is accomplished by an additional overload comparator. Its threshold is internally set above the maximum sourcing current limit setting. In the event of a short circuit or extreme current condition, this comparator is tripped, shutting down the output. This function is needed since the maximum sourcing current limit loop has a finite bandwidth. When the output current is below the fault level, the output MOSFET is switched on with a nominal resistance of 0.075 Ω. When the output current exceeds the fault level or the maximum sourcing level, the output remains on, but the fault timer starts charging a capacitor connected to the CT pin (CT). Once CT charges to a preset threshold, the switch is turned off, and remains off for 30 times the programmed fault time. When the output current reaches the maximum sourcing level, the MOSFET transitions from a switch to a constant current source. The UCC3918 is designed for unidirectional current flow, emulating an ideal diode in series with the power switch. This feature is particularly attractive in applications where many devices are powering a common bus, such as with SCSI termintation power (Termpwr). The UCC3918 can also be put into the sleep mode, drawing only 1 µA of supply current. Other features include an open-drain fault output indicator, thermal shutdown, undervoltage lockout, 3 V to 6 V operation, and a low thermal resistance small-outline power package. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright  2000, Texas Instruments Incorporated  
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           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 functional block diagram CHARGE PUMP OVERLOAD COMPARATOR 1 VIN REVERSE COMPARATOR + 2 VIN 20mV + 3 VIN + VOUT + CURRENT SENSE H = OPEN + IMAX 9 MAXIMUM CURRENT LEVEL CURRENT FAULT LEVEL OVERCURRENT COMPARATOR + IFAULT 8 14 VOUT ON TIME CONTROL 15 VOUT 3% DUTY CYCLE 16 VOUT THERMAL SHUTDOWN 1.5V INTERNAL BIAS 5 GND 4 13 12 HEAT SINK GND PINS 10 6 CT FAULT + 7 SHTDWN UDG–99153 absolute maximum ratings over operating free-air temperature (unless otherwise noted)†} Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 V SOIC Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 W Fault output sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 mA Fault output voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VIN Output Current (dc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited Input Voltage SHTDWN, IFAULT, IMAX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VIN Storage temperature range Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65_C to 150_C Operating virtual junction temperature TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55_C to 150_C Lead temperature (soldering, 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300_C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. ‡ Unless otherwise indicated, voltages are reference to ground and currents are positive into, negative out of the specified terminal. Pulsed is defined as a less than 10% duty cycle with a maximum duration of 500 µs. Consult Packaging Section of Databook for thermal limitations and considerations of package. 2 www.ti.com 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 electrical characteristics at TA = 0°C to 70°C, VIN = 5 V, RIMAX = 42.2 kΩ, RIFAULT = 52.3 kΩ, SHTDWN = 2.4 V, TA = TJ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 3 5 6 V 1 2 mA 0.5 5 µA 0.075 0.095 Ω Supply Section Voltage input range, VIN VDD supply current No load Sleep mode current SHTDWN = 0.2 V Output Section IOUT = 1 A to 4 A, IOUT = 1 A to 4 A, VIN = 5 V, 0.09 0.116 Ω IOUT = 1 A to 4 A, IOUT = 1A to 4A, VIN = 5 V 0.075 0.125 Ω VIN = 3 V 0.09 0.154 Ω Reverse leakage current SHTDWN = 0 V, VIN = 0 V 20 µA Initial startup time See Note 1 Thermal shutdown VIN = 5 V, Thermal hysteresis See Note 1 Output leakage SHTDWN = 0.2 V, RDS(on) Trip current VIN = 3 V, TA = 25°C TA = 25°C VOUT = 5 V See Note 1 100 µs 170 _C _C 10 VOUT = 0 V 20 µA RIFAULT = 105 kΩ 0.75 1 1.25 A RIFAULT = 52.3 kΩ 1.7 2 2.3 A RIFAULT = 34.8 kΩ 2.5 3 3.5 A RIFAULT = 25.5 kΩ 3.3 4 4.7 A RIMAX = 118 kΩ 0.3 1 1.7 A 1 2 3 A RIMAX = 60.4 kΩ RIMAX = 42.2 kΩ 2 3 4 A RIMAX = 33.2 kΩ 2.5 3.8 5.1 A RIMAX = 27.4 kΩ 3.0 4.6 6.2 A –50 –36 –22 µA CT discharge current VCT = 1 V VCT = 1 V 0.5 1.2 2.0 µA Output duty cycle VOUT = 0 V 1.5 3 6 % CT fault threshold 0.8 1.3 1.8 V CT reset threshold 0.25 0.5 0.75 V 1.5 2.0 output Maximum out ut current Fault Section CT charge current Shutdown Section Shutdown threshold 1.1 Shutdown hysteresis 100 V mV Input low current SHTDWN = 0V –500 0 500 nA Input high current SHTDWN = 2V –2 –1 –0.5 µA 1 µA 0.4 0.9 V Open Drain Fault Output Section High level output current Low level output voltage IOUT = 1mA NOTE 1: Ensured by design. Not production tested. www.ti.com 3 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 pin descriptions CT: A capacitor connected to this pin sets the maximum fault time. The maximum time must be greater than the time to charge external load capacitance. The nominal fault time is defined as: T FAULT 10 3 + 22.2 C T (1) Once the fault time is reached the output shuts down for a time given by: T SD + 0.667 10 6 C T (2) This equates to a 3% duty cycle. The recommended minimum value for the CT capacitor is 0.1 µF. FAULT: Open-drain output, which pulls low on any condition that causes the output to open; Fault, Thermal Shutdown, Shutdown, and maximum sourcing current greater than the fault time. GND: This is the most negative voltage in the circuit. All 4 ground pins should be used, and properly heat sunk on the PCB. IFAULT: A resistor connected from this pin to ground sets the fault threshold. The resistor versus fault current is set by the formula R FAULT + 105 kW I TRIP (3) IMAX: A resistor connected from this pin to ground sets the maximum sourcing current. The resistor vs the output sourcing current is set by the formula: R IMAX + 126 kW Maximum Sourcing Current (4) SHTDWN: When this pin is brought low, the IC is put into sleep mode. The input threshold is hysteretic, allowing the user to program a startup delay with an external RC circuit. VIN: This is the input voltage to the UCC3918. The recommended operating voltage range is 3V to 6V. All VIN pins should be connected together and to the power source. VOUT: Output voltage for the circuit breaker. When switched the output voltage will be approximately: V OUT +V IN * 0.075W I OUT . (5) All VOUT pins should be connected together and to the load. 4 www.ti.com 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 APPLICATION INFORMATION HEAT SINK GND PINS 4 VIN D1 R1 CIN 1 VIN 2 VIN 3 VIN 6 FAULT 10 CT 12 GND 13 5 VOUT 14 VOUT 15 VOUT RL COUT VOUT 16 RSD CT SHTDWN IFAULT IMAX 8 9 RIFAULT 7 S6 VIN CSD RIMAX UDG–99152 Figure 1. Typical Application protecting the UCC3918 from voltage transients The parasitic inductance associated with the power distribution can cause a voltage spike at VIN if the load current is suddenly interrupted by the UCC3918. It is important to limit the peak of this spike to less than 6 V to prevent damage to the UCC3918. This voltage spike can be minimized by: • • • Reducing the power distribution inductance (e.g., twist the positive “+” and negative “–” leads of the power supply feeding VIN, locate the power supply close to the UCC3918 or use a PCB ground plane). Decoupling VIN with a capacitor, CIN (refer to Figure 1), located close to the VIN pin. This capacitor is typically less than 1 µF to limit the inrush current. Clamping the voltage at VIN below 6 V with a Zener diode, D1 (refer to Figure 1), located close to the VIN pin. estimating maximum load capacitance For circuit breaker applications, the rate at which the total output capacitance can be charged depends on the maximum output current available and the nature of the load. For a constant-current current-limited circuit breaker, the output comes up if the load requires less than the maximum available short-circuit current. To ensure recovery of a duty-cycle of the current-limited circuit breaker from a short-circuited load condition, there is a maximum total output capacitance that can be charged for a given unit ON time (fault time). The design value of ON or fault time can be adjusted by changing the timing capacitor CT. www.ti.com 5 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 APPLICATION INFORMATION estimating maximum load capacitance For worst-case constant-current load of value just less than the trip limit; COUT(max) can be estimated from: ǒ Ǔ C + ǒI *I MAX OUT(max) LOAD 22 10 3 V OUT C T Ǔ (6) Where VOUT is the output voltage and IMAX is the maximum sourcing current. For a resistive load of value RLOAD, the value of COUT(max) can be estimated from: ȡ ȧ ȧ ȧ C +ȧ OUT(max) ȧ ȧ ȧR ȧ LOAD Ȣ ȣ ȧ ȧ ȧ 22 10 3 C T ȧ ȧ ȡ ȣȧ ȧ 1 ȏnȧ ȧ ȧ VOUT 1* Ȣ IMAX RLOADȤȤ (7) UDG–97071 Figure 2. Load Curent, Timing Capacitor Voltage and Output Voltage of the UCC3918 Under Fault 6 www.ti.com 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 TYPICAL CHARACTERISTICS REVERSE VOLTAGE COMPARATOR RESPONSE TIME FAULT TIMING WAVEFORMS VIN COUT = 22 F CT (0.1 F) RLOAD = 5 CIN = 5 F 4A RIFAULT = 52.3 k RIMAX = 42.0 k 3A FAULT OUT VOUT = 0 V 2A RLOAD = SHORT CIN = 5 F 1A RIFAULT = 52.3 k IIN RIMAX = 42.2 k 0A OUTPUT CURRENT Figure 3 Figure 4 INRUSH CURRENT LIMITING FAULT AND OUTPUT TURN-OFF DELAY FROM CT FAULT THRESHOLD CT COUT = 22 F VOUT RLOAD = 5 COUT = 0 F CIN = 5 F RLOAD = 5 RIFAULT = 52.3 k FAULT OUT RIMAX = 60.4 k CIN = 5 F VOUT 0V IOUT (RLOAD = 5 0A IINPUT @ 0.5 A/DIV ) CT = OPEN RIFAULT = 52.3 k RIMAX = 42.4 k Figure 5 Figure 6 www.ti.com 7 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 TYPICAL CHARACTERISTICS PROPAGATION DELAY SHUTDOWN TO FAULT AND OUTPUT RAMP-DOWN PROPAGATION DELAY ENABLE TO FAULT AND OUTPUT RAMP-UP SHUTDOWN SHUTDOWN COUT = 0 F FAULT OUT FAULT OUT RLOAD = 5 CIN = 5 F COUT = 0 F VOUT RLOAD = 5 VOUT RIFAULT = 52.3 k CIN = 5 F RIMAX = 42.4 k 1A IOUT RIFAULT = 52.3 k IOUT (RLOAD = 5 RIMAX = 42.4 k ) 0A Figure 7 Figure 8 ON-STATE RESISTANCE vs TEMPERATURE ON-STATE RESISTANCE vs OUTPUT CURRENT 125 VIN = 3 V, I = 1 A 115 RDS(on) On–State Resistance – m RDS(on) On–State Resistance – m 110 105 95 85 75 65 55 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 VIN = 5 V, I = 1 A 90 Average 80 70 VIN = 5 V, I = 4 A 60 50 VIN = 3 V, I = 4 A 40 – 40 0 40 80 TA – Free-Air Temperature – _C IOUT – Output Current – A Figure 10 Figure 9 8 100 www.ti.com 120 
           SLUS384B – NOVEMBER 1999 – REVISED JUNE 2000 APPLICATION INFORMATION safety considerations Although the UCC3918 is designed to provide system protection for all fault conditions, all integrated circuits can ultimately fail short. For this reason, if the UCC3918 is intended for use in safety critical applications where UL or some other safety rating is required, a redundant safety device such as a fuse should be placed in series with the power device. The UCC3918 prevents the fuse from blowing for virtually all fault conditions, increasing system reliability and reducing maintenance cost, in addition to providing the hot swap benefits of the device. www.ti.com 9 PACKAGE OPTION ADDENDUM www.ti.com 13-Aug-2021 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) (3) Device Marking (4/5) (6) UCC3918DP ACTIVE SOIC D 16 40 RoHS & Green NIPDAU Level-2-260C-1 YEAR 0 to 70 UCC3918DP UCC3918DPG4 ACTIVE SOIC D 16 40 RoHS & Green NIPDAU Level-2-260C-1 YEAR 0 to 70 UCC3918DP UCC3918DPTR ACTIVE SOIC D 16 2500 RoHS & Green NIPDAU Level-2-260C-1 YEAR 0 to 70 UCC3918DP (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of