EVALUATION KIT AVAILABLE MAX31790 6-Channel PWM-Output Fan RPM Controller General Description Features The MAX31790 controls the speeds of up to six fans using six independent PWM outputs. The desired fan speeds (or PWM duty cycles) are written through the I2C interface. The outputs drive “4-wire” fans directly, or can be used to modulate the fan’s power terminals using an external pass transistor.
MAX31790 6-Channel PWM-Output Fan RPM Controller ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC, SDA, SCL, ADD0, ADD1, FAN_FAIL, PWMOUTn Relative to GND............-0.3V to +6.0V Voltage Range on TACHn, WD_START, SPIN_START, FREQ_START, CLKOUT, FULL_SPEED, PWM_STARTn Relative to GND...............-0.3V to VCC + 0.3V (not to exceed +6.0V) Input Current at Any Pin..................................................... +5mA Package Input Current.....................................................
MAX31790 6-Channel PWM-Output Fan RPM Controller FAN CONTROL CHARACTERISTICS (TA = -40°C to +125°C, typical values are VCC = 3.3V, TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL CONDITIONS MAX UNITS 9 9 Bits PWM Frequency Accuracy -6 +6 % TACH Count Resolution 11 11 Bits PWM Resolution TACH Count Oscillator and CLKOUT Clock TACH Count Oscillator and CLKOUT Accuracy (Note 7) TACH Minimum Input Pulse Width fTOSC fERR:TOSC tTACHMIN MIN (Note 7) TYP 32.
MAX31790 6-Channel PWM-Output Fan RPM Controller I2C AC ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.0V to +5.5V, TA = -40°C to +125°C, timing referenced to VIL(MAX) and VIH(MIN), unless otherwise noted.) (Notes 3, 8) (Figure 1) PARAMETER SYMBOL Maximum Receive SCL/SDA Fall Time CONDITIONS MIN TYP tF (Note 10) 300 ns Minimum Receive SCL/SDA Fall Time tF (Note 10) 20 + 0.
MAX31790 6-Channel PWM-Output Fan RPM Controller SDA tBUF tF tLOW tSP tHD:STA SCL tHD:STA tHIGH tR tSU:STA tHD:DAT STOP tSU:STO tSU:DAT START REPEATED START NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN). Figure 1. I2C Timing Diagram Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) MAX31790 toc01 4 3 PWM FREQUENCY = 25kHz SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 4 POWER-SUPPLY CURRENT vs. TEMPERATURE 1.47kHz 2 1 MAX31790 toc02 POWER-SUPPLY CURRENT vs.
MAX31790 6-Channel PWM-Output Fan RPM Controller Pin Configuration VCC PWMOUT1 TACH1 PWMOUT2 TACH2 PWMOUT3 TACH3 TOP VIEW 21 20 19 18 17 16 15 SDA 22 14 PWMOUT4 SCL 23 13 TACH4 12 PWMOUT5 11 TACH5 10 PWMOUT6 9 TACH6 8 GND FAN_FAIL 24 MAX31790 PWM_START0 25 PWM_START1 26 FULL_SPEED 27 EP + 4 5 6 7 WD_START XTAL2 XTAL1 SPIN_START 3 ADD0 2 ADD1 1 FREQ_START CLKOUT 28 TQFN (4mm x 4mm) Pin Description PIN NAME FUNCTION 1 FREQ_START This input is sampled at
MAX31790 6-Channel PWM-Output Fan RPM Controller Pin Description (continued) PIN NAME 9 TACH6 11 TACH5 13 TACH4 15 TACH3 17 TACH2 19 TACH1 10 PWMOUT6 12 PWMOUT5 14 PWMOUT4 16 PWMOUT3 18 PWMOUT2 20 PWMOUT1 FUNCTION Logic/Analog Inputs for Tach Signals. If a fan has a logic tach output, it can be used for RPM control. For a 2-wire fan, analog input can be used for fan-failure detection. Also functions as a “locked rotor” input.
MAX31790 6-Channel PWM-Output Fan RPM Controller Block Diagram VCC XTAL1 XTAL2 I2C BUS TIMEOUT OSCILLATOR CIRCUIT INTERNAL OSCILLATOR GND POWER CONTROL FAN CONTROLLER LOGIC TACHn ENABLE PWMOUT6 OSC BIT DIVIDER CLKOUT PWMOUT5 WATCHDOG TIMER PWMOUT4 PULSE-WIDTH MODULATOR PWMOUT3 SCL PWMOUT2 SDA I2C INTERFACE BLOCK USER MEMORY PWMOUT1 TACH12 TACH11 TACH10 TACH9 TACH8 TACH7 ADD0 ADD1 SLAVE ADDRESS DECODE LOGIC TACH6 FAN TACHOMETER INPUTS TACH5 TACH4 TACH3 TACH2 TACH1 FAN FAIL LOGIC PO
MAX31790 6-Channel PWM-Output Fan RPM Controller Detailed Description The MAX31790 controls the speeds of up to six fans using six independent PWM outputs. The desired fan speeds (or PWM duty cycles) are written through the I2C interface. The outputs drive “4-wire” fans directly or can be used to control 2-wire or 3-wire fans by modulating the fan’s power supply voltage.
MAX31790 6-Channel PWM-Output Fan RPM Controller Configuration register. Spin-up can be disabled, or it can cause the fan to be driven with a 100% duty cycle until it produces two tachometer pulses, up to a maximum of 0.5s, 1s, or 2s. When spin-up is enabled and the duty cycle is making a transition from 0% to a value that is less than 100% (from 0% to 50%, for example), the duty cycle first goes to 100%.
MAX31790 6-Channel PWM-Output Fan RPM Controller Fan Monitoring Monitoring Tachometer Signals The TACH inputs accept either tachometer or “locked rotor” output signals from 3-wire or 4-wire fans. When measuring fan speed, the device counts the number of internal 8192Hz (fTOSC/4)clock cycles that occur during 1, 2, 4, 8, 16, or 32 tachometer periods. (The speed of each fan is measured once per second.) The number of tachometer periods is selectable for each fan by using the appropriate Fan Dynamics register.
MAX31790 6-Channel PWM-Output Fan RPM Controller TACH1 PWMOUT1 MAX31790 TACH1 PWMOUT1 MAX31790 TACH2 TACH2 PWMOUT2 (TACH8) PWMOUT2 (TACH8) TACH3 TACH3 PWMOUT3 (TACH9) PWMOUT3 (TACH9) TACH4 TACH4 PWMOUT4 PWMOUT4 (TACH10) TACH5 TACH5 PWMOUT5 (TACH11) PWMOUT5 (TACH11) TACH6 TACH6 PWMOUT6 (TACH12) PWMOUT6 (TACH12) Figure 3. 11 Fans, 11 TACH Monitors,1 PWM Maxim Integrated Figure 4.
MAX31790 6-Channel PWM-Output Fan RPM Controller TACH1 PWMOUT1 TACH1 PWMOUT1 MAX31790 MAX31790 TACH2 TACH2 PWMOUT2 (TACH8) PWMOUT2 (TACH8) TACH3 PWMOUT3 TACH3 PWMOUT3 TACH4 TACH4 PWMOUT4 PWMOUT4 (TACH10) TACH5 PWMOUT5 TACH5 PWMOUT5 (TACH11) TACH6 TACH6 PWMOUT6 PWMOUT6 (TACH12) Figure 5. 9 Fans, 9 TACH Monitors, 3 PWMs Figure 6. 8 Fans, 8 TACH Monitors, 4 PWMs Fan Failure When enabled, the device monitors the TACH inputs to determine when a fan has failed.
MAX31790 6-Channel PWM-Output Fan RPM Controller RPM Mode Failure Detection In RPM mode, a potential fault condition is identified when any of the following three conditions occur: 1) the TACH count exceeds the associated value stored in the TACH Target Count register while the PWM duty cycle is 100%, 2) the TACH count exceeds two times the TACH Target Count register value while the duty cycle is less than 100%, or 3) the TACH count reaches its maximum value of 7FFh.
MAX31790 6-Channel PWM-Output Fan RPM Controller Memory Description The device’s control registers are organized in rows of 8 bytes. The I2C master can read or write individual bytes, or can read or write multiple bytes. When writing consecutive bytes, all writes are to the same row. When the final byte in the row is reached, the next byte written is the row’s first byte. For example, a write that starts with 02h (Fan 1 Configuration) can write to 02h, 03h, 04h, 05h, 06h, and 07h.
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) R/W REGISTER POR STATE FUNCTION D7 D6 D5 D4 D3 R/W 05h 0XX0 0000b Fan 4 Configuration Same as Fan 1 Configuration R/W 06h 0XX0 0000b Fan 5 Configuration Same as Fan 1 Configuration R/W 07h 0XX0 0000b Fan 6 Configuration Same as Fan 1 Configuration Speed Range (TACH Periods Counted) 000b = 1 001b = 2 010b = 4 (default) 011b = 8 100b = 16 101b = 32 110b = 32 111b = 32 D2 PWM Rate-of-Change: 000b = 0ms per LSB (PW
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) R/W REGISTER POR STATE FUNCTION D7 D6 D5 Sequential Start Delay 000b = 0s 001b = 250ms 010b = 500ms 011b = 1s 100b = 2s 101b, 110b, 111b = 4s D4 D3 D2 Failed Fan Options 00b = duty cycle = 0% on fail 01b = Continue PWM or RPM mode operation on fail. 10b = duty cycle = 100% on fail 11b = All fans to 100% on any unmasked fan failure.
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) R/W REGISTER POR STATE FUNCTION D7 D6 D5 D4 D3 D2 D1 D0 R 26h 1111 1111b TACH 8 Count MSB R 27h 1110 0000b TACH 8 Count LSB R 28h 1111 1111b TACH 9 Count MSB R 29h 1110 0000b TACH 9 Count LSB R 2Ah 1111 1111b TACH 10 Count MSB R 2Bh 1110 0000b TACH 10 Count LSB R 2Ch 1111 1111b TACH 11 Count MSB R 2Dh 1110 0000b TACH 11 Count LSB R 2Eh 1111 1111b TACH 12 Count MSB R 2Fh 1110 0000b TACH
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) R/W REGISTER R 36h POR STATE FUNCTION 0000 0000b PWMOUT 4 Duty Cycle MSB R 37h 0000 0000b PWMOUT 4 Duty Cycle LSB R 38h 0000 0000b PWMOUT 5 Duty Cycle MSB R 39h 0000 0000b PWMOUT 5 Duty Cycle LSB R 3Ah 0000 0000b PWMOUT 6 Duty Cycle MSB D7 D6 D5 D4 D3 D2 D1 D0 Same as PWMOUT 1 Duty Cycle Same as PWMOUT 1 Duty Cycle Same as PWMOUT 1 Duty Cycle R 3Bh 0000 0000b PWMOUT 6 Duty Cycle LSB R 3Ch 0000 0
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) POR STATE R/W REGISTER FUNCTION D7 D6 D5 D4 D3 46h PWMOUT4 PWM_START Target Duty Cycle MSB R/W 47h PWMOUT4 PWM_START Target Duty Cycle LSB R/W 48h PWMOUT5 PWM_START Target Duty Cycle MSB R/W 49h PWMOUT5 PWM_START Target Duty Cycle LSB R/W 4Ah PWMOUT6 PWM_START Target Duty Cycle MSB R/W 4Bh PWMOUT6 PWM_START Target Duty Cycle LSB R/W 4Ch 0000 0000b User Byte — R/W 4Dh 0000 0000b User Byte — R/W 4Eh
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Map (continued) R/W REGISTER POR STATE FUNCTION D7 D6 D5 D4 D3 56h TACH 4 0011 1100b Target Count MSB R/W 57h TACH 4 0000 0000b Target Count LSB R/W 58h TACH 5 0011 1100b Target Count MSB R/W 59h TACH 5 0000 0000b Target Count LSB R/W 5Ah TACH 6 0011 1100b Target Count MSB R/W 5Bh TACH 6 0000 0000b Target Count LSB R/W 5Ch 0000 0000b User Byte — R/W 5Dh 0000 0000b User Byte — R/W 5Eh 0000 0000b User Byte — R/W
MAX31790 6-Channel PWM-Output Fan RPM Controller Register Descriptions X = Input state at POR. Global Configuration Register (00h) Power-On Value 0010 0XX0b Read Access All Write Access All Memory Type Volatile 00h Maxim Integrated Run/ Standby Reset Bus Timeout RESERVED OSC I2C Watchdog I 2C Watchdog Status BIT 7 BIT 0 BIT 7 Run/Standby: Places the device in standby mode. 0 = Run 1 = Standby Entering standby mode sets all PWM duty cycles to 0 and stops fan failure detection.
MAX31790 6-Channel PWM-Output Fan RPM Controller BITS 2:1 BIT 0 Maxim Integrated I2C Watchdog: When active, the watchdog monitors SDA and SCL for valid I2C transactions. If there are no valid transactions between the master and the device within the watchdog period, all fan PWM outputs go to 100%. If the watchdog times out and valid I2C transactions begin to occur again, operation resumes with the previous PWM value.
MAX31790 6-Channel PWM-Output Fan RPM Controller PWM Frequency Register (01h) Power-On Value XXXX XXXXb Read Access All Write Access All Memory Type Volatile 01h PWM4-PWM6 Frequency PWM1-PWM3 Frequency BIT 7 BIT 0 PWM4-PWM6 Frequency: These bits select the PWM OUT frequency for PWMOUT4, PWMOUT5, and PWMOUT6 according to the following: BITS 7:4 BITS 7:4 PWM OUPUT FREQUENCY POR CONDITION 0000b 25Hz — 0001b 30Hz FREQ_START = GND 0010b 35Hz — 0011b 100Hz — 0100b 125Hz — 0101b 14
MAX31790 6-Channel PWM-Output Fan RPM Controller Fan 1 Configuration Register (02h) Fan 2 Configuration Register (03h) Fan 3 Configuration Register (04h) Fan 4 Configuration Register (05h) Fan 5 Configuration Register (06h) Fan 6 Configuration Register (07h) Power-On Value 0XX0 0000b Read Access All Write Access All Memory Type Volatile 02h, 03h, 04h, 05h, 06h, 07h Mode Spin-Up Control/ Monitor TACH Input Enable TACH/ Locked Rotor Locked Rotor Polarity PWM/ TACH BIT 7 BIT 7 BIT 0 Mode: RPM
MAX31790 6-Channel PWM-Output Fan RPM Controller Maxim Integrated BIT 3 TACH Input Enable: Enables associated TACH input function and fan fault detection (automatically enabled in RPM mode). 0 = Disabled. When disabled and TACH input is not used, bits 1 and 2 are ignored. 1 = Enabled BIT 2 TACH/Locked Rotor: Selects TACH input function as TACH count or locked rotor. In locked rotor mode, assertion of the associated TACH input indicates that the fan has stopped.
MAX31790 6-Channel PWM-Output Fan RPM Controller Fan 1 Dynamics Register (08h) Fan 2 Dynamics Register (09h) Fan 3 Dynamics Register (0Ah) Fan 4 Dynamics Register (0Bh) Fan 5 Dynamics Register (0Ch) Fan 6 Dynamics Register (0Dh) Power-On Value 0100 1100b Read Access All Write Access All Memory Type Volatile 08h, 09h, 0Ah, 0Bh, 0Ch, 0Dh Speed Range Asymmetric Rate of Change PWM Rate-of-Change BIT 7 Reserved BIT 0 Speed Range: The device determines fan speed by counting the number of internal 81
MAX31790 6-Channel PWM-Output Fan RPM Controller BITS 4:2 PWM Rate-of-Change: PWM duty cycle rate of change. The PWM duty cycle at the associated PWMOUT outputs varies from 0 to full scale in 512 increments. The rate-of-change bits determine the time interval between duty cycle output increments/decrements. Regardless of the settings, there are a few cases for which the rateof-change is always 0: In RPM mode, when a TACH target count of 2047 (7FFh) is selected, the duty cycle immediately goes to 0%.
MAX31790 6-Channel PWM-Output Fan RPM Controller User Byte Register (0Eh–0Fh) User Byte Register (15h–17h) User Byte Register (4Ch–4Fh) User Byte Register (5Ch–5Fh) User Byte Register (66h–67h) Power-On Value 0000 0000b Read Access All Write Access All Memory Type Volatile 0Eh, 0Fh, 15h, 16h, 17h, 4Ch, 4Dh, 4Eh, 4Fh, 5Ch, 5Dh, 5Eh, 5Fh, 66h, 67h — — — — — — — BIT 7 — BIT 0 General-purpose volatile bits. These bits have no affect on the device operation.
MAX31790 6-Channel PWM-Output Fan RPM Controller Fan Fault Status 1 Register (11h) Power-On Value 0000 0000b Read Access All Write Access All Memory Type Volatile 11h RESERVED RESERVED Fan 6 Fault Fan 5 Fault Fan 4 Fault Fan 3 Fault Fan 2 Fault BIT 7 Fan 1 Fault BIT 0 BITS 7:6 RESERVED BITS 5:0 Fan [6:1] Fault: The associated fan experienced faults as defined in the Fan Failure section. When a fan fault is detected, the associated fault bit is set to 1.
MAX31790 6-Channel PWM-Output Fan RPM Controller Fan Fault Mask 1 Register (13h) Power-On Value 0011 1111b Read Access All Write Access All Memory Type Volatile 13h RESERVED RESERVED Fan 6 Mask BIT 7 Maxim Integrated Fan 5 Mask Fan 4 Mask Fan 3 Mask Fan 2 Mask Fan 1 Mask BIT0 BITS 7:6 RESERVED BITS 5:0 Fan [6:1] Mask: These bits mask faults on selected fans from asserting the FAN_FAIL output.
MAX31790 6-Channel PWM-Output Fan RPM Controller Failed Fan Options/Sequential Start Register (14h) Power-On Value 0100 0101b Read Access All Write Access All Memory Type Volatile 14h Sequential Start Delay RESERVED Failed Fan Options Fan Fault Queue BIT 7 BIT 0 Sequential Start Delay: Note that faults are not monitored until the channel is activated after its associated start delay.
MAX31790 6-Channel PWM-Output Fan RPM Controller TACH 1 Count Registers (18h–19h) TACH 2 Count Registers (1Ah–1Bh) TACH 3 Count Registers (1Ch–1Dh) TACH 4 Count Registers (1Eh–1Fh) TACH 5 Count Registers (20h–21h) TACH 6 Count Registers (22h–23h) TACH 7 Count Registers (24h–25h) TACH 8 Count Registers (26h–27h) TACH 9 Count Registers (28h–29h) TACH 10 Count Registers (2Ah–2Bh) TACH 11 Count Registers (2Ch–2Dh) TACH 12 Count Registers (2Eh–2Fh) Power-On Value 1111 1111b (MSB) 1110 0000b (LSB) Read Access
MAX31790 6-Channel PWM-Output Fan RPM Controller PWMOUT 1 Duty Cycle (30h–31h) PWMOUT 2 Duty Cycle (32h–33h) PWMOUT 3 Duty Cycle (34h–35h) PWMOUT 4 Duty Cycle (36h–37h) PWMOUT 5 Duty Cycle (38h–39h) PWMOUT 6 Duty Cycle (3Ah–3Bh) Power-On Value 0000 0000b (MSB) Read Access 0000 0000b (LSB) All Write Access N/A Memory Type Volatile 30h, 32h, 34h, 36h, 38h, 3Ah 28 27 26 25 24 23 22 21 31h, 33h, 35h, 37h, 39h, 3Bh 20 0 0 0 0 0 0 FS BIT 7 BIT 0 This is a 9-bit left-justified value tha
MAX31790 6-Channel PWM-Output Fan RPM Controller PWMOUT 1 Target Duty Cycle (40h–41h) PWMOUT 2 Target Duty Cycle (42h–43h) PWMOUT 3 Target Duty Cycle (44h–45h) PWMOUT 4 Target Duty Cycle (46h–47h) PWMOUT 5 Target Duty Cycle (48h–49h) PWMOUT 6 Target Duty Cycle (4Ah–4Bh) Power-On Value XXXX XXXXb (MSB) X000 0000b (LSB) All All Volatile Read Access Write Access Memory Type 40h, 42h, 44h, 46h, 48h, 4Ah 28 27 26 25 24 23 22 21 41h, 43h, 45h, 47h, 49h, 4Bh 20 RESERVED RESERVED RESERVED RESERVED
MAX31790 6-Channel PWM-Output Fan RPM Controller TACH 1 Target Count (50h–51h) TACH 2 Target Count (52h–53h) TACH 3 Target Count (54h–55h) TACH 4 Target Count (56h–57h) TACH 5 Target Count (58h–59h) TACH 6 Target Count (5Ah–5Bh) Power-On Value 0011 1100b (MSB) 0000 0000b (LSB) Read Access All Write Access All Memory Type Volatile 50h, 52h, 54h, 56h, 58h, 5Ah 210 29 28 27 26 25 24 23 51h, 53h, 55h, 57h, 59h, 5Bh 22 21 20 RESERVED RESERVED RESERVED RESERVED RESERVED BIT 7 BIT 0 Thi
MAX31790 6-Channel PWM-Output Fan RPM Controller Window 1 Register (60h) Window 2 Register (61h) Window 3 Register (62h) Window 4 Register (63h) Window 5 Register (64h) Window 6 Register (65h) Power-On Value 0000 0000b Read Access All Write Access All Memory Type Volatile 60h, 61h, 62h, 63h, 64h, 65h 27 BIT 7 26 25 24 23 22 21 20 BIT 0 When the fan’s speed is near the target speed in RPM mode—that is, when the TACH count is near the corresponding TACH target count—the control loop dynamics
MAX31790 6-Channel PWM-Output Fan RPM Controller I2C Serial Interface Description I2C Definitions The following terminology is commonly used to describe I2C data transfers. See the timing diagram (Figure 1) and the I2C AC Electrical Characteristics table for additional information. Master Device: The master device controls the slave devices on the bus. The master device generates SCL clock pulses and START and STOP conditions. Slave Devices: Slave devices send and receive data at the master’s request.
MAX31790 6-Channel PWM-Output Fan RPM Controller I2C Communication 2 See Figure 8 for I C communication examples. Manipulating the Address Counter for Reads: A dummy write cycle can be used to force the address counter to a particular value.
MAX31790 6-Channel PWM-Output Fan RPM Controller Applications Information Controlling 4-Wire Fans (PWM Mode) • Set bit 7 of the corresponding Fan Configuration register to 1. This selects RPM mode. The fan goes to the selected TACH target count. Initial Settings: Changing Speeds: • Begin with the POR settings. • Write the desired tachometer count to the corresponding TACH Target Count register.
MAX31790 6-Channel PWM-Output Fan RPM Controller VFAN 3.3V 3.3V 100kΩ 0.1µF 3.3V 4.7kΩ 100kΩ 2N3904 PWMOUT1 33kΩ 2.2µF 3.3V MAX31790 10µF 91kΩ 4.7kΩ TACH1 TACH OUTPUT TACH OUTPUT Figure 9. High-Side Linear Drive Circuit for 2-Wire or 3-Wire Fans L1 47µH R3 0.5Ω +20V VCC C3 47µF IPK D C R2 3.6kΩ C2 470µF IN 33063A C1 470pF D1 1N5819 E C4 0.1µF TC GND R1A 1.2kΩ 3.3V 0.1µF PWMOUT1 3.3V MAX31790 4.7kΩ TACH1 Figure 10.
MAX31790 6-Channel PWM-Output Fan RPM Controller A simpler approach to driving a 2-wire or 3-wire fan, although with important limitations, is to modulate the fan’s power supply with the PWM signal. In this case, a low PWM frequency (typically in the 30Hz range) is used to drive the gate of an n-channel MOSFET, which provides the connection between the fan and the power supply ground, as shown in Figure 11. There are three important disadvantages to this approach.
MAX31790 6-Channel PWM-Output Fan RPM Controller Revision History REVISION NUMBER REVISION DATE 0 12/12 Initial release — 1 4/13 Internal oscillator aging specification was required for Note 7 4 DESCRIPTION PAGES CHANGED Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied.
