MAX6966 Maxim, MAX6966 Datasheet
MAX6966
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MAX6966 Summary of contents
Page 1
... The DOUT/OSC pin can be configured as either the serial interface data output or optional PWM clock input. The MAX6966 powers up defaulting as DOUT output. The MAX6967 defaults as OSC input. For a similar part without the constant-current controls, refer to the MAX7317 data sheet. ...
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... Total GND Current ............................................................280mA Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control ELECTRICAL CHARACTERISTICS (continued) (Typical Operating Circuit 2.25V to 3.6V, T +25°C.) (Note 1) PARAMETER SYMBOL Input High Voltage (P0–P9, DIN, SCLK, CS, OSC) Input Low Voltage (P0–P9, ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control TIMING CHARACTERISTICS (Typical Operating Circuit 2.25V to 3.6V, T +25°C.) (Note 1) PARAMETER SYMBOL Internal PWM Clock Frequency External PWM Clock Frequency f SCLK Clock Period SCLK ...
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... LED 110 125 EXT LED INTERNAL OSCILLATOR FREQUENCY vs. TEMPERATURE 2.25V -40 -25 - 110 125 TEMPERATURE (°C) STAGGER PWM PORT WAVEFORMS (OUTPUT REGISTERS SET TO 0x80) MAX6966/67 toc07 2ms AT 10mA (V) 5 ...
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... DOUT/OSC OSC Input. Apply a square-wave CMOS clock up to 100kHz as alternate PWM clock source. The MAX6966 powers up with DOUT/OSC defaulting as DOUT output. The MAX6967 powers up with DOUT/OSC defaulting as OSC input. Serial-Data Input. Data from DIN loads into the internal 16-bit shift register on SCLK’s rising ...
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... Take care with PC board layout. The MAX6966/ MAX6967 are switching moderate currents in PWM applications, so the MAX6966/MAX6967 and the load supplies need careful decoupling to minimize conducted noise ...
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... LATCH GLOBAL CURRENT REGISTER Figure 1. Simplified Schematic of I/O Ports Figure 1 shows the I/O port structure of the MAX6966/ MAX6967. I/O ports default to high impedance on power-up, so LED or other port loads connected draw no current, and ports used as inputs do not load their source signals. Standby Mode and Operating Current ...
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... GPIO output. When shut- down mode is exited, the new GPIO output is unaffect- ed just like any other GPIO outputs. The MAX6966/MAX6967 can be configured so that a relatively long pulse on the CS input brings the driver out of shutdown alternative method to the normal method of writing the configuration register through the serial interface ...
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... The no-op address, 0x20, causes no action when written or read, and is used as a dummy register when accessing one (Table 2). Two MAX6966/MAX6967 out of multiple cascaded devices. COMMAND ADDRESS D15 D14 D13 D12 ...
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... Power-up status sets I/O ports high imped- ance, and puts the device into shutdown mode. This means that any LED (or other) loads are effectively turned off, and the MAX6966/MAX6967 start in its low- est power condition. An internal 32kHz oscillator generates PWM timing. If all output ports are set to static levels, the internal oscil- Table 3 ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control PWM Timing and Phasing A PWM period comprises 256 cycles of the nominal 32kHz PWM clock (Figure 2). Ports can be set individu- ally to a PWM duty between ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 4. Configuration Register REGISTER CONFIGURATION Write device configuration Read-back device configuration Shutdown mode (CS run disabled) Put or keep device in shutdown, disable CS run Shutdown mode (CS ...
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... Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control The stagger bit is ideally set or cleared when the MAX6966/MAX6967 are in shutdown. If not, there may be a perceived transient flicker in any PWM-controlled LEDs because the fundamental PWM timing is being changed. Configuration Register The configuration register is used to select PWM phas- ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 6. Output Registers Format REGISTER PORT P0 LEVEL OR PWM Port P0 is static-low logic-level logic port with logic input buffer enabled; reading this port returns 0. Still ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 6. Output Registers Format (continued) REGISTER Port P1 level or PWM Port P2 level or PWM Port P3 level or PWM Port P4 level or PWM Port P5 ...
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... Output P9 is set to full constant current ______________________________________________________________________________________ Each output current can be set individually to best suit the maximum operating current of an LED load, or even adjusted on the fly to double the effective intensity con- trol range of each output. When the global current reg- ister is set to maximum, the individual current selection is 10mA (half) or 20mA (full) ...
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... By default, maximum current is 20mA, so the default half current is 10mA. Ramp-Up and Ramp-Down Controls The MAX6966/MAX6967 provide automatic controls that allow the currents’ outputs to be ramped down into automatic shutdown (ramp-down), and ramped up again out of shutdown (ramp-up) without further inter- ...
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... MAX6966/MAX6967 are in hold-off, fade-off, or ramp- up condition (Table 4). The configuration register also enables or disables ramp-up. One write to the configura- tion register can put the MAX6966/MAX6967 into shut- down (using hold-off and fade-off settings in the fade Table 9. Ramp-Down Register Format REGISTER Write ramp-down ...
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... This means that LEDs are always faded at the same rate even if their different intensity settings are totally different. The maximum port output current set by the global cur- rent register down that the current starts falling, and the point during ramp-up that the current stops rising. ...
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... Multiple MAX6966/MAX6967s can be interfaced to a common SPI bus by connecting DIN inputs together, connecting SCLK inputs together, and providing an individual CS per MAX6966/MAX6967 device 8). This connection works regardless of the configura- tion of DOUT/OSC, but does not allow the MAX6966/ MAX6967s to be read. D10 D9 D8 ...
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... DOUT 15.5 clock cycles later, clocked out on the falling edge of SCLK. When sending commands to daisy-chained MAX6966/MAX6967s, all devices are accessed at the same time. An access requires ( clock cycles, where n is the number of MAX6966/MAX6967s connect- MOSI CS SCLK µC ...
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... N- DOUT N-31 N-30 Figure 12. Transmission of More than 16 Bits to the MAX6966/MAX6967 ______________________________________________________________________________________ Any register data within the MAX6966/MAX6967 can be read by sending a logic high to bit D15. The sequence is: 1) Take SCLK low. 2) Take CS low. This enables the internal 16-bit shift register. 3) Clock 16 bits of data into DIN, D15 first to D0 last. ...
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... This limits the loading on the PWM clock source on power-up when a MAX6966 is fitted, because DOUT/OSC initializes as an output. If DOUT/OSC is used as DOUT, remember that a MAX6967 cannot be read after power-up until DOUT/OSC has been reconfigured from OSC to DOUT ...
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... An I/O port can be used to automatically generate a shutdown/run output from the MAX6966/MAX6967. The shutdown/run output is active low when the MAX6966/MAX6967 are in run mode, hold-off, fade-off, or ramp-up, and go high automatically when the MAX6966/MAX6967 finally enter shutdown after fade- off. Program the port’s output register to value 0x00, ...
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... Driving Load Currents Higher than 20mA The MAX6966/MAX6967 can be used to drive loads needing more than 20mA, like high-current white LEDs, by paralleling outputs. For example, consider a white LED that needs to be driven with 70mA. This LED can µ ...
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Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control CURRENT REFERENCE INTERNAL OSCILLATOR EXTERNAL CLOCK INPUT OSC CONFIGURATION CLK CS DIN DOUT ______________________________________________________________________________________ RAMP-UP/RAMP-DOWN CONTROLS PWM CONTROLLER REGISTER I/O REGISTER 4-WIRE SERIAL INTERFACE TRANSISTOR COUNT: 14,865 PROCESS: BiCMOS ...
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... Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) 28 ______________________________________________________________________________________ Package Information PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH ...
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... NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY. 12. WARPAGE NOT TO EXCEED 0.10mm. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. ...