MIC2546/2547 Micrel MIC2546/2547 Dual Programmable Current Limit Switch Preliminary Information General Description Features The MIC2546 and MIC2547 are integrated high-side dual power switches optimized for low loss dc power switching and other power management applications, including Advanced Configuration and Power Interface (ACPI). The MIC2546/47 is a cost-effective, highly integrated solution that requires few external components to satisfy USB and ACPI requirements. Load current management features include a precision resistor-programmable output current-limit and a soft-start circuit which minimizes inrush current when the switch is enabled. Thermal shutdown, along with current-limit, protects the switch and the attached device. The MIC2546/47’s open-drain flag outputs are used to indicate current-limiting or thermal shutdown to a local controller. The MIC2547 has an additional internal latch which turns the output off upon thermal shutdown providing robust fault control. The enable signal is compatible with both 3V and 5V logic, and is also used as the thermal shutdown latch reset for the MIC2547. The MIC2546 and MIC2547 are available in active-high and active-low enable versions in 16-pin TSSOP and SOP packages. • • • • • • • • • • • 2.7V to 5.5V input Adjustable current-limit up to 1.5A Reverse current flow blocking (no “body diode”) 100µA typical on-state supply current per channel 2µA typical off-state supply current 120mΩ maximum on-resistance Open-drain fault flag Thermal shutdown Thermal shutdown output latch (MIC2547) 2ms (slow) turn-on and fast turnoff Available with active-high or active-low enable Applications • • • • • • • USB power distribution PCI Bus Power Switching Notebook PC ACPI power distribution PC card hot swap applications Inrush current-limiting Ideal for dual supply applications Typical Application +5V 0.1µF RFLGA MIC2546-xBM On/Off ENA RSETA RFLGB On/Off FLGA INA GNDA OUTA ILIMA NC ENB Peripheral OUTA 33µF OUTB FLGB INB GNDB OUTB ILIMB NC Peripheral 33µF RSETB +3.3V 0.1µF Typical Advanced Configuration and Power Interface (ACPI) Application Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com June 2000 1 MIC2546/2547 MIC2546/2547 Micrel Ordering Information Part Number Enable Temperature Range Package MIC2546-1BM Active High Latch* –40°C to +85°C 16-pin SOP MIC2546-1BTS Active High –40°C to +85°C 16-pin TSSOP MIC2546-2BM Active Low –40°C to +85°C 16-pin SOP MIC2546-2BTS Active Low –40°C to +85°C 16-pin TSSOP MIC2547-1BM Active High • –40°C to +85°C 16-pin SOP MIC2547-1BTS Active High • –40°C to +85°C 16-pin TSSOP MIC2547-2BM Active Low • –40°C to +85°C 16-pin SOP MIC2547-2BTS Active Low • –40°C to +85°C 16-pin TSSOP * Thermal Shutdown Latch Pin Configuration MIC2546/2547 MIC2546/2547 INA 1 16 OUTA (ENA) (FLGA) OUTA 2 15 ILIMA (ILIMA) ENA 3 14 GNDA NC 4 13 FLGB (ENB) (FLGB) FLGA 5 12 ENB GNDB 6 11 OUTB ILIMB 7 10 NC OUTB 8 9 INB LOGIC, CHARGE PUMP (OUTA) (INA) LOGIC, CHARGE PUMP (OUTB) (INB) (ILIMB) (GND) Functional Pinout 16-Pin SOP (M) 16-Pin TSSOP (TS) Pin Description Pin Number Pin Name 1 INA 2, 16 OUTA 3 ENA 4, 10 NC 5 FLGA 6, 14 GNDB, GNDA 7 ILIMB Current Limit Channel B: Sets current-limit threshold using an external resistor, RSET, connected to ground. 154Ω < RSET < 2.29kΩ. 8, 11 OUTB Switch B (Output): Pins 8 and 11 must be externally connected. 9 INB Input B 12 ENB Enable B (Input) 13 FLGB Fault Flag B (Output) 15 ILIMA Current Limit Channel A. MIC2546/2547 Pin Function Input A: Output A MOSFET drain. Also supplies internal circuitry. Switch A (Output): Output A MOSFET source. Pins 2 and 16 must be externally connected. Enable A (Input): Logic-compatible enable input. Active-high (–1) or activelow (–2). High input >1.7V typical; low input <1.5V typical. Do not float. MIC2547 only: Also resets thermal shutdown latch. Not internally connected. Fault Flag A (Output): Active-low, open-drain output. Indicates overcurrent or thermal shutdown conditions. MIC2547 only: latched low on thermal shutdown. Ground. Both pins must be connected to GND. 2 June 2000 MIC2546/2547 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIN) .................................................. +6.0V Output Voltage (VOUT) ............................................... +6.0V Output Current (IOUT) ............................... Internally Limited Enable Input (VEN) ................................ –0.3V to VIN +0.3V Fault Flag Voltage (VFLG) ........................................... +6.0V Fault Flag Current (IFLG) ............................................ 50mA Storage Temperature (TS) ....................... –65°C to +150°C Junction Temperature (TJ) ....................... Internally Limited Lead Temperature (soldering 5 sec.) ........................ 260°C ESD Rating, Note 3 ...................................................... 2kV Supply Voltage (VIN) ................................... +2.7V to +5.5V Current Limit Set Range ..................................... 0.1 to 1.5A Ambient Temperature Range (TA) ............. –40°C to +85°C Package Thermal Resistance SOP (θJA) .......................................................... 120°C/W TSSOP (θJA) ..................................................... 100°C/W Electrical Characteristics VIN = +5V; TA = 25°C, bold indicates –40°C to +85°C; unless noted Symbol VEN Parameter Condition Supply Current Enable Input Voltage Min Typ Max Units Switch off, OUT = open, Note 4 1.5 10 µA Switch on, OUT = open, Note 4 200 320 µA Enable High, Note 4 Enable Input Current 2.4 1.7 V Enable Low, Note 4 1.5 0.8 V VEN = VOH(min) = 2.4V .01 1 µA VEN = VOL(max) = 0.8V .01 1 µA Enable Input Capacitance Note 5 1 Switch Resistance IOUT = 500mA 80 120 mΩ Current Limit Factor, Note 6 IOUT = 100mA to 1.5A, VOUT = 1.0V to 4.0V, Note 6 230 276 V Output Leakage Current Switch off 1 10 µA tON Output Turn-On Delay RL = 10Ω, CL = 1µF, Figure 1a and 1b 1 2 5 ms tR Output Turn-On Rise Time RL = 10Ω, CL = 1µF, Figure 1a and 1b 1 2 5 ms tOFF Output Turnoff Delay RL = 10Ω, CL = 1µF, Figure 1a and 1b 22 µs tF Output Turnoff Fall Time RL = 10Ω, CL = 1µF, Figure 1a and 1b 21 µs Overtemperature Threshold TJ increasing 140 °C Shutdown TJ decreasing 130 °C Error Flag Output Resistance VIN = 5V, IL = 10µA 4 15 Ω VIN = 3.3V, IL = 10µA 5 20 Ω 0.01 1 µA RDS(on) 184 pF Error Flag Off Current VFLG = 5V EN Pulse Reset Width MIC2547 Thermal Shutdown Latch 5 µs VIN to EN Set-Up MIC2547, Note 5 0 µs Current-Limit Response Time VOUT = 0V 25 µs Overcurrent FLG Response Time VOUT = VIN/2 to FLG low 5 µs Note 1. Exceeding the absolute maximum rating may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. Note 4. Off is ≤ 0.8V and on is ≥ 2.4V for the MIC2546-1 and MIC2547-1. Off is ≥ 2.4V and on is ≤ 0.8V for the MIC2546-2 and MIC2547-2. The enable input has about 200mV of hysteresis. Note 5. Guaranteed by design, but not production tested. Note 6. Current limit threshold is determined by: ILIMIT June 2000 = 230V RSET , where RSET is in ohms. 3 MIC2546/2547 MIC2546/2547 Micrel Typical Characteristics Output On-Resistance vs. Supply Voltage Output On-Resistance vs. Temperature 80 TA = 27°C 70 60 100 3.3V 80 5.0V 60 5.5 200 160 3.3V 80 160 120 80 40 0 2.5 2.7V 0.6 0.5 5.0V 0.4 0.3 3.3V 0.2 0.1 2.7V 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Enable Threshold Voltage vs. Supply Voltage Enable Threshold Voltage vs. Temperature 0.18 0.16 0.08 0.06 0.04 0.02 1.5 1.4 VEN FALLING 1.3 1.2 1.1 1.0 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) VEN RISING 1.6 VEN FALLING 1.2 1.0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 5.5 Output Fall Time vs. Temperature 2000 2.5 1.0 3.3V 5.0V 0.5 CURRENT LIMIT (mA) 1.5 2.7V VIN = 5V 1000 ISET ITH ISHORT 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) MIC2546/2547 0 100 1000 RSET (Ω) 4 2.7V 5 3.3V 4 3 5.0V 2 1 RL = 44Ω Output Current vs. Output Voltage 2000 1500 500 6 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Current Limit vs. RSET RL = 44Ω 2.0 5.5 7 1.8 1.4 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) Rise Time vs. Temperature OUTPUT RISE TIME (ms) VEN RISING 1.7 1.6 TA = 27°C 0.14 0.12 0.1 0 2.5 OUTPUT CURRENT (mA) TA = 27°C 5.5 Off-State Supply Current vs. Supply Voltage 2.0 1.9 1.8 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 0.20 RL = 44Ω 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 2.0 ENABLE THRESHOLD (V) SUPPLY CURRENT (µA) 240 0.7 ENABLE THRESHOLD (V) SUPPLY CURRENT (µA) 0.8 40 TA = 27°C 200 Off-State Supply Current vs. Temperature 280 5.0V 240 40 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) On-State Supply Current vs. Temperature 120 2.7V SUPPLY CURRENT (µA) 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 280 SUPPLY CURRENT (mA) 90 50 2.5 OUTPUT FALL TIME (µs) On-State Supply Current vs. Supply Voltage 120 ON-RESISTANCE (mΩ) ON-RESISTANCE (mΩ) 100 5000 RSET = 150 1500 VIN = 5V 1000 RSET = 470 500 RSET = 2.3k 0 0 1 2 3 4 5 OUTPUT VOLTAGE (V) 6 June 2000 MIC2546/2547 Micrel Current Limit vs. Temperature Current Limit vs. Supply Voltage 1100 ITH ITH 1000 900 VIN = 5V RSET = 230Ω ISET 800 700 ISHORT 600 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) June 2000 CURRENT LIMIT (mA) OUTPUT CURRENT (mA) 1100 1000 900 ISET TA = 27°C RL = 230Ω 800 700 600 2.5 ISHORT 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5 5.5 MIC2546/2547 MIC2546/2547 Micrel Functional Characteristics VOUT VFLG VEN (2V/div.) (5V/div.) (10V/div.) Turnoff Response VIN = 5V CIN = 4.7µF VIN = 5V CIN = 4.7µF CL = 1µF RL = 10Ω MIC2546-1 MIC2546-1 TIME (1ms/div.) TIME (500µs/div.) VOUT VFLG VEN (5V/div.) (10V/div.) (10V/div.) Enable Into Heavy Load Thermal Shutdown VIN = 5V CIN = 4.7µF RL = 1Ω ISET = 1A ISET = 1A RL = 1Ω MIC2546-1 MIC2546-1 TIME (100ms/div.) TIME (100ms/div.) Enable Into Heavy Load Inrush Current Response VOUT (5V/div.) VIN = 5V CIN = 4.7µF RL = 1Ω ISET = 1A VFLG VEN (5V/div.) (10V/div.) VFLG VEN (5V/div.) (10V/div.) VIN = 5V CIN = 4.7µF IOUT (500mA/div.) IOUT (500mA/div.) VOUT VFLG VEN (5V/div.) (10V/div.) (10V/div.) Current-Limit Response Reset VIN = 5V CIN = 4.7µF RL = 10Ω Output Latched IOUT (500mA/div.) CL = 110µF IOUT (1A/div.) Thermal Shutdown MIC2547-1 CL = 60µF CL = 10µF MIC2546-1 TIME (500µs/div.) MIC2546/2547 CL = 1µF RL = 10Ω IOUT (200mA/div.) IOUT (200mA/div.) VOUT (2V/div.) VFLG VEN (10V/div.) (5V/div.) Turn-On Response TIME (500µs/div.) 6 June 2000 MIC2546/2547 Micrel Test Circuit VOUT Device Under OUT Test IOUT RL CL tr tf 90% 90% VOUT 10% 10% Functional Characteristics Test Circuit Timing Diagrams VEN 50% tOFF tON 90% VOUT 10% Figure 1a. MIC2546/47-1 VEN 50% tOFF tON VOUT 90% 10% Figure 1b. MIC2546/47-2 June 2000 7 MIC2546/2547 MIC2546/2547 Micrel Output Reset EN Short-Circuit Fault VOUT ILIMIT IDC IOUT Fault Removed Thermal Shutdown Reached FLG Figure 2a. MIC2547-2 Timing: Output is reset by toggling EN EN Short-Circuit Fault Fault Removed VOUT ILIMIT IDC IOUT Thermal Shutdown Reached FLG Figure 2b. MIC2546-2 Timing MIC2546/2547 8 June 2000 MIC2546/2547 Micrel Block Diagram ENA OSC. THERMAL SHUTDOWN 1.2V REFERENCE CHARGE PUMP GATE CONTROL RESET CURRENT LIMIT THERMAL SHUTDOWN LATCH (MIC2547) INA ILIMA RSETA OUTA FLGA ENB OSC. THERMAL SHUTDOWN 1.2V REFERENCE CHARGE PUMP GATE CONTROL RESET THERMAL SHUTDOWN LATCH (MIC2547) ILIMB RSETB OUTB FLGB GNDB June 2000 CURRENT LIMIT INB 9 GNDA MIC2546/2547 MIC2546/2547 Micrel Adjustable Current-Limit The short-circuit current-limit is user-adjustable with an external set resistor. Current-limit in the range of 100mA to 1.5A is available with a set point accuracy of better than ±20%. The current-limit circuit prevents damage to the output MOSFET and external load. The nominal current-limit value is set with an external resistor between ILIMX and GND. For a desired current-limit, the value of the external set resistor is given by: Functional Description The MIC2546 and MIC2547 are dual high-side N-channel switches available with active-high or active-low enable inputs. Fault conditions turn off or inhibit turn-on of the output transistor and activate the open-drain error flag transistor making it sink current to ground. Input and Output INX is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUTX is the source of the output MOSFET. In a typical circuit, current flows from INX to OUTX toward the load. If VOUT is greater than VIN, current will flow from OUTX to INX since the switch is bidirectional when enabled. The output MOSFET and driver circuitry are also designed to allow the MOSFET source to be externally forced to a higher voltage than the drain (VOUT > VIN) when the switch is disabled. In this situation, the MIC2546/47 avoids undesirable current flow from OUTX to INX. Both OUT pins for a given channel must be connected together. Thermal Shutdown Thermal shutdown shuts off the output MOSFET and signals the fault flag if the die temperature exceeds 140°C. 10°C of hysteresis prevents the switch from turning on until the die temperature drops to 130°C. Overtemperature detection functions only when the switch is enabled. The MIC2547 features an internal latch which causes the part to remain off after thermal shutdown until a reset pulse is provided via the enable pin. While in current-limit, the thermal shutdown latch prevents on/off cycling of the output. Refer to Figure 2 for timing diagram. The flag remains low until reset. Enable Input ENX must be driven logic high or logic low, or be pulled high or low for a clearly defined input. Floating the input may cause unpredictable operation. ENX should not be allowed to go negative with respect to GND, and VENX should be less than or equal to VINX. MIC2546/2547 230V RSETX = ILIMITX where: 154Ω < RSET < 2.29kΩ For example, to set a 1A nominal current-limit, RSET is calculated as: 230V 1A = 230Ω Current through RSETX increases with OUT current. The voltage across RSETX could be monitored with a high impedance comparator to provide an indication of output current. RSETX should be between 154Ω and 2.29kΩ (0.5% resistor value). Short-Circuit Protection In the event of a short-circuit, the output current will fold back to approximately 80% of the short-circuit current-limit. Fault Flag FLGX is an N-channel, open-drain MOSFET output. The fault-flag is active (low) for current-limit or thermal shutdown conditions. The flag output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. 10 June 2000 MIC2546/2547 Micrel PD = RDS(on) × (IOUT)2 To relate this to junction temperature, the following equation can be used: Tj = PD × θJA + TA where: Tj = junction temperature TA = ambient temperature θJA = is the thermal resistance of the package Applications Information Supply Filtering A 0.1µF to 1µF bypass capacitor from INX to GND, located near the MIC2546 and MIC2547, is strongly recommended to control supply transients. Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance) to damage internal control circuitry. Input transients must not exceed the absolute maximum supply voltage (VIN max = 6V) even for a short duration. Transient Overcurrent Filter The inrush current from the connection of a heavy capacitive load may cause the fault flag to fall for 10µs to 200µs while the switch is in a constant-current mode, charging the capacitance. Adding an optional series resistor-capacitor (RSET2) in parallel with RSET, as shown in Figure 3, allows the transient current-limit to be set to a different value than steady state. A typical USB hot-plug inrush is 2A to 3A for 10µs to 20µs. If RSET is 435Ω (510mA), an RSET2 of 88Ω (2.5A) and CSET of 1µF (RC = 100µs) allows transient surge of 3A to pass for 100µs without tripping the overcurrent flag (FLG). USB Power Distribution The MIC2546 is ideal for meeting USB power distribution requirements. Figure 3 depicts a USB Host application. RSET should be set to a value providing a current-limit >500mA. The accurate current-limit of the MIC2546 will reduce power supply current requirements. Also, fast reaction to short circuit faults prevent voltage droop in mobile PC applications. Printed Circuit Board Hot-Plug The MIC2546/47 are ideal inrush current-limiters suitable for hot-plug applications. Due to the integrated charge pump, the MIC2546/47 presents a high impedance when off and slowly becomes a low impedance as it turns on. This “softstart” feature effectively isolates power supplies from highly capacitive loads by reducing inrush current during hot-plug events. 4.0V to 5.5V MIC2546-1BM 1 0.1 to 1µF 2 3 4 5 INA OUTA OUTA ILIMA ENA GNDA NC FLGB FLGA 6 ENB GNDB OUTB 7 8 ILIMB NC OUTB INB 16 15 14 13 12 11 10 RSETA . 9 0.1 to 1µF RSETB Supply Bypassing Power Dissipation The device's junction temperature depends on several factors such as the load, PCB layout, ambient temperature and package type. Equations that can be used to calculate power dissipation and junction temperature are found below. Calculation of power dissipation can be accomplished by the following equation: (+) 5V 10k 4.7µF 10k MIC5203-3.3 LDO Regulator 3.3V USB Controller (–) VBUS D+ 100k 1.5k 2% IN D– OUT GND 100k V+ VBUS INA ON/OFF OUTA OUTA ILIMA OVERCURRENT GND ENA GNDA NC FLGB FLGA D+ D– Ferrite Bead MIC2546-2BM 0.01µF 120µF ENB ILIMB NC OUTB INB Bold lines indicate 0.1" wide, 1-oz. copper high-current traces. D– GND Downstream USB Port 1 4.75V min. 500mA max. VBUS GNDB OUTB RSET GND D+ RSET D+ 0.01µF 120µF D– GND Downstream USB Port 2 4.75V min. 500mA max. Ferrite Bead RSET(2) CSET (optional) Figure 3. USB Host Application June 2000 11 MIC2546/2547 MIC2546/2547 Micrel Package Information PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) REF 0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102) 0.050 (1.27) BSC 0.0648 (1.646) 0.0434 (1.102) 0.394 (10.00) 0.386 (9.80) 45° 0°–8° 0.050 (1.27) 0.016 (0.40) SEATING PLANE 0.244 (6.20) 0.228 (5.79) 16-Pin SOP (M) DIMENSIONS: MM (INCH) 4.50 (0.177) 6.4 BSC (0.252) 4.30 (0.169) 0.30 (0.012) 0.19 (0.007) 7.90 (0.311) 7.70 (0.303) 0.65 BSC (0.026) 1.10 MAX (0.043) 0.20 (0.008) 0.09 (0.003) 1.00 (0.039) REF 8° 0° 0.15 (0.006) 0.05 (0.002) 0.70 (0.028) 0.50 (0.020) 16-Pin TSSOP (TS) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated MIC2546/2547 12 June 2000