LTC1710CS8

LTC1710 SMBus Dual Monolithic High Side Switch U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTION Two 0.4Ω/300mA N-Channel Switches Available in MS8 and SO-8 Packages SMBus and I2C Compatible 0.6V VIL and 1.4V VIH for DATA and CLK Low Standby Current: 14µA Separate Drain Connection to SW0 Three Addresses from One Three-State Address Pin Independent Control of Up to Six Switches Built-In Power-On Reset Timer Built-In Undervoltage Lockout U APPLICATIONS ■ ■ ■ ■ ■ Using the 2-wire interface, CLK and DATA, the LTC1710 follows SMBus’s Send Byte Protocol to independently control the two 0.4Ω internal N-channel power switches, which are fully enhanced by onboard charge pumps. The LTC1710 has one three-state programmable address pin that allows three different addresses for a total of six available switches on the same bus. The LTC1710 also features a separate user-controlled drain supply (SW0D) to Switch 0 so that it can be used to control SMBus peripherials using a different power supply. Handheld Computer Power Management Computer Peripheral Control Laptop Computer Power Plane Switching Portable Equipment Power Control Industrial Control Systems ACPI SMBus Interface , LTC and LT are registered trademarks of Linear Technology Corporation. U ■ The LTC®1710 SMBus dual switch has two built-in 0.4Ω/ 300mA switches that are controlled by a 2-wire SMBus interface. With a low standby current of 14µA (3.3V), the LTC1710 operates over an input voltage range of 2.7V to 5.5V while maintaining the SMBus specified 0.6V VIL and 1.4V VIH input thresholds. TYPICAL APPLICATION Switch Voltage Drop vs Load Current VCC 2.7V TO 5.5V SW0D 0V TO VCC 1 10µF SW0 CLOCK FROM SMBus DATA AD1 (PROGRAMMABLE) 5 6 2 LOAD 1 CHARGE PUMP 3 7 SW1 SWITCH VOLTAGE DROP (mV) 8 10µF 500 TA = 25°C 400 300 200 VCC = 2.7V VCC = 3.3V 100 VCC = 5V LOAD 2 LTC1710 0 4 1710 TA01 0 200 100 300 LOAD CURRENT (mA) 400 1710 TA02 1 LTC1710 U W W W ABSOLUTE MAXIMUM RATINGS (Voltages Referred to GND Pin) (Note 1) Input Supply Voltage (VCC) .......................... – 0.3V to 6V Input Supply Voltage (VCC) with SW0 Connected as a Low Side Switch ........................... – 0.3V to 3.6V DATA, CLK (Bus Pins 6, 5)......................... – 0.3V to 6V* AD1 ( Address Pin 3) ....................... – 0.3V to VCC + 0.3V OUT0, OUT1 (Output Pins 2, 7) ................... – 0.3V to 6V SW0D (Switch 0 Drain Pin 1)....................... – 0.3V to 6V OUT0, OUT1 (Output Pins 2, 7) Continuous .................................................... 300mA Pulsed, < 10µs (nonrepetitive) ............................... 1A Operating Temperature Range LTC1710C................................................ 0°C to 70°C LTC1710I ............................................ – 40°C to 85°C Junction Temperature** ...................................... 125°C Storage Temperature Range .................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C *Supply rails to DATA and CLK are independent of VCC to LTC1710. **Although the LTC1710 can sustain TJMAX = 125°C without damage, its internal protection circuitry is set to shut down the switches at TJ = 120°C with 15°C hysteresis. W U U PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW SW0D OUT0 AD1 GND 1 2 3 4 8 7 6 5 VCC OUT1 DATA CLK MS8 PACKAGE 8-LEAD PLASTIC MSOP LTC1710CMS8 MS8 PART MARKING TJMAX = 110°C, θJA = 150°C/ W ORDER PART NUMBER TOP VIEW SW0D 1 8 VCC OUT0 2 7 OUT1 AD1 3 6 DATA GND 4 5 CLK LTC1710CS8 LTC1710IS8 S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO LTDZ 1710 1710I TJMAX = 110°C, θJA = 110°C/ W Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VCC Operating Supply Voltage Range IVCC Supply Current RDS(ON) Power Switch On Resistance TA = 25°C, VCC = SW0D = 5V unless otherwise noted. CONDITIONS ● TYP 2.7 MAX UNITS 5.5 V Charge Pump Off, AD1 High or Low, DATA and CLK High VCC = 5V VCC = 3.3V VCC = 2.7V ● ● ● 17 14 11 30 30 30 µA µA µA OUT0 or OUT1 High (Command Byte XXXXXX01 or XXXXXX10) Both Outputs High (Command Byte XXXXXX11) ● ● 200 250 300 500 µA µA 0.55 0.46 0.40 0.7 0.6 Ω Ω Ω VCC = 2.7V, IOUT = 300mA VCC = 3.3V, IOUT = 300mA VCC = 5V, IOUT = 300mA VUVLO Undervoltage Lockout Falling Edge (Note 2) tPOR Power-On Reset Delay Time VCC = 2.7V (Note 3) VCC = 5.5V fOSC Charge Pump Oscillator Frequency (Note 3) 2 MIN ● 1.5 2.0 2.5 V 300 300 1000 1000 µs µs 300 kHz LTC1710 ELECTRICAL CHARACTERISTICS TA = 25°C, VCC = SW0D = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS tON Output Turn-On Time (100Ω/1µF Load) VCC = 2.7V (From ON (Note 6) to VOUT = 90% VCC) VCC = 5.5V (From ON (Note 6) to VOUT = 90% VCC) 200 160 µs µs tOFF Output Turn-Off Time (100Ω/1µF Load) VCC = 2.7V (From OFF (Note 7) to VOUT = 10% VCC) VCC = 5.5V (From OFF (Note 7) to VOUT = 10% VCC) 250 250 µs µs VIL DATA/CLK Input Low Voltage AD1 Input Low Voltage VCC = 2.7V to 5.5V VCC = 2.7V to 5.5V ● ● VIH DATA/CLK High Voltage AD1 Input High Voltage VCC = 2.7V to 5.5V VCC = 2.7V to 5.5V ● ● VOL Data Output Low Voltage VCC = 2.7V to 5.5V, IPULL-UP = 350µA ● CIN Input Capacitance (DATA, CLK, AD1) IIN Input Leakage Current (DATA, CLK) ● ±1 µA Input Leakage Current (AD1) ● ±250 nA 100 kHz 0.6 0.2 V V 1.4 VCC – 0.2 V V 0.18 0.4 V 5 pF SMBus Related Specifications (Note 5) fSMB SMBus Operating Frequency 10 tBUF Bus Free Time Between Stop and Start 4.7 µs tSU:STA Start Condition Setup Time 4.7 µs tHD:STA Start Condition Hold Time 4.0 µs tSU:STO Stop Condition Setup Time 4.0 µs tHD: DAT Data Hold Time 300 ns tSU:DAT Data Setup Time 250 ns tLOW Clock Low Period 4.7 tHIGH Clock High Period 4.0 tf Clock/Data Fall Time 300 ns tr Clock/Data Rise Time 1000 ns IPULL-UP Current Through External Pull-Up Resistor on DATA Pin 350 µA VCC = 2.7V to 5.5V (Open-Drain Data Pull-Down Current Capacity) The ● denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Approximately 3% hysteresis is provided to ensure stable operation and eliminate false triggering by minor VCC glitches. Note 3: Measured from VCC > VUVLO to SMBus ready for DATA input. 100 µs µs 50 Note 4: The oscillator frequency is not tested directly but is inferred from turn-on time. Note 5: SMBus timing specifications are guaranteed but not tested. Note 6: ON is enabled upon receiving the Stop condition from the SMBus master. Note 7: OFF is enabled upon receiving the Stop condition from the SMBus master. 3 LTC1710 U W TYPICAL PERFOR A CE CHARACTERISTICS Supply Current (IQ) vs Supply Voltage Supply Current (IQ) vs Temperature Standby Current vs Temperature 50 500 500 TA = 25°C 40 400 30 VCC = 3.3V VCC = 5V 10 BOTH SW ON 200 SW1 ON SW0 ON 50 0 TEMPERATURE (°C) 50 0 TEMPERATURE (°C) IOUT = 300mA 0.6 0.5 400 IPULL-UP = 350µA 0.8 SWITCH RDS(ON) (Ω) SWITCH RDS(ON) (Ω) 0.8 Data ACK VOL vs Temperature IOUT = 300mA 0.9 VCC = 2.7V VCC = 3.3V VCC = 5V 0.4 0.3 0.4 VCC = 5V 0.3 0.1 100 VCC = 3.3V 0.5 0.1 0 50 TEMPERATURE (°C) VCC = 2.7V 0.6 0.2 0 – 50 300 0.7 0.2 0 8 1710 G03 Switch RDS(ON) vs Temperature (MSOP Package) 1.0 0.7 2 4 6 SUPPLY VOLTAGE (V) 0 1710 G02 Switch RDS(ON) vs Temperature (SO-8 Package) 0.9 SW1 ON SW0 ON 200 100 1710 G01 1.0 BOTH SW ON 0 0 – 50 100 300 100 100 VCC = 2.7V 0 – 50 300 DATA ACK VOL (mV) 20 SUPPLY CURRENT (µA) 400 SUPPLY CURRENT (µA) STANDBY CURRENT (µA) VCC = 5V 200 100 0 20 60 40 TEMPERATURE (°C) 1710 G04 80 100 1710 G05 0 – 50 0 50 TEMPERATURE (°C) 100 1710 G06 U U U PIN FUNCTIONS SW0D (Pin 1): Drain Supply of Switch 0. User-programmable from 0V to VCC. OUT0 (Pin 2): Source Output of Switch 0. Maximum load of 300mA; controlled by LSB of command byte. AD1 (Pin 3): Three-State Programmable Address Pin. Must be connected directly to VCC, GND or VCC/2 (using two resistors ≤1M). Do not float this pin. GND (Pin 4): Ground Connection. CLK (Pin 5): Serial Clock Interface. Must be pulled high to VCC with external resistor. The pull-up current must be limited to 350µA. DATA (Pin 6): Open-Drain Connected Serial Data Interface. Must be pulled high to VCC with external resistor. The pull-up current must be limited to 350µA. OUT1 (Pin 7): Source Output of Switch 1. Maximum load of 300mA; controlled by 2nd LSB of command byte. VCC (Pin 8): Input Supply Voltage. Operating range from 2.7V to 5.5V. 4 LTC1710 W BLOCK DIAGRA POWER-ON RESET UNDERVOLTAGE LOCKOUT VCC 8 VCC 2V START AND STOP DETECTORS VCC ACK DATA 6 INPUT BUFFERS SHIFT REGISTER LOGIC 7 OUT1 A CLK 5 B OUTPUT LATCHES REGULATED CHARGE PUMPS THERMAL SHUTDOWN 1 SW0D COUNTER 2 OUT0 ADDRESS DECODER AD1 3 GND ADDRESS COMPARATOR 4 1710 BD WU W TI I G DIAGRA CLK tHD:STA tHIGH tSU:DAT tSU:STA tr tHD:DAT tf tLOW tSU:STO DATA START STOP 1710 TD U OPERATIO SMBus Operation SMBus is a serial bus interface that uses only two bus lines, DATA and CLK, to control low power peripheral devices in portable equipment. It consists of masters, also known as hosts, and slave devices. The master of the SMBus is always the one to initiate communications to the slave devices by varying the status of the DATA and CLK lines. The SMBus specification establishes a set of protocols that devices on the bus must follow for communications. The protocol that the LTC1710 uses is the Send Byte Protocol. In this protocol, the master first sends out a Start signal by switching the DATA line from high to low while CLK is high. (Because there may be more than one master on the same bus, an arbitration process takes place if two masters attempt to take control of the DATA line simultaneously; the first master that outputs a one while the other master is zero loses the arbitration and becomes a slave itself.) Upon detecting this Start signal, all slave devices on the bus wake up and prepare to shift in the next byte of data. 5 LTC1710 U OPERATIO The master then sends out the first byte. The first seven bits of this byte consist of the address of the device that the master wishes to communicate with. The last bit indicates whether the command will be a read (logic one) or write (logic zero). Because the LTC1710 is a slave device that can only be written to by a master, it will ignore the ensuing commands of the master if it wants to read from the LTC1710, even if the address sent by the master matches that of the LTC1710. After reception of the first byte, the slave device (LTC1710) with the matching address then acknowledges the master by pulling the DATA line low before the next rising clock edge. By now all other nonmatching slave devices will have gone back to their original standby states to wait for the next Start signal. Meanwhile, upon receiving the acknowledge from the matching slave, the master then sends out the command byte (see Table 1). executed on the Stop signal despite the fact that valid data were loaded into their output latches at different times. An example is shown in Figure 1. If somehow either the Start or the Stop signal is detected in the middle of a byte, the slave device (LTC1710) will regard this as an error and reject all previous data. Address The LTC1710 has an address of 10110XX; the five MSBs are hardwired, but the two LSBs are programmable by the user with the help of a three-state address pin. Refer to Table 2 for the pin configurations and their corresponding addresses. Table 2. Address Pin Truth Table AD1 GND VCC /2 VCC Table 1. Switch Control Table COMMAND Switch 0 Switch 1 XXXXXX00 SW0 Off SW1 Off XXXXXX01 SW0 On SW1 Off XXXXXX10 SW0 Off SW1 On XXXXXX11 SW0 On SW1 On After receiving the command byte, the slave device (LTC1710) needs to acknowledge the master again by pulling the DATA line low on the following clock cycle. The master then ends this Send Byte Protocol by sending the Stop signal, which is a transition from low to high on the DATA line while the CLK line is high. Valid data is shifted into the output latch on the last acknowledge signal; the output switch will not turn on, however, until the Stop signal is detected. This double buffering feature of the output latch allows the user to “daisy-chain” multiple SMBus devices such that their outputs are synchronously ADDRESS 1011000 1011001 1011010 To conserve standby current, it is preferable to tie the address pins to either VCC or GND. If three LTC1710s are needed, then the address pin can be tied to the third state of VCC /2 by using two equal value resistors (≤1M), see Figure 2. 5V 6 5 DATA CLK VCC SW0D 8 1 LTC1710 3 4 AD1 OUT0 GND OUT1 1M LOAD 1 2 7 LOAD 2 1M 1710 F02 Figure 2. The LTC1710 Programmed with Address 1011001 EXECUTION OF DATA STORED IN OUTPUT LATCH OF DEVICES WITH ADDR1, ADDR2 AND ADDR3 START ADDR1 A COMMAND A START ADDR2 A COMMAND A START ADDR3 A COMMAND A STOP 1710 F01 Figure 1. Daisy-Chain Example Example of Send Byte Protocol to Slave Address 1011000 Turning SW0 and SW1 On CLK START 1 0 1 1 0 0 0 (PROGRAMMABLE) 0 (WRITE) ACK 0 0 0 0 0 0 1 (SW1 ON) 1 (SW0 ON) ACK STOP DATA ADDRESS BYTE 6 COMMAND BYTE 1710 TA03 LTC1710 U OPERATIO Charge Pump To fully enhance the internal N-channel power switches, an internal charge pump is used to boost the gate drive to a maximum of 6V above VCC. The reason for the maximum charge pump output voltage limit is to protect the internal switches from excessive gate overdrive. A feedback network is used to limit the charge pump output once it is 6V above VCC. To prevent the power switches from turning on too fast, an internal current source is placed between the output of the charge pump and the gate of the power switch to control the ramp rate. Since the charge pumps are driving just the gates of the internal switches, only a small amount of current is required. Therefore, all the charge pump capacitors are integrated onboard. The drain of switch 1 is internally connected to VCC, however, the drain of switch 0 is user controlled through Pin 1. In other words, SMBus devices using different power supply voltages can be simultaneously switched by the same LTC1710. Power-On Reset and Undervoltage Lockout The LTC1710 starts up with both gate drives low. An internal power-on reset (POR) signal inhibits operation until about 300µs after VCC crosses the undervoltage lockout threshold (typically 2V). The circuit includes some hysteresis and delay to avoid nuisance resets. Once operation begins, VCC must drop below the threshold for at least 100µs to trigger another POR sequence. Input Threshold Anticipating the trend of lower and lower supply voltages, the SMBus is specified with a VIH of 1.4V and a VIL of 0.6V. While some SMBus parts may violate this stringent SMBus specification by specifying a higher VIH value for a corresponding higher input supply voltage, the LTC1710 meets and maintains the constant SMBus input threshold specification throughout the entire supply voltage range of 2.7V to 5.5V. Thermal Shutdown In the unlikely event that either power switch overheats, a thermal shutdown circuit, which is placed closely to the two switches, will activate and turn off the gate drives to both switches. The thermal shutdown circuit has a threshold of 120°C with a 15°C hysteresis. U TYPICAL APPLICATIONS The LTC1710, when used with the LT®1521-3.3, can switch a regulated 3.3V/300mA supply to a load (Figure 3). Also, with the help of the LT1304-5, the LTC1710 can be used to make a boost switching regulator with output disconnect and a low standby current of 22µA (Figure 5). 5V 5V 10µF 10µF 10µF 8 8 5 FROM SMBus 6 3 PROGRAMMABLE 3.3V VCC CLK OUT1 7 1µF LTC1710 DATA SW0D AD1 OUT0 GND 8 5 1 2 SWITCHED 3.3V VIN VOUT LT1521-3.3 SHDN SENSE 1 5 3.3V FROM SMBus 2 3 1.5µF 1710 F03 6 VCC 1 SW0D CLK OUT0 2 3.3V LOAD 7 5V LOAD LTC1710 DATA AD1 PROGRAMMABLE OUT1 GND 4 4 1710 F04 Figure 3. Low Dropout Regulator Switching a 3.3V/300mA Supply Figure 4. The LTC1710 Switching Two Different Voltage Loads 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 its circuits as described herein will not infringe on existing patent rights. 7 LTC1710 U TYPICAL APPLICATIONS 3.3V 8 5 FROM SMBus 10µF 1 VCC SW0D CLK 2 OUT0 LTC1710 6 DATA 3 AD1 + 7 OUT1 100µF 3 4 VIN SW GND PROGRAMMABLE 3.3V LOAD 1N5817 22µH* 499k 4 SENSE LT1304-5 1 604k LBI SHDN LBO GND 7 8 2 5V 200mA + 100k 2200µF LBO 5 *SUMIDA CD54-220 SHUTDOWN 1710 F05 Figure 5. Switching Regulator with Low-Battery Detect Using 22µA of Standby Current U PACKAGE DESCRIPTION Dimensions in inches (millimeters), unless otherwise noted. MS8 Package 8-Lead Plastic MSOP S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1660) (LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 0.118 ± 0.004* (3.00 ± 0.102) 8 7 6 8 5 0.118 ± 0.004** (3.00 ± 0.102) 0.192 ± 0.004 (4.88 ± 0.10) 1 2 3 5 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.034 ± 0.004 (0.86 ± 0.102) 0.010 – 0.020 × 45° (0.254 – 0.508) 0° – 6° TYP 0.021 ± 0.006 (0.53 ± 0.015) 6 4 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 7 SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) TYP 0.006 ± 0.004 (0.15 ± 0.102) * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 0.008 – 0.010 (0.203 – 0.254) 3 4 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 MSOP (MS8) 1197 2 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE SO8 0996 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1304 Micropower DC/DC Converter Low-Battery Detector Active in Shutdown LTC1470/LTC1471 Single and Dual PCMCIA Protected 3.3V/5V VCC Switches Current Limit LTC1473 Dual PowerPathTM Switch Matrix Current Limit with Timer LTC1623 SMBus Dual High Side Switch Controller Uses External Switches, Two Three-State Address Pins PowerPath is a trademark of Linear Technology Corporation. 8 Linear Technology Corporation 1710f LT/TP 0998 4K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com  LINEAR TECHNOLOGY CORPORATION 1998