TC654/TC655 Dual SMBus™ PWM Fan Speed Controllers With Fan Fault Detection Features: Description: • Temperature Proportional Fan Speed for Reduced Acoustic Noise and Longer Fan Life • FanSense™ Protects against Fan Failure and Eliminates the Need for 3-wire Fans • Overtemperature Detection (TC655) • Efficient PWM Fan Drive • Provides RPM Data • 2-Wire SMBus™-Compatible Interface • Supports Any Fan Voltage • Software Controlled Shutdown Mode for "Green" Systems • Supports Low-Cost NTC/PTC Thermistors • Space Saving 10-Pin MSOP Package • Temperature Range: -40°C to +85ºC The TC654 and TC655 are PWM mode fan speed controllers with FanSense technology for use with brushless DC fans. These devices implement temperature proportional fan speed control which lowers acoustic fan noise and increases fan life. The voltage at VIN (Pin 1) represents temperature and is typically provided by an external thermistor or voltage output temperature sensor. The PWM output (VOUT) is adjusted between 30% and 100%, based on the voltage at VIN. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need for an external thermistor. If VIN is not connected, the TC654/TC655 will start driving the fan at a default duty cycle of 39.33%. See Section 4.3 “Fan Start-up” for more details. Applications: • • • • • • • Personal Computers and Servers LCD Projectors Datacom and Telecom Equipment Fan Trays File Servers Workstations General Purpose Fan Speed Control Package Type 10-Pin MSOP VIN 1 10 VDD CF 2 9 VOUT 8 SENSE1 TC654 TC655 SCLK 3 SDA 4 7 SENSE2 GND 5 6 FAULT 2002-2014 Microchip Technology Inc. In normal fan operation, pulse trains are present at SENSE1 (Pin 8) and SENSE2 (Pin 7). The TC654/ TC655 use these pulses to calculate the fan revolutions per minute (RPM). The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC654/TC655 to assert a logic low alert signal (FAULT). The default threshold value is 500 RPM. Also, if this condition occurs, F1F (bit 0<0>) or F2F (bit 1<0>) in the Status Register will also be set to a ‘1’. An over-temperature condition is indicated when the voltage at VIN exceeds 2.6V (typical). The TC654/ TC655 devices indicate this by setting OTF(bit 5<X>) in the Status Register to a '1'. The TC655 device also pulls the FAULT line low during an over-temperature condition. The TC654/TC655 devices are available in a 10-Pin MSOP package and consume 150 µA during operation. The devices can also enter a low-power Shutdown mode (5 µA, typ.) by setting the appropriate bit in the Configuration Register. The operating temperature range for these devices is -40°C to +85ºC. DS20001734C-page 1 TC654/TC655 Functional Block Diagram TC654/TC655 – VIN – VOTF + Note OTF VDD + + Control Logic VOUT Start-up Timer FAULT – CF VMIN Clock Generator Missing Pulse Detect SCLK SDA SENSE1 – Serial Port Interface 100 mV (typ.) GND 50 k 50 k SENSE2 – 100 mV (typ.) Note: OTF condition applies for the TC655 device only. DS20001734C-page 2 2002-2014 Microchip Technology Inc. TC654/TC655 1.0 ELECTRICAL CHARACTERISTICS PIN FUNCTION TABLE Name Function Absolute Maximum Ratings * VIN Analog Input VDD...................................................................................6.5V CF Analog Output Input Voltages ...................................... -0.3V to (VDD + 0.3V) SCLK Serial Clock Input Output Voltages .................................... -0.3V to (VDD + 0.3V) SDA Serial Data In/Out (Open Drain) Storage temperature .....................................-65°C to +150°C GND Ground Ambient temp. with power applied ................-40°C to +125°C FAULT Digital (Open Drain) Output Maximum Junction Temperature, TJ ............................. 150°C SENSE2 Analog Input ESD protection on all pins 4 kV *Notice: Stresses above those listed under “Maximum ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. SENSE1 Analog Input VOUT Digital Output VDD Power Supply Input ELECTRICAL SPECIFICATIONS Electrical Characteristics: Unless otherwise noted, all limits are specified for VDD = 3.0V to 5.5V, -40°C <TA < +85°C. Sym. Min. Typ. Max. Units Supply Voltage Parameters VDD 3.0 — 5.5 V Operating Supply Current IDD — 150 300 µA Pins 7, 8, 9 Open IDDSHDN — 5 10 µA Pins 7, 8, 9 Open VOUT Rise Time tR — — 50 µsec IOH = 5 mA, Note 1 VOUT Fall Time tF — — 50 Sink Current at VOUT Output IOL 1.0 — — µsec IOL = 1 mA, Note 1 mA VOL = 10% of VDD Source Current at VOUT Output IOH 5.0 — — mA VOH = 80% of VDD F 26 30 34 Hz CF = 1 µF VIN Input Voltage for 100% PWM duty-cycle VC(MAX) 2.45 2.6 2.75 V VC(MAX) - VC(MIN) VCRANGE 1.25 1.4 1.55 V — 10M — IIN -1.0 — +1.0 µA VTHSENSE 80 100 120 mV VOL — — 0.3 V tFAULT — 2.4 — sec -15 — +15 % Shutdown Mode Supply Current Conditions VOUT PWM Output PWM Frequency VIN Input VIN Input Resistance VIN Input Leakage Current VDD = 5.0V SENSE Input SENSE Input Threshold Voltage with Respect to GND FAULT Output FAULT Output LOW Voltage FAULT Output Response Time IOL = 2.5 mA Fan RPM-to-Digital Output Fan RPM ERROR RPM > 1600 Note 1: Not production tested, ensured by design, tested during characterization. 2: For 5.0V > VDD 5.5V, the limit for VIH = 2.2V. 2002-2014 Microchip Technology Inc. DS20001734C-page 3 TC654/TC655 ELECTRICAL SPECIFICATIONS (CONTINUED) Electrical Characteristics: Unless otherwise noted, all limits are specified for VDD = 3.0V to 5.5V, -40°C <TA < +85°C. Parameters Sym. Min. Typ. Max. Units Conditions VIH 2.1 — — V Logic Input Low VIL — — 0.8 V Logic Output Low VOL — — 0.4 V IOL = 3 mA Note 1 2-Wire Serial Bus Interface Logic Input High Input Capacitance SDA, SCLK CIN — 10 15 pF ILEAK -1.0 — +1.0 µA IOLSDA 6 — — mA I/O Leakage Current SDA Output Low Current Note 2 VOL = 0.6V Note 1: Not production tested, ensured by design, tested during characterization. 2: For 5.0V > VDD 5.5V, the limit for VIH = 2.2V. TEMPERATURE SPECIFICATIONS Electrical Characteristics: Unless otherwise noted, all parameters apply at VDD = 3.0 V to 5.5 V Parameters Symbol Min Typ Max Units Specified Temperature Range TA -40 — +85 °C Operating Temperature Range TA -40 — +125 °C Storage Temperature Range TA -65 — +150 °C JA — 113 — °C/W Conditions Temperature Ranges Thermal Package Resistances Thermal Resistance, 10 Pin MSOP TIMING SPECIFICATIONS Electrical Characteristics: Unless otherwise noted, all limits are specified for VDD = 3.0V to 5.5V, -40°C <TA < +85°C Parameters Sym Min Typ Max Units Conditions fSC 0 — 100 kHz Low Clock Period tLOW 4.7 — — µsec Note 1 High Clock Period tHIGH 4.7 — — µsec Note 1 SCLK and SDA Rise Time tR — — 1000 nsec Note 1 SCLK and SDA Fall Time tF — — 300 nsec Note 1 SMBus Interface (See Figure 1-1) Serial Port Frequency Note 1 tSU(START) 4.7 — — µsec Note 1 SCLK Clock Period Time tSC 10 — — µsec Note 1 Start Condition Hold Time tH(START) 4.0 — — µsec Note 1 Data in SetupTime to SCLK High tSU-DATA 250 — — nsec Note 1 Data in Hold Time after SCLK Low tH-DATA 300 — — nsec Note 1 Stop Condition Setup Time tSU(STOP) 4.0 — — µsec Note 1 Bus Free Time Prior to New Transition tIDLE 4.7 — Start Condition Setup Time µsec Note 1 and Note 2 Note 1: Not production tested, ensured by design, tested during characterization. 2: Time the bus must be free before a new transmission can start. DS20001734C-page 4 2002-2014 Microchip Technology Inc. TC654/TC655 SMBus Write Timing Diagram A B tLOW tHIGH C D E F G H I J K M L SCLK SDA tSU(START) tH(START) tSU-DATA tH-DATA tSU(STOP)tIDLE F = Acknowledge Bit Clocked into Master G = MSB of Data Clocked into Slave H = LSB of Data Clocked into Slave I = Slave Pulls SDA Line Low A = Start Condition B = MSB of Address Clocked into Slave C = LSB of Address Clocked into Slave D = R/W Bit Clocked into Slave E = Slave Pulls SDA Line Low J = Acknowledge Clocked into Master K = Acknowledge Clock Pulse L = Stop Condition, Data Executed by Slave M = New Start Condition SMBus Read Timing Diagram A B tLOW tHIGH C D E F G H I J K SCLK SDA tSU(START) tH(START) tSU-DATA tSU(STOP) A = Start Condition E = Slave Pulls SDA Line Low I = Acknowledge Clock Pulse B = MSB of Address Clocked into Slave F = Acknowledge Bit Clocked into Master J = Stop Condition C = LSB of Address Clocked into Slave G = MSB of Data Clocked into Master K = New Start Condition D = R/W Bit Clocked into Slave H = LSB of Data Clocked into Master FIGURE 1-1: tIDLE Bus Timing Data. 2002-2014 Microchip Technology Inc. DS20001734C-page 5 TC654/TC655 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. 180 14 Pins 7,8, and 9 Open 175 VOL = 0.1 VDD VDD = 5.5 V 170 IDD (µA) 165 VDD = 3.0 V 160 155 150 145 140 Sink Current (mA) 2.0 12 VDD = 5.5 V 10 8 VDD = 5.0 V 6 VDD = 4.0 V 4 135 VDD = 3.0 V 130 2 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 Temperature (°C) IDD vs. Temperature. FIGURE 2-4: Temperature. 9.000 50 8.000 45 35 50 65 80 95 110 125 PWM, Sink Current vs. IOL = 2.5 mA VDD = 3.0 V 7.000 Fault V OL (mV) Shutdown I DD (µA) FIGURE 2-1: 20 Temperature (°C) VDD = 5.5 V 6.000 5.000 4.000 VDD = 3.0 V 3.000 40 35 30 VDD = 5.0 V 25 VDD = 5.5 V VDD = 4.0 V 20 2.000 1.000 15 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 Temperature (ºC) IDD Shutdown vs. FIGURE 2-2: Temperature. 20 35 50 65 80 95 110 125 Temperature (ºC) FIGURE 2-5: Fault VOL vs. Temperature. 32 Source Current (mA) VOH = 0.8VDD 30 VDD = 5.5 V 25 20 VDD = 5.0 V VDD = 4.0 V 15 PWM Frequency (Hz) CF = 1.0 µF 35 31 VDD = 5.5 V 30 VDD = 3.0 V 29 28 VDD = 3.0 V 10 27 5 -40 -40 -25 -10 5 20 35 50 65 80 95 Temperature (°C) FIGURE 2-3: Temperature. DS20001734C-page 6 -25 110 125 PWM, Source Current vs. -10 5 20 35 50 65 80 95 110 125 Temperature (ºC) FIGURE 2-6: Temperature. PWM Frequency vs. 2002-2014 Microchip Technology Inc. TC654/TC655 10 50 VOL = 0.4 V 8 40 VDD = 5.5 V VDD = 5.0 V 35 30 RPM Error (%) SDA IOL (mA) CF = 1.0 µF 9 45 6 5 VDD = 3.0 V 4 3 2 VDD = 4.0 V 25 7 VDD = 5.0 V 1 VDD = 3.0 V 20 VDD = 5.5 V 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 Temperature (ºC) FIGURE 2-7: SDA IOL vs. Temperature. FIGURE 2-10: Temperature. 2.620 2.605 2.600 VDD = 5.0 V 2.595 2.590 VDD = 4.0 V 2.585 2.580 VDD = 3.0 V VTHSENSE Hysteresis (mV) 2.610 VCMax (V) 50 65 80 95 110 125 95 110 125 RPM %error vs. 45 VDD = 5.5 V 2.615 2.575 40 35 VDD = 3.0V 30 VDD = 5.5V 25 20 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 Temperature (ºC) VDD = 3.0 V 1.195 VDD = 5.5 V VDD = 5.0 V 1.190 VDD = 4.0 V 1.185 1.180 -40 -25 -10 5 20 35 50 65 80 95 110 125 VCMIN vs. Temperature. 2002-2014 Microchip Technology Inc. 50 65 80 150 140 130 VDD = 3.0 V 120 VDD = 5.0 V 110 100 90 80 -40 -25 -10 Temperature (ºC) FIGURE 2-9: 35 FIGURE 2-11: Sense Threshold (VTHSENSE) Hysteresis vs. Temperature. SDA & SCLK Hysteresis (mV) 1.205 1.200 20 Temperature (ºC) VCMAX vs. Temperature. FIGURE 2-8: VCMIN (V) 35 Temperature (ºC) 5 20 35 50 65 80 95 110 125 Temperature (ºC) FIGURE 2-12: Temperature. SDA, SCLK Hysteresis vs. DS20001734C-page 7 TC654/TC655 3.0 PIN FUNCTIONS The descriptions of the pins are listed in Table 3-1. TABLE 3-1: PIN FUNCTION TABLE Name Function VIN Analog Input CF Analog Output SCLK Serial Clock Input SDA Serial Data In/Out (Open Drain) GND Ground FAULT Digital (Open Drain) Output SENSE2 Analog Input SENSE1 Analog Input VOUT Digital Output VDD Power Supply Input 3.1 Analog Input (VIN) 3.6 Analog Input (SENSE2) A voltage range of 1.62V to 2.6V (typical) on this pin drives an active duty-cycle of 30% to 100% on the VOUT pin. Fan current pulses are detected at this pin. These pulses are counted and used in the calculation of the Fan 2 RPM. 3.2 3.7 Analog Output (CF) Analog Input (SENSE1) Positive terminal for the PWM ramp generator timing capacitor. The recommended CF is 1 µF for 30 Hz PWM operation. Fan current pulses are detected at this pin. These pulses are counted and used in the calculation of the Fan 1 RPM. 3.3 3.8 SMBus Serial Clock Input (SCLK) Clocks data into and out of the TC654/TC655. See Section 5.0 “Serial Communication” for more information on the serial interface. This active high complimentary output drives the base of an external transistor or the gate of a MOSFET. 3.9 3.4 Serial Data (Bi-directional) (SDA) Serial data is transferred on the SMBus in both directions using this pin. See Section 5.0 “Serial Communication” for more information on the serial interface. 3.5 Digital Output (VOUT) Power Supply Input (VDD) The VDD pin with respect to GND provides power to the device. This bias supply voltage may be independent of the fan power supply. Digital (Open Drain) Output (FAULT) When the fan’s RPM falls below the user-set RPM threshold (or OTF occurs with TC655), a logic low signal is asserted. DS20001734C-page 8 2002-2014 Microchip Technology Inc. TC654/TC655 4.0 DEVICE OPERATION can be set to provide a predictive fan failure feature. This feature can be used to give a system warning and, in many cases, help to avoid a system thermal shutdown condition. The fan RPM data and threshold registers are available over the SMBus interface which allows for complete system control. The TC654 and TC655 devices allow you to control, monitor and communicate (via SMBus) fan speed for 2wire and 3-wire DC brushless fans. By pulse-width modulating (PWM) the voltage across the fan, the TC654/TC655 controls fan speed according to the system temperature.The goal of temperature proportional fan speed control is to reduce fan power consumption, increase fan life and reduce system acoustic noise. With the TC654 and TC655 devices, fan speed can be controlled by the analog input VIN or the SMBus interface, allowing for high system flexibility. The TC654/TC655 devices are identical in every aspect except for how they indicate an over-temperature condition. When VIN voltage exceeds 2.6V (typical), both devices will set OTF (bit 5<X>) in the Status Register to a '1'. The TC655 will additionally pull the FAULT output low during an over-temperature condition. The TC654 and TC655 also measure and monitor fan revolutions per minute (RPM). A fan’s speed (RPM) is a measure of its health. As a fan’s bearings wear out, the fan slows down and eventually stops (locked rotor). By monitoring the fan’s RPM level, the TC654/TC655 devices can detect open, shorted, unconnected and locked rotor fan conditions. The fan speed threshold +5V +12V +5V FAN 1 C2 1 µF R1 RISO1 NTC Thermistor 100 k @ 25°C 34.8 k 715 10 1 C1 0.01 µF R2 VIN CF VOUT VDD RISO2 9 715 14.7 k 2 SENSE1 8 CSENSE1 CF 0.1 µF 1.0 µF TC654/TC655 RSCLK +5V 20 k SENSE2 7 3 FAN 2 CSENSE2 0.1 µF SCLK RSENSE1 RSENSE2 +5V +5V PIC® Microcontroller RFAULT 4 RSDA FAULT SDA 6 20 k GND 5 20 k Note: Refer to Table 7-1 for RSENSE1 and RSENSE2 values. FIGURE 4-1: Typical Application Circuit. 2002-2014 Microchip Technology Inc. DS20001734C-page 9 TC654/TC655 4.1 Fan Speed Control Methods T The speed of a DC brushless fan is proportional to the voltage across it. For example, if a fan’s rating is 5000 RPM at 12V, it’s speed would be 2500 RPM at 6V. This, of course, will not be exact, but should be close. There are two main methods for fan speed control. The first is pulse width modulation (PWM) and the second is linear. Using either method the total system power requirement to run the fan is equal. The difference between the two methods is where the power is consumed. The following example compares the two methods for a 12V, 120 mA fan running at 50% speed. With 6V applied across the fan, the fan draws an average current of 68 mA. Using a linear control method, there are 6V across the fan and 6V across the drive element. With 6V and 68 mA, the drive element is dissipating 410 mW of power. Using the PWM approach, the fan is modulated at a 50% duty cycle, with most of the 12V being dropped across the fan. With 50% duty cycle, the fan draws an RMS current of 110 mA and an average current of 72 mA. Using a MOSFET with a 1 RDS(on) (a fairly typical value for this low current) the power dissipation in the drive element would be: 12 mW (Irms2 * RDS(on)). Using a standard 2N2222A NPN transistor (assuming a Vce-sat of 0.8V), the power dissipation would be 58 mW (Iavg* Vce-sat). The PWM approach to fan speed control causes much less power dissipation in the drive element. This allows smaller devices to be used and will not require any special heatsinking to get rid of the power being dissipated in the package. The other advantage to the PWM approach is that the voltage being applied to the fan is always near 12V. This eliminates any concern about not supplying a high enough voltage to run the internal fan components, which is very relevant in linear fan speed control. 4.2 PWM Fan Speed Control The TC654 and TC655 devices implement PWM fan speed control by varying the duty cycle of a fixed frequency pulse train. The duty cycle of a waveform is the on time divided by the total period of the pulse. For example, given a 100 Hz waveform (10 msec.) with an on time of 5.0 msec, the duty cycle of this waveform is 50% (5.0 msec/10.0 msec). An example of this is illustrated in Figure 4-2. DS20001734C-page 10 Ton Toff D = Duty Cycle D = Ton / T FIGURE 4-2: Waveform. T = Period T = 1/F F = Frequency Duty Cycle Of A PWM The TC654 and TC655 generate a pulse train with a typical frequency of 30 Hz (CF = 1 µF). The duty cycle can be varied from 30% to 100%. The pulse train generated by the TC654/TC655 devices drives the gate of an external N-channel MOSFET or the base of an NPN transistor (Figure 4-3). See Section 7.5 “Output Drive Device Selection” for more information on output drive device selection. 12V FAN VDD D TC654/ VOUT TC655 G Qdrive S GND FIGURE 4-3: PWM Fan Drive. By modulating the voltage applied to the gate of the MOSFET Qdrive, the voltage applied to the fan is also modulated. When the VOUT pulse is high, the gate of the MOSFET is turned on, pulling the voltage at the drain of Qdrive to 0V. This places the full 12V across the fan for the Ton period of the pulse. When the duty cycle of the drive pulse is 100% (full on, Ton = T), the fan will run at full speed. As the duty cycle is decreased (pulse on time “Ton” is lowered), the fan will slow down proportionally. With the TC654 and TC655 devices, the duty cycle can be controlled through the analog input pin (VIN) or through the SMBus interface by using the Duty-Cycle Register. See Section 4.5 “Duty Cycle Control (VIN and Duty-Cycle Register)” for more details on duty cycle control. 2002-2014 Microchip Technology Inc. TC654/TC655 4.3 Fan Start-up Often overlooked in fan speed control is the actual start-up control period. When starting a fan from a nonoperating condition (fan speed is zero RPM), the desired PWM duty cycle or average fan voltage can not be applied immediately. Since the fan is at a rest position, the fan’s inertia must be overcome to get it started. The best way to accomplish this is to apply the full rated voltage to the fan for one second. This will ensure that in all operating environments, the fan will start and operate properly. The TC654 and TC655 devices implement this fan control feature without any user programming. During a power-up or release from shutdown condition, the TC654 and TC655 devices force the VOUT output to a 100% duty cycle, turning the fan full on for one second (CF = 1 µF). Once the one second period is over, the TC654/TC655 devices will look to see if SMBus or VIN control has been selected in the Configuration Register (DUTYC bit 5<0>). Based on this register, the device will choose which input will control the VOUT duty cycle. Duty cycle control based on VIN is the default state. If VIN control is selected and the VIN pin is open (nothing is connected to the VIN pin), then the TC654/TC655 will default to a duty cycle of 39.33%. This sequence is shown in Figure 4-4. This integrated one second startup feature will ensure the fan starts-up every time. quency is linear. If a frequency of 15 Hz is desired, a capacitor value of 2.0 µF should be used. The frequency should be kept in the range of 15 Hz to 35 Hz. See Section 7.2 “Setting the PWM Frequency” for more details. 4.5 Duty Cycle Control (VIN and DutyCycle Register) The duty cycle of the VOUT PWM drive signal can be controlled by either the VIN analog input pin or by the Duty-Cycle Register, which is accessible via the SMBus interface. The control method is selectable via DUTYC (bit 5<0>) of the Configuration Register. The default state is for VIN control. If VIN control is selected and the VIN pin is open, the PWM duty cycle will default to 39.33%. The duty cycle control method can be changed at any time via the SMBus interface. VIN is an analog input pin. A voltage in the range of 1.62V to 2.6V (typical) at this pin commands a 30% to 100% duty cycle on the VOUT output, respectively. If the voltage at VIN falls below the 1.62V level, the duty cycle will not go below 30%. The relationship between the voltage at VIN and the PWM duty cycle is shown in Figure 4-5. 100 90 Duty Cycle (%) 80 Power-Up or Release from SHDN One Second Pulse 70 60 50 40 30 20 10 Select SMBus YES 0 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 Input Voltage (VIN) NO Default PWM: 39.33% YES SMBus PWM Duty Cycle Control VIN Open? NO VIN PWM Duty Cycle Control FIGURE 4-4: 4.4 Power-Up Flow Chart. PWM Drive Frequency (CF) As previously discussed, the TC654 and TC655 devices operate with a fixed PWM frequency. The frequency of the PWM drive output (VOUT) is set by a capacitor at the CF pin. With a 1 µF capacitor at the CF pin, the typical drive frequency is 30 Hz. This frequency can be raised, by decreasing the capacitor value, or lowered, by increasing the capacitor value. The relationship between the capacitor value and the PWM fre- 2002-2014 Microchip Technology Inc. FIGURE 4-5: Voltage (Typical). PWM Duty Cycle vs. VIN For the TC655 device, if the voltage at VIN exceeds the 2.6V (typical) level, an over-temperature fault indication will be given by asserting a low at the FAULT output and setting OTF (bit 5<X>) in the Status Register to a ‘1’. A thermistor network or any other voltage output thermal sensor can be used to provide the voltage to the VIN input. The voltage supplied to the VIN pin can actually be thought of as a temperature. For example, the circuit shown in Figure 4-6 represents a typical solution for a thermistor based temperature sensing network. See Section 7.3 “Temperature Sensor Design” for more details. DS20001734C-page 11 TC654/TC655 This method of control allows for more sophisticated algorithms to be implemented by utilizing microcontrollers or microprocessors in the system. In this way, multiple system temperatures can be taken into account for determining the necessary fan speed. +5V NTC Thermistor 100 k @ 25°C R1 34.8 k VIN C1 0.01 µF R2 14.7 k GND FIGURE 4-6: Network. TC654/ TC655 NTC Thermistor Sensor The second method for controlling the duty cycle of the PWM output (VOUT) is via the SMBus interface. In order to control the PWM duty cycle via the SMBus, DUTYC (bit 5<0>) of the Configuration Register (Register 6.3) must be set to a ‘1’. This tells the TC654/TC655 device that the duty cycle should be controlled by the Duty Cycle Register. Next, the Duty Cycle Register must be programmed to the desired value. The Duty Cycle Register is a 4 Bit read/write register that allows duty cycles from 30% to 100% to be programmed. Table 4-1 shows the binary codes for each possible duty cycle. TABLE 4-1: DUTY-CYCLE REGISTER (DUTY-CYCLE) 4-BITS, READ/WRITE Duty-Cycle Register (Duty Cycle) D(3) D(2) D(1) D(0) 0 0 0 0 30% 0 0 0 1 34.67% 0 0 1 0 39.33% (default for VIN open and when SMBus is not selected) 0 0 1 1 44% 0 1 0 0 48.67% 0 1 0 1 53.33% 0 1 1 0 58% 0 1 1 1 62.67% 1 0 0 0 67.33% 1 0 0 1 72% 1 0 1 0 76.67% 1 0 1 1 81.33% 1 1 0 0 86% 1 1 0 1 90.67% 1 1 1 0 95.33% 1 1 1 1 100% DS20001734C-page 12 Duty-Cycle As shown in Table 4-1, the duty cycle has more of a step function look than did the VIN control approach. Because the step changes in duty cycle are small, they are rarely audibly noticeable, especially when the fans are integrated into the system. 4.6 PWM Output (VOUT) The VOUT pin is designed to drive two low-cost NPN transistors or N-channel MOSFETs as the low side power switching elements in the system as is shown in Figure 4-7. These switching elements are used to turn the fans on and off at the PWM duty cycle commanded by the VOUT output. This output has complementary drive (pull up and pull down) and is optimized for driving NPN transistors or N-channel MOSFETs (see Section 2.0 “Typical Performance CURVES” for sink and source current capability of the VOUT drive stage). The external device needs to be chosen to fit the voltage and current rating of the fan in a particular application (Refer to Section 7.5 “Output Drive Device Selection” Output Drive Device Selection). NPN transistors are often a good choice for low-current fans. If a NPN transistor is chosen, a base current-limiting resistor should be used. When using a MOSFET as the switching element, it is sometimes a good idea to have a gate resistor to help slow down the turn on and turn off of the MOSFET. As with any switching waveform, fast rising and falling edges can sometimes lead to noise problems. As previously stated, the VOUT output will go to 100% duty cycle during power-up and release from shutdown conditions. The VOUT output only shuts down when commanded to do so via the Configuration Register (SDM (bit 0<0>)). Even when a locked rotor condition is detected, the VOUT output will continue to pulse at the programmed duty cycle. 4.7 Sensing Fan Operation (SENSE1 & SENSE2) The TC654 and TC655 also feature Microchip's proprietary FanSense technology. During normal fan operation, commutation occurs as each pole of the fan is energized. The fan current pulses created by the fan commutation are sensed using low value current sense resistors in the ground return leg of the fan circuit. The voltage pulses across the sense resistor are then AC coupled through capacitors to the SENSE pins of the TC654/TC655 device. These pulses are utilized for calculating the RPM of the individual fans. The threshold voltage for the SENSE pins is 100 mV (typical). The 2002-2014 Microchip Technology Inc. TC654/TC655 peak of the voltage pulse at the SENSE pins must exceed the 100 mV (typical) threshold in order for the pulse to be counted in the fan RPM measurement. See Section 7.4 “FanSense Network (RSENSE & CSENSE)” for more details on selecting the appropriate current sense resistor and coupling capacitor values. FAN 1 FAN 2 RISO1 RISO2 VOUT SENSE1 TC654/ TC655 CSENSE1 RSENSE1 SENSE2 CSENSE2 GND FIGURE 4-7: RSENSE2 Fan Current Sensing. By selecting F1PPR (bits 2-1<01>) and F2PPR (bits 43<01>) in the Configuration Register, the TC654 and TC655 can be programmed to calculate RPM data for fans with 1, 2, 4 or 8 current pulses per rotation. The default state assumes a fan with 2 pulses per rotation. The measured RPM data is then stored in the RPMOUTPUT1 (RPM1, for SENSE1 input) and RPM-OUTPUT2 (RPM2, for SENSE2 input) Registers. These registers are 9-Bit Read-Only registers which store RPM data with 25 RPM resolution. By setting RES (bit 6<0>) of the Configuration Register to a ‘1’, the RPM data can be read with 25 RPM resolution. If this Bit is left in the default state of '0', the RPM data will only be readable with resolution of 50 RPMs, which represents 8-Bit data. The maximum fan RPM reading is 12775 RPM. If this value is exceeded, counter overflow bits in the Status Register are set. R1CO (bit 3<0>) and R2CO (bit 4<0>) in the Status Register represent the RPM1 and RPM2 counter overflow bits for the RPM1 and RPM2 registers, respectively. These bits will automatically be reset to zero if the fan RPM reading has been below the maximum value of 12775 RPM for 2.4 seconds. 4.8 Fan Fault Threshold and Indication (FAULT) For the TC654 and TC655 devices, a fault condition exists whenever a fan’s sensed RPM level falls below the user programmable threshold. The RPM threshold values for fan fault detection are set in the FAN_FAULT1 and FAN_FAULT2 Registers (8-bit, read/ write). The RPM threshold represents the fan speed at which the TC654/TC655 devices will indicate a fan fault. This threshold can be set at lower levels to indicate fan locked rotor conditions or set to higher levels to give indications for predictive fan failure. It is recommended that the RPM threshold be at least 10% lower than the minimum fan speed which occurs at the lowest duty cycle set point. The default value for the fan RPM thresholds is 500 RPM. If the fan's sensed RPM is less than the fan fault threshold for 2.4 seconds (typical), a fan fault condition is indicated. When a fault condition due to low fan RPM occurs, a logic low is asserted at the FAULT output. F1F (bit 0<0>) and F2F (bit 1<0>) in the Status Register are set to ‘1’ for respective low RPM levels on the SENSE1 and SENSE2 inputs. The FAULT output and the fault bits in the Status Register can be reset by setting FFCLR (bit 7<0>) in the Configuration Register to a ‘1’. For the TC655 device, a fault condition is also indicated when an Over-Temperature Fault condition occurs. This condition occurs when the VOUT duty cycle exceeds the 100% value indicating that no additional cooling capability is available. For this condition, a logic low is asserted at the FAULT output and OTF (bit 5<X>) of the Status Register, the over-temperature fault indicator, is set to a ‘1’ (The TC654 also indicates an overtemperature condition via the OTF bit in the status register). If the duty cycle then decreases below 100%, the FAULT output will be released and OTF (bit 5<X>) of the Status Register will be reset to ‘0’. 4.9 Low-Power Shutdown Mode Some applications may have operating conditions where fan cooling is not required as a result of low ambient temperature or light system load. During these times it may be desirable to shut the fans down to save power and reduce system noise. The TC654/TC655 devices can be put into a low-power Shutdown mode by setting SDM (bit 0<0>) in the Configuration register to a ‘1’ (this bit is the shutdown bit). When the TC654/TC655 devices are in Shutdown mode, all functions except for the SMBus interface are suspended. During this mode of operation, the TC654 and TC655 devices will draw a typical supply current of only 5 µA. Normal operation will resume as soon as Bit 0 in the Configuration Register is reset to ‘0’. See Table 6-1 for RPM1, RPM2 and Status Register command byte assignments. 2002-2014 Microchip Technology Inc. DS20001734C-page 13 TC654/TC655 When the TC654/TC655 devices are brought out of a Shutdown mode by resetting SDM (bit 0<0>) in the Configuration Register, all of the registers (except for the Configuration and FAN_FAULT1 and 2 registers) assume their default power-up states. The Configuration Register and the FAN_FAULT1 and 2 Registers maintain the states they were in prior to the device being put into the Shutdown mode. Since these are the registers which control the parts operation, the part does not have to be reprogrammed for operation when it comes out of Shutdown mode. 4.10 SMBus Interface (SCLK & SDA) The TC654/TC655 feature an industry-standard, 2-wire serial interface with factory-set addresses. By communicating with the TC654/TC655 device registers, functions like PWM duty cycle, low-power Shutdown mode and fan RPM threshold can be controlled. Critical information, such as fan fault, over-temperature and fan RPM, can also be obtained via the device data registers. The available data and control registers make the TC654/TC655 devices very flexible and easy to use. All of the available registers are detailed in Section 6.0 “Register Set”. 4.11 SMBus Slave Address The slave address of the TC654/TC655 is 0011 011 and is fixed. This address is different from industrystandard digital temperature sensors (like TCN75) and, therefore, allows the TC654/TC655 to be utilized in systems in conjunction with these components. Please contact Microchip Technology Inc. if alternate addresses are required. DS20001734C-page 14 2002-2014 Microchip Technology Inc. TC654/TC655 5.0 SERIAL COMMUNICATION 5.1 SMBus 2-Wire Interface The Serial Clock Input (SCLK) and the bi-directional data port (SDA) form a 2-wire bi-directional serial port for communicating with the TC654/TC655. The following bus protocols have been defined: • Data transfer may be initiated only when the bus is not busy. • During data transfer, the data line must remain stable whenever the clock line is high. Changes in the data line while the clock line is high will be interpreted as a Start or Stop condition. Accordingly, the following Serial Bus conventions have been defined. TABLE 5-1: TC654/TC655 SERIAL BUS CONVENTIONS Term Description Transmitter The device sending data to the bus. Receiver The device receiving data from the bus. Master The device which controls the bus: initiating transfers (Start), generating the clock and terminating transfers (Stop). Slave The device addressed by the master. Start A unique condition signaling the beginning of a transfer indicated by SDA falling (High to Low) while SCLK is high. Stop A unique condition signaling the end of a transfer indicated by SDA rising (Low to High) while SCLK is high. ACK A Receiver acknowledges the receipt of each byte with this unique condition. The Receiver pulls SDA low during SCLK high of the ACK clockpulse. The Master provides the clock pulse for the ACK cycle. are initiated by a Start condition (Start), followed by a device address byte and one or more data bytes. The device address byte includes a Read/Write selection bit. Each access must be terminated by a Stop Condition (Stop). A convention call Acknowledge (ACK) confirms the receipt of each byte. Note that SDA can only change during periods when SCLK is low (SDA changes while SCLK is high are reserved for Start and Stop conditions). All bytes are transferred MSB (most significant bit) first. 5.1.2 MASTER/SLAVE The device that sends data onto the bus is the transmitter and the device receiving data is the receiver. The bus is controlled by a master device which generates the serial clock (SCLK), controls the bus access and generates the Start and Stop conditions. The TC654/ TC655 always work as a slave device. Both master and slave devices can operate as either transmitter or receiver, but the master device determines which mode is activated. 5.1.3 START CONDITION (START) A high-to-low transition of the SDA line while the clock (SCLK) is high determines a Start condition. All commands must be preceded by a Start condition. 5.1.4 ADDRESS BYTE Immediately following the Start Condition, the host must transmit the address byte to the TC654/TC655. The 7-bit SMBus address for the TC654/TC655 is 0011 011. The 7-bit address transmitted in the serial bit stream must match for the TC654/TC655 to respond with an Acknowledge (indicating the TC654/TC655 is on the bus and ready to accept data). The eighth bit in the Address Byte is a Read-Write Bit. This bit is a ‘1’ for a read operation or ‘0’ for a write operation. During the first phase of any transfer, this bit will be set = 0 to indicate that the command byte is being written. 5.1.5 STOP CONDITION (STOP) Busy Communication is not possible because the bus is in use. A low-to-high transition of the SDA line while the clock (SCLK) is high determines a Stop condition. All operations must be ended with a Stop condition. NOT Busy When the bus is idle, both SDA and SCLK will remain high. 5.1.6 Data Valid The state of SDA must remain stable during the high period of SCLK in order for a data bit to be considered valid. SDA only changes state while SCLK is low during normal data transfers. (See Start and Stop conditions) 5.1.1 DATA TRANSFER The TC654/TC655 support a bi-directional 2-Wire bus and data transmission protocol. The serial protocol sequencing is illustrated in Figure 1-1. Data transfers 2002-2014 Microchip Technology Inc. DATA VALID The state of the data line represents valid data when, after a Start condition, the data line is stable for the duration of the high period of the clock signal. The data on the line must be changed during the low period of the clock signal. There is one clock pulse per bit of data. Each data transfer is initiated with a Start condition and terminated with a Stop condition. The number of the data bytes transferred between the Start and Stop conditions is determined by the master device and is unlimited. DS20001734C-page 15 TC654/TC655 5.1.7 ACKNOWLEDGE (ACK) last byte that has been clocked out of the slave. In this case, the slave (TC654/TC655) will leave the data line high to enable the master device to generate the Stop condition. Each receiving device, when addressed, is obliged to generate an acknowledge bit after the reception of each byte. The master device must generate an extra clock pulse, which is associated with this acknowledge bit. 5.2 The TC654/TC655 devices communicate with three standard SMBus protocols. These are the write byte, read byte and receive byte. The receive byte is a shortened method for reading from, or writing to, a register which had been selected by the previous read or write command. These transmission protocols are shown in Figures 5-1, 5-2 and 5-3. The device that acknowledges has to pull down the SDA line during the acknowledge clock pulse in such a way that the SDA line is stable low during the high period of the acknowledge related clock pulse. Setup and hold times must be taken into account. During reads, a master device must signal an end of data to the slave by not generating an acknowledge bit on the S ADDRESS WR ACK 7 Bits S DATA ACK P 8 Bits Data Byte: data goes into the register set by the command byte. SMBus Protocol: Write Byte Format. ADDRESS WR ACK 7 Bits ACK 8 Bits ADDRESS RD ACK 7 Bits FIGURE 5-2: COMMAND Command Byte: selects which register you are writing to. DATA NACK P 8 Bits Slave Address: repeated due to change in data flow direction. S ACK Command Byte: selects which register you are writing to. Slave Address S COMMAND 8 Bits Slave Address FIGURE 5-1: SMBus Protocols Data Byte: reads from the register set by the command byte. SMBus Protocol: Read Byte Format. ADDRESS 7 Bits DATA NACK P Data Byte: reads data from the register commanded by the last Read Byte or Write Byte transmission SMBus Protocol: Receive Byte Format. S = Start Condition P = Stop Condition Shaded = Slave Transmission DS20001734C-page 16 ACK 8 Bits Slave Address FIGURE 5-3: RD ACK = Acknowledge = 0 NACK = Not Acknowledged = 1 WR = Write = 0 RD = Read = 1 2002-2014 Microchip Technology Inc. TC654/TC655 6.0 REGISTER SET The TC654/TC655 devices contain 9 registers that provide a variety of data and functionality control to the outside system. These registers are listed below in Table 6-1. Of key importance is the command byte information, which is needed in the read and write protocols in order to select the individual registers. TABLE 6-1: COMMAND BYTE ASSIGNMENTS Command Read Write POR Default State RPM1 Register 0000 0000 X — 0 0000 0000 RPM Output 1 RPM2 0000 0001 X — 0 0000 0000 RPM Output 2 FAN_FAULT1 0000 0010 X X 0000 1010 Fan Fault 1 Threshold FAN_FAULT2 0000 0011 X X 0000 1010 Fan Fault 2 Threshold CONFIG 0000 0100 X X 0000 1010 Configuration STATUS 0000 0101 X — 00X0 0X00 Status. See Section 6.4 “Status Register (Status)”, Status Register explanation of X DUTY_CYCLE 0000 0110 X X 0000 0010 Fan Speed Duty Cycle MFR_ID 0000 0111 X — 0101 0100 Manufacturer Identification VER_ID 0000 1000 X — 0000 000X Version Identification: (X = ‘0’ TC654, X = ‘1’ TC655) 6.1 RPM-OUTPUT1 & RPM-OUTPUT2 Registers (RPM1 & RPM2) As discussed in Section 4.7 “Sensing Fan Operation (SENSE1 & SENSE2)”, fan current pulses are detected at the SENSE1 and SENSE2 inputs of the TC654/ TC655 device. The current pulse information is used to calculate the fan RPM. The fan RPM data for fans 1 and 2 is then written to registers RPM1 and RPM2, respectively. RPM1 and RPM2 are 9-bit registers that provide REGISTER 6-1: Function the RPM information in 50 RPM (8-bit) or 25 RPM (9bit) increments. This is selected via RES (bit 6<0>) in the Configuration Register, with ‘0’ = 50 RPM and ‘1’ = 25 RPM. The default state is zero (50 RPM). The maximum fan RPM value that can be read is 12775 RPM. If this value is exceeded, R2CO (bit 4<0>) and R1CO (bit 3<0>) in the Status Register will be set to a '1' to indicate that a counter overflow of the respective RPM register has occurred. Register 6-1 shows the RPM output register 9-bit format. RPM OUTPUT REGISTERS (RPM1 & RPM2) D(8) D(7) D(6) D(5) D(4) D(3) D(2) D(1) D(0) RPM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 25 0 0 0 0 0 0 0 1 0 50 . . . . . . . . . . . . . . . . . . 1 1 1 1 1 1 1 1 0 12750 1 1 1 1 1 1 1 1 1 12775 2002-2014 Microchip Technology Inc. DS20001734C-page 17 TC654/TC655 6.2 FAN_FAULT1 & FAN_FAULT2 Threshold Registers (FAN_FAULT1 & FAN_ FAULT2) in RPM1 and RPM2 Registers) drops below the value that is set in the Fan Fault Registers for more than 2.4sec, a fan fault indication will be given. F1F (bit 0<0>) and F2F (bit 1<0>) in the Status Register indicate fan fault conditions for fan 1 and fan 2, respectively. The FAULT output will also be pulled low in a fan fault condition. Changing FFCLR (bit 7<0>) in the Configuration Register will reset the fan fault bits in the Status Register as well as the FAULT output. See Register 6-2 for the Fan Fault Threshold Register 8-bit format. The Fan Fault Threshold Registers (FAN_FAULT1 and FAN_ FAULT2) are used to set the fan fault threshold levels for fan 1 and fan 2, respectively. The Fan Fault Registers are 8-bit, read/writable registers that allow the fan fault RPM threshold to be set in 50 RPM increments. The default setting for both Fan Fault registers is 500 RPM (0000 1010). The maximum set point value is 12750 RPM. If the measured fan RPM (stored REGISTER 6-2: FAN FAULT THRESHOLD REGISTERS (FAN_FAULT1 & FAN_FAULT2) D(7) D(6) D(5) D(4) D(3) D(2) D(1) D(0) RPM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 50 0 0 0 0 0 0 1 0 100 . . . . . . . . . . . . . . . . 1 1 1 1 1 1 1 0 12700 1 1 1 1 1 1 1 1 12750 DS20001734C-page 18 2002-2014 Microchip Technology Inc. TC654/TC655 6.3 CONFIGURATION REGISTER (CONFIG) VOUT duty cycle (fan speed) control method, select the fan current pulses per rotation for fans 1 and 2 (for fan RPM calculation) and put the TC654/TC655 device into a Shutdown mode to save power consumption. See Register 6-3 below for the Configuration Register bit descriptions. The Configuration Register is an 8-bit read/writable multi-function control register. This register allows the user to clear fan faults, select RPM resolution, select REGISTER 6-3: CONFIGURATION REGISTER (CONFIG) R/W-0 R/W-0 R/W-0 R/W-0 R/W-1 R/W-0 R/W-1 R/W-0 FFCLR RES DUTYC F2PPR F2PPR F1PPR F1PPR SDM bit 7 bit 0 bit 7 FFCLR: Fan Fault Clear 1 = Clear Fan Fault. This will reset the Fan Fault bits in the Status Register and the FAULT output. 0 = Normal Operation (default) bit 6 RES: Resolution Selection for RPM Output Registers 1 = RPM Output Registers (RPM1 and RPM2) will be set for 25 RPM (9-bit) resolution. 0 = RPM Output Registers (RPM1 and RPM2) will be set for 50 RPM (8-bit) resolution. (default) bit 5 DUTYC: Duty Cycle Control Method 1 = The VOUT duty cycle will be controlled via the SMBus interface. The value for the VOUT duty cycle will be taken from the duty cycle register (DUTY_CYCLE). 0 = The VOUT duty cycle will be controlled via the VIN analog input pin. The VOUT duty cycle value will be between 30% and 100% for VIN values between 1.62V and 2.6V typical. If the VIN pin is open when this mode is selected, the VOUT duty cycle will default to 39.33%. (default) bit 4-3 F2PPR: Fan 2 Pulses Per Rotation The TC654/TC655 device uses this setting to understand how many current pulses per revolution Fan 2 should have. It then uses this as part of the calculation for the fan 2 RPM value in the RPM2 Register. See Section 7.7 “Determining Current Pulses Per Revolution of Fans” for application information on determining your fan’s number of current pulses per revolution. 00 = 1 01 = 2 (default) 10 = 4 11 = 8 bit 2-1 F1PPR: Fan 1 Pulses Per Rotation The TC654/TC655 device uses this setting to understand how many current pulses per revolution Fan 1 should have. It then uses this as part of the calculation for the fan 1 RPM value for the RPM1 Register. See Section 7.7 “Determining Current Pulses Per Revolution of Fans” for application information on determining your fan’s number of current pulses per revolution. 00 = 1 01 = 2 (default) 10 = 4 11 = 8 bit 0 SDM: Shutdown Mode 1 = Shutdown mode. See Section 4.9 “Low-Power Shutdown Mode” for more information on lowpower Shutdown mode. 0 = Normal operation. (default) Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared 2002-2014 Microchip Technology Inc. x = Bit is unknown DS20001734C-page 19 TC654/TC655 6.4 STATUS REGISTER (STATUS) and over-temperature indication are all available in the Status register. The Status register is an 8-bit ReadOnly register with bits 6 and 7 unused. See Register 64 below for the bit descriptions. The Status register provides all the information about what is going on within the TC654/TC655 devices. Fan fault information, VIN status, RPM counter overflow, REGISTER 6-4: STATUS REGISTER (STATUS) U-0 U-0 R-X R-0 R-0 R-X R-0 R-0 — — OTF R2CO R1CO VSTAT F2F F1F bit 7 bit 0 bit 7-6 Unimplemented: Read as ‘0’ bit 5 OTF: Over-Temperature Fault Condition For the TC654/TC655 device, this bit is set to the proper state immediately at start-up and is therefore treated as an unknown (X). If VIN is greater than the threshold required for 100% duty cycle on VOUT (2.6V typical), then the bit will be set to a ‘1’. If it is less than the threshold, the bit will be set to ‘0’. This is determined at power-up. 1 = Over-Temperature condition has occurred. 0 = Normal operation. VIN is less than 2.6V. bit 4 R2CO: RPM2 Counter Overflow 1 = Fault condition. The maximum RPM reading of 12775 RPM in register RPM2 has been exceeded. This bit will automatically reset to zero when the RPM reading comes back into range. 0 = Normal operation. RPM reading is within limits (default). bit 3 R1CO: RPM1 Counter Overflow 1 = Fault condition. The maximum RPM reading of 12775 RPM in register RPM1 has been exceeded. This bit will automatically reset to zero when the RPM reading comes back into range. 0 = Normal operation. RPM reading is within limits (default). bit 2 VSTAT: VIN Input Status For the TC654/TC655 devices, the VIN pin status is checked immediately at power-up. If no external thermistor or voltage output network is connected (VIN is open), this bit is set to a ‘1’. If an external network is detected, this bit is set to ‘0’. If the VIN pin is open and SMBus operation has not been selected in the Configuration Register, the VOUT duty cycle will default to 39.33%. 1 = VIN is open. 0 = Normal operation. voltage present at VIN. bit 1 F2F: Fan 2 Fault 1 = Fault Condition. The value for fan RPM in the RPM2 Register has fallen below the value set in the FAN_FAULT2 Threshold Register. The speed of Fan 2 is too low and a fault condition is being indicated. The FAULT output will be pulled low at the same time. This fault bit can be cleared using the Fan Fault Clear bit (FFCLR (bit 7<0>)) in the Configuration Register. 0 = Normal Operation (default). bit 0 F1F: Fan 1 Fault 1 = Fault Condition. The value for fan RPM in the RPM1 Register has fallen below the value set in the FAN_FAULT1 Threshold Register. The speed of Fan 1 is too low and a fault condition is being indicated. The FAULT output will be pulled low at the same time. This fault bit can be cleared using the Fan Fault Clear bit (FFCLR (bit 7<0>)) in the Configuration Register. 0 = Normal Operation (default). Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared DS20001734C-page 20 x = Bit is unknown 2002-2014 Microchip Technology Inc. TC654/TC655 6.5 DUTY-CYCLE Register (DUTY_CYCLE) The DUTY_CYCLE register is a 4-bit read/writable register used to control the duty cycle of the VOUT output. The controllable duty cycle range via this register is 30% to 100%, with programming steps of 4.67%.This method of duty cycle control is mainly used with the SMBus interface. However, if the VIN method of duty cycle control has been selected (or defaulted to), and the VIN pin is open, the duty cycle will go to the default setting of this register, which is 0010 (39.33%). The duty cycle settings are shown in Register 6-5. REGISTER 6-5: DUTY-CYCLE REGISTER (DUTY_CYCLE) D(3) D(2) D(1) D(0) 0 0 0 0 30% 0 0 0 1 34.67% 0 0 1 0 39.33% (default for VIN open and when SMBus is not selected) Duty-Cycle 0 0 1 1 44% 0 1 0 0 48.67% 0 1 0 1 53.33% 0 1 1 0 58% 0 1 1 1 62.67% 1 0 0 0 67.33% 1 0 0 1 72% 1 0 1 0 76.67% 1 0 1 1 81.33% 1 1 0 0 86% 1 1 0 1 90.67% 1 1 1 0 95.33% 1 1 1 1 100% 2002-2014 Microchip Technology Inc. 6.6 Manufacturer’s Identification Register (MFR_ID) This register allows the user to identify the manufacturer of the part. The MFR_ID register is an 8-bit ReadOnly register. See Register 6-6 for the Microchip manufacturer ID. REGISTER 6-6: MANUFACTURER’S IDENTIFICATION REGISTER (MFR_ID) D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0] 0 1 0 1 0 1 0 0 6.7 Version ID Register (VER_ID) This register is used to indicate which version of the device is being used, either the TC654 or the TC655. This register is a simple 2-bit Read-Only register. REGISTER 6-7: D[1] VERSION ID REGISTER (VER_ID) D[0] Version 0 0 TC654 0 1 TC655 DS20001734C-page 21 TC654/TC655 7.0 APPLICATIONS INFORMATION 7.1 Connecting to the SMBus SDA SCLK PIC16F876 Microcontroller The SMBus is an open-collector bus, requiring pull-up resistors connected to the SDA and SCLK lines. This configuration is shown in Figure 7-1. 24LC01 EEPROM TC654/TC655 Fan Speed Controller PIC® Microcontroller VDD R R TCN75 Temperature Sensor TC654/TC655 SDA SCLK FIGURE 7-2: 7.2 Range for R: 13.2 kto 46 k for VDD = 5.0V FIGURE 7-1: SMBus. Pull-up Resistors On The number of devices connected to the bus is limited only by the maximum rise and fall times of the SDA and SCLK lines. Unlike I2C specifications, SMBus does not specify a maximum bus capacitance value. Rather, the SMBus specification calls out that the maximum current through the pull-up resistor be 350 µA (minimum, 100 µA, is also specified). Therefore, the value of the pull-up resistors will vary depending on the system’s bias voltage, VDD. Minimizing bus capacitance is still very important as it directly affects the rise and fall times of the SDA and SCLK lines. The range for pull-up resistor values for a 5V system are shown in Figure 7-1. Although SMBus specifications only require the SDA and SCLK lines to pull down 350 µA, with a maximum voltage drop of 0.4V, the TC654/TC655 has been designed to meet a maximum voltage drop of 0.4V, with 3 mA of current. This allows lower values of pull-up resistors to be used, which will allow higher bus capacitance. If this is to be done, though, all devices on the bus must be able to meet the same pull-down current requirements as well. A possible configuration using multiple devices on the SMBus is shown in Figure 7-2. Multiple Devices on SMBus. Setting the PWM Frequency The PWM frequency of the VOUT output is set by the capacitor value attached to the CF pin. The PWM frequency will be 30 Hz (typical) for a 1 µF capacitor. The relationship between frequency and capacitor value is linear, making alternate frequency selections easy. As stated in previous sections, the PWM frequency should be kept in the range of 15 Hz to 35 Hz. This will eliminate the possibility of having audible frequencies when varying the duty cycle of the fan drive. A very important factor to consider when selecting the PWM frequency for the TC654/TC655 devices is the RPM rating of the selected fan and the minimum duty cycle for operation. For fans that have a full-speed rating of 3000 RPM or less, it is desirable to use a lower PWM frequency. A lower PWM frequency allows for a longer time period to monitor the fan current pulses. The goal is to be able to monitor at least two fan current pulses during the on time of the VOUT output. Example: Your system design requirement is to operate the fan at 50% duty cycle when ambient temperatures are below 20°C. The fan full-speed RPM rating is 3000 RPM and has four current pulses per rotation. At 50% duty cycle, the fan will be operating at approximately 1500 RPM. EQUATION 60 1000 Time for one revolution (msec.) = ------------------------ = 40 1500 If one fan revolution occurs in 40 msec, then each fan pulse occurs 10 msec apart. In order to detect two fan current pulses, the on time of the VOUT pulse must be at least 20 msec. With the duty cycle at 50%, the total period of one cycle must be at least 40 msec, which makes the PWM frequency 25 Hz. For this example, a PWM frequency of 20 Hz is recommended. This would define a CF capacitor value of 1.5 µF. DS20001734C-page 22 2002-2014 Microchip Technology Inc. TC654/TC655 7.3 Temperature Sensor Design As discussed in previous sections, the VIN analog input has a range of 1.62V to 2.6V (typical), which represents a duty cycle range on the VOUT output of 30% to 100%, respectively. The VIN voltages can be thought of as representing temperatures. The 1.62V level is the low temperature at which the system only requires 30% fan speed for proper cooling. The 2.6V level is the high temperature, for which the system needs maximum cooling capability. Therefore, the fan needs to be at 100% speed. One of the simplest ways of sensing temperature over a given range is to use a thermistor. By using an NTC thermistor as shown in Figure 7-3, a temperature variant voltage can be created. EQUATION V DD R 2 V t1 = ---------------------------------------RTEMP t1 + R 2 V DD R 2 V t2 = ---------------------------------------RTEMP t2 + R 2 In order to solve for the values of R1 and R2, the values for VIN and the temperatures at which they are to occur need to be selected. The variables, t1 and t2, represent the selected temperatures. The value of the thermistor at these two temperatures can be found in the thermistor data sheet. With the values for the thermistor and the values for VIN, you now have two equations from which the values for R1 and R2 can be found. Example: The following design goals are desired: VDD • Duty Cycle = 50% (VIN = 1.9V) with Temperature (t1) = 30°C • Duty Cycle = 100% (VIN = 2.6V) with Temperature (t2) = 60°C IDIV Using a 100 k thermistor (25°C value), we look up the thermistor values at the desired temperatures: There are many values that can be chosen for the NTC thermistor. There are also thermistors which have a linear resistance instead of logarithmic, which can help to eliminate R1. If less current draw from VDD is desired, then a larger value thermistor should be chosen. The voltage at the VIN pin can also be generated by a voltage output temperature sensor device. The key is to get the desired VIN voltage to system (or component) temperature relationship. The following equations apply to the circuit in Figure 7-3. 2002-2014 Microchip Technology Inc. 4.000 140000 3.500 VIN Voltage 120000 2.500 80000 2.000 60000 NTC Thermistor 100K @ 25ºC 40000 20000 VIN (V) 3.000 100000 1.500 1.000 0.500 RTEMP 0 10 90 0.000 80 0 70 Figure 7-3 represents a temperature dependent voltage divider circuit. Rt is a conventional NTC thermistor, R1 and R2 are standard resistors. R1 and Rt form a parallel resistor combination that will be referred to as RTEMP (RTEMP = R1 * Rt/ R1 + Rt). As the temperature increases, the value of Rt decreases and the value of RTEMP will decrease with it. Accordingly, the voltage at VIN increases as temperature increases, giving the desired relationship for the VIN input. The purpose of R1 is to help linearize the response of the sensing network. Figure 7-4 shows an example of this. 60 Temperature Sensing • R1 = 34.8 k • R2 = 14.7 k 50 FIGURE 7-3: Circuit. Substituting these numbers into the given equations, we come up with the following numbers for R1 and R2. 40 R2 • Rt = 79428 @ 30°C • Rt = 22593 @ 60°C 30 VIN 20 R1 Network Resistance () Rt Temperature (ºC) FIGURE 7-4: How Thermistor Resistance, VIN, And RTEMP Vary With Temperature. Figure 7-4 graphs three parameters versus temperature. They are Rt, R1 in parallel with Rt, and VIN. As described earlier, you can see that the thermistor has a logarithmic resistance variation. When put in parallel with R1, though, the combined resistance becomes more linear, which is the desired effect. This gives us the linear looking curve for VIN. DS20001734C-page 23 TC654/TC655 7.4 FanSense Network (RSENSE & CSENSE) The network comprised of RSENSE and CSENSE allows the TC654/TC655 devices to detect commutation of the fan motor. RSENSE converts the fan current into a voltage. CSENSE AC couples this voltage signal to the SENSE pins (SENSE1 and SENSE2). The goal of the SENSE network is to provide a voltage pulse to the SENSE pin that has a minimum amplitude of 120 mV. This will ensure that the current pulse caused by the fan commutation is recognized by the TC654/TC655 device. A 0.1 µF ceramic capacitor is recommended for CSENSE. Smaller values will require larger sense resistors be used. Using a 0.1 µF capacitor results in reasonable values for RSENSE. Figure 7-5 illustrates a typical SENSE network. FAN 1 TABLE 7-1: RSENSE VS. FAN CURRENT Nominal Fan Current (mA) RSENSE (ohm) 50 9.1 100 4.7 150 3.0 200 2.4 250 2.0 300 1.8 350 1.5 400 1.3 450 1.2 500 1.0 Figure 7-6 shows some typical waveforms for the fan current and the voltage at the Sense pins. FAN 2 RISO1 715 RISO2 VOUT 715 SENSE1 CSENSE1 (0.1 µF typical) RSENSE1 SENSE2 CSENSE2 (0.1 µF typical) Note: RSENSE2 See Table 7-1 for RSENSE1 and RSENSE2 values. FIGURE 7-5: FIGURE 7-6: Typical Fan Current and Sense Pin Waveforms. Typical Sense Network. The value of RSENSE will change with the current rating of the fan. A key point is that the current rating of the fan specified by the manufacturer may be a worst case rating. The actual current drawn by the fan may be lower than this rating. For the purposes of setting the value for RSENSE, the operating fan current should be measured. Table 7-1 shows values of RSENSE according to the nominal operating current of the fan. The fan currents are average values. If the fan current falls between two of the values listed, use the higher resistor value. 7.5 Output Drive Device Selection The TC654/TC655 is designed to drive two external NPN transistors or two external N-channel MOSFETs as the fan speed modulating elements. These two arrangements are shown in Figure 7-7. For lower current fans, NPN transistors are a very economical choice for the fan drive device. It is recommended that, for higher-current fans (500 mA and above), MOSFETs be used as the fan drive device. Table 7-2 provides some possible part numbers for use as the fan drive element. When using an NPN transistor as the fan drive element, a base current limiting resistor must be used. This is shown in Figure 7-7. When using MOSFETs as the fan drive element, it is very easy to turn the MOSFETs on and off at very high rates. Because the gate capacitances of these small DS20001734C-page 24 2002-2014 Microchip Technology Inc. TC654/TC655 MOSFETs are very low, the TC654/TC655 can charge and discharge them very quickly, leading to very fast edges. Of key concern is the turn-off edge of the MOSFET. Since the fan motor winding is essentially an inductor, once the MOSFET is turned off, the current that was flowing through the motor wants to continue to flow. If the fan does not have internal clamp diodes around the windings of the motor, there is no path for this current to flow through, and the voltage at the drain of the MOSFET may rise until the drain to source rating of the MOSFET is exceeded. This will most likely cause the MOSFET to go into Avalanche mode. Since there is very little energy in this occurrence, it will probably not fail the device, but it would be a long term reliability issue. The following is recommended: • Ask how the fan is designed. If the fan has clamp diodes internally, you will not experience this problem. If the fan does not have internal clamp diodes, it is a good idea to put one externally (Figure 7-8). You can also put a resistor between VOUT and the gate of the MOSFET, which will help slow down the turn-off and limit this condition. VDD VDD FAN FAN RBASE VOUT Q1 Q1 VOUT RSENSE RSENSE GND GND a) Single Bipolar Transistor FIGURE 7-7: TABLE 7-2: Device MMBT2222A b) N-Channel MOSFET Output Drive Device Configurations. FAN DRIVE DEVICE SELECTION TABLE (Note 2) Package Max Vbe sat / Vgs(V) Min hfe Vce/VDS Fan Current (mA) Suggested Rbase (ohms) SOT-23 1.2 50 40 150 800 MPS2222A TO-92 1.2 50 40 150 800 MPS6602 TO-92 1.2 50 40 500 301 SI2302 SOT-23 2.5 NA 20 500 Note 1 MGSF1N02E SOT-23 2.5 NA 20 500 Note 1 SI4410 SO-8 4.5 NA 30 1000 Note 1 SI2308 SOT-23 4.5 NA 60 500 Note 1 Note 1: A series gate resistor may be used in order to control the MOSFET turn-on and turn-off times. 2: These drive devices are suggestions only. Fan currents listed are for individual fans. 2002-2014 Microchip Technology Inc. DS20001734C-page 25 TC654/TC655 The first piece of information required is the fan's fullspeed RPM rating. The fan RPM rating can then be converted to give the time for one revolution using the following equation: FAN EQUATION 60 1000 Time for one revolution (msec.) = -----------------------Fan RPM Q1 VOUT RSENSE GND Q1- N-Channel MOSFET FIGURE 7-8: Off. 7.6 Clamp Diode For Fan Turn- Bias Supply Bypassing and Noise Filtering The fan current can now be monitored over this time period. The number of pulses occurring in this time period is the fan's "Current Pulses per Rotation" rating which is needed in order to accurately read fan RPM. Example: The full-speed fan RPM rating is 8200 RPM. From this, the time for one fan revolution is calculated to be 7.3 msec, using the previously discussed equation. Using a current probe, the fan current can be monitored as the fan is operating at full speed. Figure 7-9 shows the fan current pulses for this example. The 7.44 msec window, marked by the cursors, is very near the 7.3 msec calculated above, and is within the tolerance of the fan ratings. Four current pulses occur within this 7.44 msec time frame. Given this information, F2PPR (bits 4-3<01>) and F1PPR (bits 2-1<01>) in the Configuration Register, should be set to '10' to indicate 4 current pulses per revolution. The bias supply (VDD) for the TC654/TC655 devices should be bypassed with a 1 µF ceramic capacitor. This capacitor will help supply the peak currents that are required to drive the base/gate of the external fan drive devices. As the VIN pin controls the duty cycle in a linear fashion, any noise on this pin can cause duty cycle jittering. For this reason, the VIN pin should be bypassed with a 0.01 µF capacitor. In order to keep fan noise off of the TC654/TC655 device ground, individual ground returns for the TC654/ TC655 and the low side of the fan current sense resistor should be used. 7.7 Determining Current Pulses Per Revolution of Fans There are many different fan designs available in the marketplace today. The motor designs can vary and, along with it, the number of current pulses in one fan revolution. In order to correctly measure and communicate the fan speed, the TC654/TC655 must be programmed for the proper number of fan current pulses per revolution. This is done by setting the F2PPR and F1PPR bits in the Configuration Register to the proper values (see Section 6.3 “Configuration Register (Config)” for settings). A fan's current pulses per revolution can be determined in the following manner. DS20001734C-page 26 FIGURE 7-9: Revolution Fan. 7.8 Four Current Pulses Per How to Eliminate False Current Pulse Sensing During the PWM mode of operation, some fans will generate an extra current pulse. This pulse occurs when the external drive device is turned on and is, in most cases, caused by the fan's electronics that control the fan motor. This pulse does not represent true fan current and needs to be blanked out. This is particularly important for detecting a fan in a locked rotor condition. Figure 7-10 shows the voltage pulse at the Sense pin, 2002-2014 Microchip Technology Inc. TC654/TC655 which is caused by the fan's "extra" current pulse during PWM output turn-on. FAN 1 FAN 2 RISO1 CSLOW1 (0.1uF typical) Sense Pin Voltage "Extra Pulse" RISO2 VOUT CSLOW2 SENSE1 TC654/ TC655 VOUT PWM Extra Pulse at Sense Pin. This problem occurs mainly with fans that have a current waveshape like the one shown in Figure 7-9. For configurations where an NPN transistor is being used as the external drive device, the typical RSENSE and CSENSE scheme can continue to be used to sense the fan current pulses. In order to eliminate the extra current pulse, a slow-down capacitor can be placed from the base of the transistor to ground. A 0.1 µF capacitor is appropriate in most cases. This arrangement is shown in Figure 7-11. This capacitor will help to slow down the turn-on edge of the transistor and reduce the amplitude of the extra current pulse. For configurations using an N-channel MOSFET as the drive device, the slow-down capacitor does not fix all conditions and the current sensing scheme must be changed. Since the current for this type of fan always returns to zero, the coupling capacitor (CSENSE) is not needed. Instead, it will be replaced by an R-C configuration to eliminate the voltage pulse generated by the extra current pulse. This new sensing configuration is shown in Figure 7-12. The values of the resistor/capacitor combination should be adjusted so that the voltage pulse generated by the extra current pulse is smoothed and is not registered by the TC654/TC655 as a true fan current pulse. Typical values for RSLOW and CSLOW are 1 K and 1000 pF, respectively. 2002-2014 Microchip Technology Inc. (0.1 µF typical) RSENSE1 SENSE2 CSENSE2 (0.1 µF typical) GND FIGURE 7-10: CSENSE (0.1 µF typical) FIGURE 7-11: Capacitor. RSENSE2 Transistor Drive with CSLOW FAN 1 FAN 2 VOUT RSLOW1 (1 k typical) SENSE1 TC654/ TC655 CSLOW1 (1000pF typical) RSENSE1 RSLOW2 (1 k typical) SENSE2 GND CSLOW2 (1000pF typical) RSENSE2 FIGURE 7-12: FET Drive with RSLOW/ CSLOW Sense Scheme. DS20001734C-page 27 TC654/TC655 8.0 PACKAGING INFORMATION 8.1 Package Marking Information 10-Lead MSOP (3x3 mm) Example TC654E 135256 Legend: XX...X Y YY WW NNN e3 * Note: DS20001734C-page 28 Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC® designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package. In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. 2002-2014 Microchip Technology Inc. TC654/TC655 UN Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging 2002-2014 Microchip Technology Inc. DS20001734C-page 29 TC654/TC655 UN Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging DS20001734C-page 30 2002-2014 Microchip Technology Inc. TC654/TC655 10-Lead Plastic Micro Small Outline Package (UN) [MSOP] Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging 2002-2014 Microchip Technology Inc. DS20001734C-page 31 TC654/TC655 NOTES: DS20001734C-page 32 2002-2014 Microchip Technology Inc. TC654/TC655 APPENDIX A: REVISION HISTORY Revision C (July 2014) The following is the list of modifications. 1. 2. Updated the package marking drawing. Added Appendix A. Revision B (January 2013) The following is the list of modifications. 1. Added a note to the package outline drawing. Revision A (2002) • Original Release of this Document. 2002-2014 Microchip Technology Inc. DS20001734C-page 33 TC654/TC655 NOTES: DS20001734C-page 34 2002-2014 Microchip Technology Inc. TC654/TC655 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. Device X /XX Temperature Range Device: TC654: TC654T: TC655: TC655T: Package PWM Fan Speed Controller w/Fault Detection PWM Fan Speed Controller w/Fault Detection (Tape and Reel) PWM Fan Speed Controller w/Fault Detection PWM Fan Speed Controller w/Fault Detection (Tape and Reel) Temperature Range: E Package: UN = Plastic Micro Small Outline (MSOP), 10-lead Examples: a) TC654EUN: PWM Fan Speed Controller w/ Fault Detection b) TC654EUNT: PWM Fan Speed Controller w/Fault Detection (Tape and Reel) c) TC655EUN: PWM Fan Speed Controller w/ Fault Detection d) TC655EUNT: PWM Fan Speed Controller w/Fault Detection (Tape and Reel) = -40C to +85C 2002-2014 Microchip Technology Inc. DS20001734C-page35 TC654/TC655 NOTES: DS20001734C-page 36 2002-2014 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, dsPIC, FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer, LANCheck, MediaLB, MOST, MOST logo, MPLAB, OptoLyzer, PIC, PICSTART, PIC32 logo, RightTouch, SpyNIC, SST, SST Logo, SuperFlash and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. The Embedded Control Solutions Company and mTouch are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet, KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code Generation, PICDEM, PICDEM.net, PICkit, PICtail, RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total Endurance, TSHARC, USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries. GestIC is a registered trademarks of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in other countries. All other trademarks mentioned herein are property of their respective companies. © 2002-2014, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. ISBN: 978-1-63276-362-4 QUALITY MANAGEMENT SYSTEM CERTIFIED BY DNV == ISO/TS 16949 == 2002-2014 Microchip Technology Inc. Microchip received ISO/TS-16949:2009 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. DS20001734C-page 37 Worldwide Sales and Service AMERICAS ASIA/PACIFIC ASIA/PACIFIC EUROPE Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://www.microchip.com/ support Web Address: www.microchip.com Asia Pacific Office Suites 3707-14, 37th Floor Tower 6, The Gateway Harbour City, Kowloon Hong Kong Tel: 852-2943-5100 Fax: 852-2401-3431 India - Bangalore Tel: 91-80-3090-4444 Fax: 91-80-3090-4123 Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 Australia - Sydney Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 Atlanta Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455 China - Beijing Tel: 86-10-8569-7000 Fax: 86-10-8528-2104 Austin, TX Tel: 512-257-3370 China - Chengdu Tel: 86-28-8665-5511 Fax: 86-28-8665-7889 Boston Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088 Chicago Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075 Cleveland Independence, OH Tel: 216-447-0464 Fax: 216-447-0643 Dallas Addison, TX Tel: 972-818-7423 Fax: 972-818-2924 Detroit Novi, MI Tel: 248-848-4000 Houston, TX Tel: 281-894-5983 Indianapolis Noblesville, IN Tel: 317-773-8323 Fax: 317-773-5453 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 New York, NY Tel: 631-435-6000 San Jose, CA Tel: 408-735-9110 Canada - Toronto Tel: 905-673-0699 Fax: 905-673-6509 DS20001734C-page 38 China - Chongqing Tel: 86-23-8980-9588 Fax: 86-23-8980-9500 China - Hangzhou Tel: 86-571-8792-8115 Fax: 86-571-8792-8116 China - Hong Kong SAR Tel: 852-2943-5100 Fax: 852-2401-3431 China - Nanjing Tel: 86-25-8473-2460 Fax: 86-25-8473-2470 China - Qingdao Tel: 86-532-8502-7355 Fax: 86-532-8502-7205 China - Shanghai Tel: 86-21-5407-5533 Fax: 86-21-5407-5066 China - Shenyang Tel: 86-24-2334-2829 Fax: 86-24-2334-2393 China - Shenzhen Tel: 86-755-8864-2200 Fax: 86-755-8203-1760 China - Wuhan Tel: 86-27-5980-5300 Fax: 86-27-5980-5118 China - Xian Tel: 86-29-8833-7252 Fax: 86-29-8833-7256 India - New Delhi Tel: 91-11-4160-8631 Fax: 91-11-4160-8632 France - Paris Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 India - Pune Tel: 91-20-3019-1500 Japan - Osaka Tel: 81-6-6152-7160 Fax: 81-6-6152-9310 Germany - Dusseldorf Tel: 49-2129-3766400 Germany - Munich Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 Japan - Tokyo Tel: 81-3-6880- 3770 Fax: 81-3-6880-3771 Germany - Pforzheim Tel: 49-7231-424750 Korea - Daegu Tel: 82-53-744-4301 Fax: 82-53-744-4302 Italy - Milan Tel: 39-0331-742611 Fax: 39-0331-466781 Korea - Seoul Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934 Italy - Venice Tel: 39-049-7625286 Malaysia - Kuala Lumpur Tel: 60-3-6201-9857 Fax: 60-3-6201-9859 Netherlands - Drunen Tel: 31-416-690399 Fax: 31-416-690340 Malaysia - Penang Tel: 60-4-227-8870 Fax: 60-4-227-4068 Poland - Warsaw Tel: 48-22-3325737 Philippines - Manila Tel: 63-2-634-9065 Fax: 63-2-634-9069 Singapore Tel: 65-6334-8870 Fax: 65-6334-8850 Taiwan - Hsin Chu Tel: 886-3-5778-366 Fax: 886-3-5770-955 Spain - Madrid Tel: 34-91-708-08-90 Fax: 34-91-708-08-91 Sweden - Stockholm Tel: 46-8-5090-4654 UK - Wokingham Tel: 44-118-921-5800 Fax: 44-118-921-5820 Taiwan - Kaohsiung Tel: 886-7-213-7830 Taiwan - Taipei Tel: 886-2-2508-8600 Fax: 886-2-2508-0102 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350 China - Xiamen Tel: 86-592-2388138 Fax: 86-592-2388130 China - Zhuhai Tel: 86-756-3210040 Fax: 86-756-3210049 03/25/14 2002-2014 Microchip Technology Inc.