LTC1154 High-Side Micropower MOSFET Driver U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ Fully Enhances N-Channel Power MOSFETs 8µA IQ Standby Current 85µA IQ ON Current No External Charge Pump Capacitors 4.5V to 18V Supply Range Short-Circuit Protection Thermal Shutdown via PTC Thermistor Status Output Indicates Shutdown Available in 8-Pin SOIC The LTC1154 single high-side gate driver allows using low cost N-channel FETs for high-side switching applications. An internal charge pump boosts the gate drive voltage above the positive rail, fully enhancing an N-channel MOS switch with no external components. Micropower operation, with 8µA standby current and 85µA operating current, allows use in virtually all systems with maximum efficiency. Included on chip is programmable over-current sensing. A time delay can be added to prevent false triggering on high in-rush current loads. An active high shutdown input is also provided and interfaces directly to a standard PTC thermistor for thermal shutdown. An open-drain output is provided to report switch status to the µP. An active low enable input is provided to control multiple switches in banks. UO APPLICATI ■ ■ ■ ■ ■ Laptop Computer Power Switching SCSI Termination Power Switching Cellular Telephone Power Management Battery Charging and Management High-Side Industrial and Automotive Switching Stepper Motor and DC Motor Control The LTC1154 is available in both 8-pin DIP and 8-pin SOIC packages. UO ■ S TYPICAL APPLICATI Ultra-Low Voltage Drop High-Side Switch with Short-Circuit Protection Standby Supply Current 50 5V 51k 0.036Ω* IN VS 200k** EN DS LTC1154 STATUS GND IRLR024 G SD 5V LOAD SUPPLY CURRENT (µA) 40 0.1µF** µP VIN = 0V TJ = 25°C 45 2.7A MAX 35 30 25 20 15 10 5 ALL COMPONENTS SHOWN ARE SURFACE MOUNT. * IMS026 INTERNATIONAL MANUFACTURING SERVICE, INC. (401) 683-9700 ** NOT REQUIRED IF LOAD IS RESISTIVE OR INDUCTIVE. LTC1154 • TA01 0 0 5 10 15 SUPPLY VOLTAGE (V) 20 LTC1153 • TA02 1 LTC1154 W W W AXI U U ABSOLUTE RATI GS Supply Voltage ........................................................ 22V Input Voltage ..................... (VS + 0.3V) to (GND – 0.3V) Enable Input Voltage .......... (VS + 0.3V) to (GND – 0.3V) Gate Voltage ....................... (VS + 24V) to (GND – 0.3V) Status Output Voltage .............................................. 15V Current (Any Pin).................................................. 50mA Operating Temperature LTC1154C .............................................. 0°C to 70°C Storage Temperature Range ................. – 65°c to 150°C Lead Temperature (Soldering, 10 sec.)................ 300°C U W U PACKAGE/ORDER I FOR ATIO TOP VIEW IN 1 8 VS ENABLE 2 7 DRAIN SENSE STATUS 3 6 GATE GND 4 5 SHUTDOWN ORDER PART NUMBER LTC1154CN8 ORDER PART NUMBER TOP VIEW IN 1 8 VS ENABLE 2 7 DRAIN SENSE STATUS 3 6 GATE GND 4 5 SHUTDOWN S8 PACKAGE 8-LEAD PLASTIC SOIC N8 PACKAGE 8-LEAD PLASTIC DIP LTC1154 • PO01 LTC1154 • PO02 TJMAX = 100°C, θJA = 130°C/W (N8) LTC1154CS8 S8 PART MARKING 1154 TJMAX = 100°C, θJA = 150°C/W ELECTRICAL CHARACTERISTICS VS = 4.5V to 18V, TA = 25°C, VEN = 0V, VSD = 0V unless otherwise noted. CONDITIONS MIN LTC1154C TYP SYMBOL PARAMETER VS Supply Voltage IQ Quiescent Current OFF VS = 5V, VIN = 0V IQ Quiescent Current ON VS = 5V, VIN = 5V IQ Quiescent Current ON VS = 12V, VIN = 5V 180 VINH Input High Voltage ● VINL Input Low Voltage ● 0.8 V IIN Input Current ● ±1 µA CIN Input Capacitance VENH ENABLE Input High Voltage ● VENL ENABLE Input Low Voltage ● IEN ENABLE Input Current VSDH Shutdown Input High Voltage ● VSDL Shutdown Input Low Voltage ● ISD Shutdown Input Current VSEN Drain Sense Threshold Voltage ● 0V < VIN < VS 0V < VIN < VS 0V < VIN < VS 2 Drain Sense Input Current 0V < VSEN < VS UNITS 18.0 V 8 20 µA 85 120 µA 400 µA 4.5 2 3.5 V 5 pF 2.6 V 1.0 ● ● 0.6 V ±1 µA 2 V 0.8 ● ● ISEN MAX 80 75 100 100 V ±1 µA 120 125 mV mV ±0.1 µA LTC1154 ELECTRICAL CHARACTERISTICS VS = 4.5V to 18V, TA = 25°C, VEN = 0V, VSD = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VGATE – VS Gate Voltage Above Supply VS = 5V VS = 6V VS = 12V ● ● ● MIN LTC1154C TYP MAX UNITS 6.0 7.5 15.0 7.0 8.3 18.0 9.0 15.0 25.0 V V V 0.05 0.4 V 1 µA VSTAT Status Output Low Voltage ISTAT = 400µA ● ISTAT Status Output Leakage Current VSTAT = 12V ● tON Turn-ON Time VS = 5V, CGATE = 1000pF Time for VGATE > VS + 2V Time for VGATE > VS + 5V 30 100 110 450 300 1000 µs µs VS = 12V, CGATE = 1000pF Time for VGATE > VS + 5V Time for VGATE > VS + 10V 20 50 80 160 200 500 µs µs VS = 5V, CGATE = 1000pF Time for VGATE < 1V 10 36 60 µs VS = 12V, CGATE = 1000pF Time for VGATE < 1V 10 28 60 µs VS = 5V, CGATE = 1000pF Time for VGATE < 1V 5 25 40 µs VS = 12V, CGATE = 1000pF Time for VGATE < 1V 5 23 40 µs VS = 5V, CGATE = 1000pF Time for VGATE < 1V 17 40 µs VS = 12V, CGATE = 1000pF Time for VGATE < 1V 13 35 µs tOFF Turn-OFF Time tSC Short-Circuit Turn-OFF Time tSD Shutdown Turn-OFF Time The ● denotes specifications which apply over the operating temperature range. U W TYPICAL PERFOR A CE CHARACTERISTICS Standby Supply Current VIN = 0V TA = 25°C 24 TA = 25°C 900 SUPPLY CURRENT (µA) 40 35 30 25 20 15 22 800 20 700 18 VGATE – VS (V) 45 SUPPLY CURRENT (µA) High-Side Gate Voltage Supply Current ON 1000 50 600 500 400 16 14 12 300 10 10 200 8 5 100 6 0 0 0 0 5 10 15 SUPPLY VOLTAGE (V) 20 LTC1154 • TPC01 0 5 10 15 SUPPLY VOLTAGE (V) 20 LTC1154 • TPC02 0 5 10 15 SUPPLY VOLTAGE (V) 20 LTC1154 • TPC03 3 LTC1154 U W TYPICAL PERFOR A CE CHARACTERISTICS Input Threshold Voltage 2.0 VON 1.6 VOFF 1.4 1.2 1.0 0.8 0.6 0.4 5 0 30 140 27 130 24 120 21 110 18 100 90 9 6 60 3 5 0 Turn-ON Time Turn-OFF Time CGATE = 1000pF CGATE = 1000pF TIME FOR VGATE < 1V 400 VGS = 5V 200 VGS = 2V 100 40 35 30 25 20 15 5 0 0 5 0 900 Input ON Threshold Voltage 25 20 0 –50 –25 VIN = 5V VEN = 0V 2.2 800 30 VS = 18V 600 500 400 VS = 12V 200 100 VS = 5V 50 25 0 75 TEMPERATURE (°C) 700 300 100 125 LTC1154 • TPC10 20 10 15 SUPPLY VOLTAGE (V) 2.4 INPUT THRESHOLD VOLTAGE (V) VIN = 0V VEN = 0V 35 5 LTC1154 • TPC09 Supply Current ON SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 0 LTC1154 • TPC08 40 4 20 10 15 SUPPLY VOLTAGE (V) 1000 5 15 5 Standby Supply Current 50 10 20 10 LTC1153 • TPC07 15 25 5 20 10 15 SUPPLY VOLTAGE (V) 35 30 10 0 0 CGATE = 1000pF TIME FOR VGATE < 1V VSEN = VS – 1V NO EXTERNAL DELAY 45 TURN-OFF TIME (µs) TURN-OFF TIME (µs) TURN-ON TIME (µs) 500 10 Short-Circuit Turn-OFF Delay Time 40 700 6 8 4 SUPPLY VOLTAGE (V) 50 45 600 2 0 LTC1154 • TPC06 50 800 45 0 20 10 15 SUPPLY VOLTAGE (V) LTC1154 • TPC05 1000 300 12 70 LTC1154 • TPC04 900 15 80 50 20 10 15 SUPPLY VOLTAGE (V) 150 VGATE (V) DRAIN SENSE THRESHOLD VOLTAGE (V) INPUT THRESHOLD VOLTAGE (V) 2.2 1.8 Low-Side Gate Voltage Drain Sense Threshold Voltage 2.4 VS = 5V 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 2.0 1.8 1.6 1.4 1.2 1.O VS = 5V VS = 18V 0.8 0.6 100 125 LTC1154 • TPC11 0.4 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LTC1154 • TPC12 LTC1154 U W TYPICAL PERFOR A CE CHARACTERISTICS ENABLE Threshold Voltage 2.4 5.0 2.2 4.5 2.0 1.8 1.6 1.4 VS = 5V 1.2 VS = 18V 1.O 0.8 0.6 0.4 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 Gate Drive Current 1000 VS = 12V TA = 25°C 4.0 GATE DRIVE CURRENT (µA) ENABLE THRESHOLD VOLTAGE (V) SHUTDOWN THRESHOLD VOLTAGE (V) Shutdown Threshold Voltage 3.5 DISABLE 3.0 2.5 2.0 1.5 1.0 0.5 0 –50 –25 100 VS = 18V VS = 12V 10 VS = 5V 1 ENABLE 50 25 0 75 TEMPERATURE (°C) LTC1154 • TPC13 100 125 LTC1154 • TPC14 0.1 0 4 8 12 16 GATE VOLTAGE ABOVE SUPPLY (V) 20 LTC1154 • TPC15 U U U PI FU CTIO S Input and Shutdown Pins The LTC1154 input pin is active high and activates all of the protection and charge pump circuitry when switched ON. The shutdown pin is designed to immediately disable the switch if a secondary fault condition (over temperature, etc.) is detected. The LTC1154 logic and shutdown inputs are high impedance CMOS gates with ESD protection diodes to ground and supply and therefore should not be forced beyond the power supply rails. The shutdown pin should be connected to ground when not in use. ENABLE Input Pin The ENABLE input can be used to enable a number of LTC1154 high-side switches in banks or to provide a secondary means of control. It can also act as an inverting input. The ENABLE input is a high impedance CMOS gate with ESD clamp diodes to ground and supply and therefore should not be forced beyond the power supply rails. This pin should be grounded when not in use. Gate Drive Pin The gate drive pin is either driven to ground when the switch is turned OFF or driven above the supply rail when the switch is turned ON. This pin is a relatively high impedance when driven above the rail (the equivalent of a few hundred kΩ). Care should be taken to minimize any loading of this pin by parasitic resistance to ground or supply. Supply Pin The supply pin of the LTC1154 serves two vital purposes. The first is obvious: it powers the input, gate drive, regulation and protection circuitry. The second purpose is less obvious: it provides a Kelvin connection to the top of the drain sense resistor for the internal 100mV reference. The LTC1154 is designed to be continuously powered so that the gate of the MOSFET is actively driven at all times. If it is necessary to remove power from the supply pin and then re-apply it, the input pin (or enable pin) should be cycled a few milliseconds after the power is re-applied to reset the input latch and protection circuitry. Also, the input and enable pins should be isolated with 10k resistors to limit the current flowing through the ESD protection diodes to the supply pin. The supply pin of the LTC1154 should never be forced below ground as this may result in permanent damage to the device. A 300Ω resistor should be inserted in series with the ground pin if negative supply voltage transients are anticipated. 5 LTC1154 U U U PI FU CTIO S Drain Sense Pin The drain sense pin is compared against the supply pin voltage. If the voltage at this pin is more than 100mV below the supply pin, the input latch will be reset and the MOSFET gate will be quickly discharged. Cycle the input, or ENABLE input, to reset the short-circuit latch and turn the MOSFET back on. This pin is also a high impedance CMOS gate with ESD protection and therefore should not be forced beyond the power supply rails. To defeat the over current protection, short the drain sense to supply. Some loads, such as large supply capacitors, lamps, or motors require high in-rush currents. An RC time delay can be added between the sense resistor and the drain sense pin to ensure that the drain sense circuitry does not false-trigger during start-up. This time constant can be set from a few microseconds to many seconds. However, very long delays may put the MOSFET in risk of being destroyed by a short-circuit condition. (see Applications Information Section). Status Pin The status pin is an open-drain output which is driven low whenever a fault condition is detected. A 51k pull-up resistor should be connected between this output and a logic supply. The status pins of multiple LTC1154s can be OR’d together if independent fault sensing is not required. No connection is required to this pin when not in use. W BLOCK DIAGRA DRAIN SENSE ANALOG SECTION VS LOW STANDBY CURRENT REGULATOR SHUTDOWN TTL-TO-CMOS CONVERTER 10µs DELAY COMP 100mV REFERENCE SHUTDOWN GATE CHARGE AND DISCHARGE CONTROL LOGIC ANALOG GATE DIGITAL R INPUT ENABLE STATUS TTL-TO-CMOS CONVERTER VOLTAGE REGULATORS INPUT LATCH ONE SHOT S OSCILLATOR AND CHARGE PUMP FAST/SLOW GATE CHARGE LOGIC GND FAULT DETECTION AND STATUS OUTPUT DRIVER LTC1154 • BD01 6 LTC1154 TRUTH TABLE INPUTS OUTPUTS SWITCH CONDITION IN EN SD X H X L H SWITCH OFF L X X L H SWITCH OFF H L L H H SWITCH ON H L L L L SWITCH LATCHED OFF (OVER CURRENT) H L L L SWITCH LATCHED OFF (SHUTDOWN) L = LOGIC LOW H = LOGIC HIGH X = IRRELEVANT GATE STATUS = EDGE TRIGGERED LTC1154 OPERATIO The Truth Table demonstrates how the LTC1154 receives inputs and returns status information to the µP. The ENABLE and input signal from the µP controls the switch in its normal operating mode, where the rise and fall time of the gate drive are controlled to limit EMI and RFI emissions. The shutdown and over-current detection circuitry however, switch the gate off at a much higher rate to limit the exposure of the MOSFET switch and the load to dangerous conditions. The status pin remains high as long as the switch is operating normally, and is driven low only when a fault condition is detected. Note that the shutdown pin is edge-sensitive and latches the output off even if the shutdown pin returns to a low state. U The LTC1154 is a single micropower MOSFET driver with built-in protection, status feedback and gate charge pump. The LTC1154 consists of the following functional blocks: pump logic is not coupled into the 100mV reference or the analog comparator. Gate Charge Pump TTL and CMOS Compatible Inputs The LTC1154 input and shutdown input have been designed to accommodate a wide range of logic families. Both input thresholds are set at about 1.3V with approximately 100mV of hysteresis. A low standby current voltage regulator provides continuous bias for the TTL-to-CMOS converter. The TTL-toCMOS converter output enables the rest of the circuitry. In this way the power consumption is kept to a minimum in the standby mode. ENABLE Input The ENABLE input is CMOS compatible and inhibits the input signal whenever it is held logic high. This input should be grounded when not in use. Internal Voltage Regulation The output of the TTL-to-CMOS converter drives two regulated supplies which power the low voltage CMOS logic and analog blocks. The regulator outputs are isolated from each other so that the noise generated by the charge Gate drive for the MOSFET switch is produced by an adaptive charge pump circuit which generates a gate voltage substantially higher than the power supply voltage. The charge pump capacitors are included on chip and therefore no external components are required to generate the gate drive. Drain Current Sense The LTC1154 is configured to sense the current flowing into the drain of the power MOSFET in a high-side application. An internal 100mV reference is compared to the drop across a sense resistor (typically 0.002Ω to 0.10Ω) in series with the drain lead. If the drop across this resistor exceeds the internal 100mV threshold, the input latch is reset and the gate is quickly discharged via a large N-channel transistor. Controlled Gate Rise and Fall Times When the input is switched ON and OFF, the gate is charged by the internal charge pump and discharged in a controlled manner. The charge and discharge rates have 7 LTC1154 LTC1154 OPERATIO U been set to minimize RFI and EMI emissions in normal operation. If a short-circuit or current overload condition is encountered, the gate is discharged very quickly (typically a few microseconds) by a large N-channel transistor. gate of the MOSFET is driven low by the protection circuitry. The status circuitry is reset along with the input latch when the input, or ENABLE input, is cycled. Status Output Driver The status circuitry continuously monitors the fault detection logic. This open-drain output is driven low when the U W U UO APPLICATI S I FOR ATIO MOSFET and Load Protection The LTC1154 protects the power MOSFET switch by removing drive from the gate as soon as an over-current condition is detected. Resistive and inductive loads can be protected with no external time delay in series with the drain sense pin. Lamp loads, however, require that the over-current protection by delayed long enough to start the lamp but short enough to ensure the safety of the MOSFET. stored energy to ground. Many inductive loads have these diodes included. If not, a diode of the proper current rating should be connected across the load, as shown in Figure 2, to safely divert the stored energy. 12V + 100µF IN VS EN 0.036Ω DS LTC1154 STATUS Resistive Loads G IRFZ24 15V Loads that are primarily resistive should be protected with as short a delay as possible to minimize the amount of time that the MOSFET is subjected to an overload condition. The drain sense circuitry has a built-in delay of approximately 10µs to eliminate false triggering by power supply or load transient conditions. This delay is sufficient to “mask” short load current transients and the starting of a small capacitor (<1µF) in parallel with the load. The drain sense pin can therefore be connected directly to the drain current sense resistor as shown in Figure 1. GND SD CLOAD ≤ 1µF RLOAD 12Ω LTC1154 • F01 Figure 1. Protecting Resistive Loads 12V + 100µF Inductive Loads Loads that are primarily inductive, such as relays, solenoids and stepper motor windings should be protected with as short a delay as possible to minimize the amount of time that the MOSFET is subjected to an overload condition. The built-in 10µs delay will ensure that the overcurrent protection is not false-triggered by a supply or load transient. No external delay components are required as shown in Figure 2. Large inductive loads (>0.1mH) may require diodes connected directly across the inductor to safely divert the 8 IN VS EN 0.036Ω DS LTC1154 STATUS G IRFZ24 15V GND SD 1N5400 12V, 1A SOLENOID LTC1154 • F02 Figure 2. Protecting Inductive Loads LTC1154 W U U UO APPLICATI S I FOR ATIO Capacitive Loads Lamp Loads Large capacitive loads, such as complex electrical systems with large bypass capacitors, should be powered using the circuit shown in Figure 3. The gate drive to the power MOSFET is passed through an RC delay network, R1 and C1, which greatly reduces the turn-on ramp rate of the switch. And since the MOSFET source voltage follows the gate voltage, the load is powered smoothly and slowly from ground. This dramatically reduces the start-up current flowing into the supply capacitor(s) which, in turn, reduces supply transients and allows for slower activation of sensitive electrical loads. (Diode, D1, provides a direct path for the LTC1154 protection circuitry to quickly discharge the gate in the event of an over-current condition). The in-rush current created by a lamp during turn-on can be 10 to 20 times greater than the rated operating current. The circuit shown in Figure 4 shifts the current limit threshold up by a factor of 11:1 (to 30A) for 100ms when the bulb is first turned on. The current limit then drops down to 2.7A after the in-rush current has subsided. 12V + 470µF IN VS EN 10k 0.036Ω 100k DS VN2222LL LTC1154 STATUS G 0.1µF 1M GND 12V SD + 9.1V 470µF VS 0.036Ω CD 0.01µF EN DS D1 1N4148 LTC1154 STATUS GND G 12V/1A BULB RD 100k R1 100k LTC1154 • F04 Figure 4. Lamp Driver with Delayed Protection R2 100k MTP3055E SD C1 0.33µF OUT 15V + CLOAD 100µF LTC1154 • F03 Figure 3. Powering Large Capacitive Loads The RC network, RD and CD, in series with the drain sense input should be set to trip based on the expected characteristics of the load after start-up. With this circuit, it is possible to power a large capacitive load and still react quickly to an over-current condition. The ramp rate at the output of the switch as it lifts off ground is approximately: dV/dt = (VGATE – VTH)/(R1 × C1) And therefore the current flowing into the capacitor during start-up is approximately: ISTART-UP = CLOAD × dV/dt Using the values shown in Figure 3, the start-up current is less than 100mA and does not false-trigger the drain sense circuitry which is set at 2.7A with a 1ms delay. Selecting RD and CD Figure 5 is a graph of normalized over-current shutdown time versus normalized MOSFET current. This graph is used to select the two delay components, RD and CD, which make up a simple RC delay between the drain sense resistor and the drain sense input. 10 OVER-CURRENT SHUTDOWN TIME (1 = RC) IN MTP3055EL 1 0.1 0.01 1 10 100 MOSFET CURRENT (1 = SET CURRENT) LTC1154 • F05 Figure 5. Over-Current Shutdown Time vs MOSFET Current 9 LTC1154 W U U UO APPLICATI S I FOR ATIO The Y axis of the graph is normalized to one RC time constant. The X axis is normalized to the current. (The set current is defined as the current required to develop 100mV across the drain sense resistor). Note that the shutdown time is shorter for increasing levels of MOSFET current. This ensures that the total energy dissipated by the MOSFET is always within the bounds established by the manufacturer for safe operation. (See MOSFET data sheet for further information). 12V 5V + 120k 10k 10µF IN 5V µP OR CONTROL LOGIC VS 0.05Ω 10k EN DS LTC1154 10k STATUS MTP12N06 G 15V GND SD 10k LOAD 300Ω Using a Speed-Up Diode LTC1154 • F07 To reduce the amount of time that the power MOSFET is in a short-circuit condition, “bypass” the delay resistor with a small signal diode as shown in Figure 6. The diode will engage when the drop across the drain sense resistor exceeds about 0.7V, providing a direct path to the sense pin and dramatically reducing the amount of time the 12V VS EN DS 0.01µF 1N4148 0.036Ω 100k LTC1154 STATUS IRF530 G 15V GND Since the LTC1154 draws very little current while in normal operation, the drop across the ground resistor is minimal. The 5V µP (or control logic) is protected by the 10k resistors in series with the input and status pins. Current Limited Power Supplies + 100µF IN Figure 7. Reverse Battery Protection SD LOAD The LTC1154 requires at least 3.5V at the supply pin to ensure proper operation. It is therefore necessary that the supply to the LTC1154 be held higher than 3.5V at all times, even when the output of the switch is short circuited to ground. The output voltage of a current limited regulator may drop very quickly during short circuit and pull the supply pin of the LTC1154 below 3.5V before the shutdown circuitry has had time to respond and remove drive from the gate of the power MOSFET. A supply filter should LTC1154 • F06 Figure 6. Using a Speed-Up Diode >7V 5V/2A REGULATOR + MOSFET is in an overload condition. The drain sense resistor value is selected to limit the maximum DC current to 2.8A. The diode conducts when the drain current exceeds 20A and reduces the turn-off time to 15µs. VS EN DS The LTC1154 can be protected against reverse battery conditions by connecting a resistor in series with the ground lead as shown in Figure 7. The resistor limits the supply current to less than 50mA with – 12V applied. 10 47µF* 0.1µF 0.1Ω 10µF + IN 1N4148 100k LTC1154 STATUS Reverse Battery Protection + *20Ω 100µF GND IRLR024 G SHORT CIRCUIT SD *SUPPLY FILTER COMPONENTS LTC1154 • F08 Figure 8. Supply Filter for Current Limited Supplies LTC1154 W U U UO APPLICATI S I FOR ATIO be added as shown in Figure 8 which holds the supply pin of the LTC1154 high long enough for the over-current shutdown circuitry to respond and fully discharge the gate. Five volt linear regulators with small output capacitors are the most difficult to protect as they can “switch” from a voltage mode to a current limited mode very quickly. The large output capacitors on many switching regulators may be able to hold the supply pin of the LTC1154 above 3.5V sufficiently long that this extra filtering is not required. Because the LTC1154 is micropower in both the standby and ON state, the voltage drop across the supply filter is less than 2mV, and does not significantly alter the accuracy of the 100mV drain sense threshold voltage. UO TYPICAL APPLICATI S High-Side Driver with Over-Voltage Shutdown High-Side Driver with Thermal Shutdown 6V 5V 4.75V TO 5.25V 5V + + 100µF µP OR CONTROL LOGIC IN VS EN DS 10µF EN DS 5.6V LTC1154 STATUS† IRLZ24 G VS 100Ω µP OR CONTROL LOGIC LTC1154 STATUS† IN IRLD024 G 30k GND SD *RL3006-50-100-25-PT0 KEYSTONE GND PTC THERMISTOR (100°C)* SD 6V LOAD 5V LOAD SWITCH IS SHUTDOWN WHEN VS > 5.7V LTC1154 • TA03 †A LTC1154 • TA05 51k pullup resistor should be connected between Status Output and 5V Logic Supply. High-Side Driver with Under-Voltage Shutdown 5V 24V to 28V High-Side Switch with Thermal Shutdown 24V TO 28V + 100µF 1N4148* + 10k 100µF 3k + 1µF** 5V µP OR CONTROL LOGIC IN VS EN DS 2N2907 µP OR CONTROL LOGIC IRLZ24 G 18V 10µF VS IN LTC1154 STATUS† + 5V EN DS LTC1154 STATUS† MTP12N06 G 200k GND SD *OPTIONAL IF SUPPLY VOLTAGE LESS THAN 6V. **CAPACITOR CHARGED TO SUPPLY VOLTAGE. SHUTDOWN OCCURS WHEN SUPPLY VOLTAGE DROPS BY 0.6V. GND 10k SD 6V LOAD *KEYSTONE RL2006-100-100-30-PT. MOUNT ON MOSFET OR LOAD HEAT SINK PTC THERMISTOR (100°C)* 24V TO 28V LOAD LTC1154 • TA06 LTC1154 • TA04 11 LTC1154 UO TYPICAL APPLICATI S High-Side Relay Driver with Over-Current Protection and Status Feedback 24V to 28V Switch with Bootstrapped Supply 24V TO 28V 12V + 100µF 2Ω + 5V µP OR CONTROL LOGIC 18V IN VS EN DS STATUS 6.2k µP OR CONTROL LOGIC 1N4148 VS EN DS 10k 0.01µF STATUS G 15V SD *KEYSTONE RL2006-100-100-30-PT. MOUNT ON MOSFET OR LOAD HEAT SINK. I Q(OFF) = 60µA, IQ(ON) = 1mA. †A 1N4148 MTD3055E LTC1154 † MTP15N06E G IN 200k GND GND PTC THERMISTOR (100°C)* 1N4001 24V TO 28V LOAD COIL CURRENT LIMITED TO 350mA. CONTACT CURRENT LIMITED TO 5A. LTC1154 • TA07 LTC1154 • TA08 “4-Cell-to-5V” Extremely Low Voltage Drop Regulator with Over-Current Shutdown, Status Feedback, Ramped Turn-ON and 8µA Standby Current 4-CELL BATTERY PACK + 100µF 0.036Ω 5V IN VS EN DS LTC1154 STATUS† 200pF 100k 100k G SD IRLR024 1N4148 0.22µF GND 10k 8 7 1 3 LT1431 6 5 4 5V/2A + 470µF ESR < 0.5Ω LTC1154 • TA09 12 TO 12V LOAD SD 51k pullup resistor should be connected between Status Output and 5V Logic Supply. µP OR CONTROL LOGIC 0.02Ω 5V 10µF LTC1154 † + 100k 100µF LTC1154 UO TYPICAL APPLICATI S Bank Controlled High-Side Switches with “Global” Thermal and Over-Voltage Shutdown 12V IN VS 100Ω EN + 470µF DS LTC1154 STATUS G IRLR024 15V GND SD IN VS OUTPUT 1 5V EN DS LTC1154 51k STATUS G IRLR024 15V µP OR CONTROL LOGIC GND SD IN VS EN OUTPUT 2 DS LTC1154 STATUS G IRLR024 15V GND SD IN VS EN DS OUTPUT 3 120k LTC1154 STATUS G IRLR024 15V GND SD OUTPUT 4 15V *KEYSTONE RL2006-100-100-30-PT. MOUNT ON COMMON HEAT SINK. PTC THERMISTOR (100°C)* LTC1154 • TA10 13 LTC1154 UO TYPICAL APPLICATI S 12V Step-Up Regulator with Ultra-Low Standby Current, Over-Current Protection and Status Feedback 0.02Ω 5V + 330µF + 47µF IN VS EN DS 10k 5 + 1N4148 VIN 150µF 1N4148 3 LTC1154 STATUS STATUS 100k 1 1.24k 1% 100k G GND 10.72k 1% 4 VSW LT1070 2 FB VC GND 0.22µF 51k 12V/1A + 20Ω 470µF ON/OFF 1N5820 50µH IRLZ24 1k 0.1µF SD 1µF LTC1154 • TA11 12V Step-Up Regulator with 1A Over-Current Protection, Switch Status Feedback and Ramped Output 50µH 1N5820 5V + + 150µF 330µF 0.1Ω 5 1N4148 VIN 4 VSW LT1070 2 FB VC GND 3 1 1k 10.72k 1% ON/OFF IN VS 10k 0.1µF 51k 1.24k 1% EN DS LTC1154 STATUS STATUS 1N4148 100k 100k G IRF530 12V 1µF GND SD + 0.22µF 12V/1A 47µF LTC1154 • TA12 14 LTC1154 UO TYPICAL APPLICATI S Auto-Reset High-Side Switch with Over-Current and Over-Current Temperature Shutdown 12V + RT 1M** 100µF 1M 0.036Ω ON/OFF IN VS EN + DS LTC1154 CT 100µF** STATUS MTP12N06 G VN2222LL 18V 200k GND SD PTC THERMISTOR (100°C)* *KEYSTONE RL2006-100-100-30-PT. **AUTO-RESET PERIOD ≈ 800ms WITH COMPONENTS SHOWN 12V LOAD LTC1154 • TA13 SCSI Termination Power Switch with 1A Over-Current Shutdown, Auto-Reset and Load Soft-Start 0.1Ω MTD3055EL 1N5817 4.25V/1A 5V + 1M 100µF 1M ON/OFF + IN 0.1µF DS LTC1154 + STATUS 1µF 1N4148 47µF 1N4148 100k 100k G VN2222LL GND 10k + VS EN 10µF 20Ω SD 0.22µF LTC1154 • TA14 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of circuits as described herein will not infringe on existing patent rights. 15 LTC1154 U PACKAGE DESCRIPTIO N8 Package 8-Lead Plastic Lead 0.300 – 0.320 (7.620 – 8.128) 0.045 – 0.065 (1.143 – 1.651) 0.400 (10.160) MAX 0.130 ± 0.005 (3.302 ± 0.127) 8 +0.025 0.325 –0.015 8.255 +0.635 –0.381 6 5 0.065 (1.651) TYP 0.009 – 0.015 (0.229 – 0.381) ( 7 0.045 ± 0.015 (1.143 ± 0.381) ) 0.100 ± 0.010 (2.540 ± 0.254) 0.125 (3.175) MIN 0.250 ± 0.010 (6.350 ± 0.254) 0.020 (0.508) MIN 1 2 4 3 0.018 ± 0.003 (0.457 ± 0.076) S8 Package 8-Lead Plastic SOIC 0.010 – 0.020 × 45° (0.254 – 0.508) 0.016 – 0.050 0.406 – 1.270 8 0.004 – 0.010 (0.101 – 0.254) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 0.189 – 0.197 (4.801 – 5.004) 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) BSC 16 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977 6 5 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157 (3.810 – 3.988) 1 Linear Technology Corporation 7 2 3 4 LT/GP 1192 10K REV 0 LINEAR TECHNOLOGY CORPORATION 1992