MAX6946 Maxim, MAX6946 Datasheet
MAX6946
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MAX6946 Summary of contents
Page 1
... I/O Ports Support Hot Insertion ♦ Individual 8-Bit PWM Intensity Control for Each LED ♦ RST Input Clears Serial Interface and Can Exit Shutdown (Warm Start) ♦ MAX6946 OSC Input Allows for External PWM Clock Input ♦ MAX6947 AD0 Input Selects from Two Slave Addresses ♦ ...
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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 Driver and I/O Expander with PWM Intensity Control ELECTRICAL CHARACTERISTICS (continued 2.25V to 3.6V MIN MAX PARAMETER Input High Voltage (P0–P9, SDA, SCL, RST, AD0, OSC) Input Low ...
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... RST Pulse Width RST Rising Edge to MAX6946/MAX6947 ACK to Cancel Reset Run RST Rising Edge to MAX6946/MAX6947 ACK to Ensure Reset Run Note 1: All parameters are tested Note 2: Port current is factory trimmed to meet a median sink current of 20mA and 10mA over all ports. The ΔI guarantees current matching between parts ...
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... DD 0 -40 -25 - 110 125 TEMPERATURE (°C) OUTPUT SINKING CURRENT ) DD20 vs EXT LED (V) EXT LED MAX6946/47 toc08 PORT P0 2V/div PORT P4 2V/div PORT P7 2V/div 1ms/div ) RST 2.25V DD AT 10mA ...
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... CURRENT REFERENCE EXTERNAL CLOCK INPUT* OSC* MAX6946 MAX6947 ADO** SCL SDA RST **MAX6946 ONLY. **MAX6947 ONLY. 6 _______________________________________________________________________________________ NAME P0 P1 I/O Ports. Configure P0–P4 as open-drain current sink outputs rated at P2 20mA (max), as CMOS-logic inputs open-drain logic outputs. Connect loads to a supply voltage no higher than 7V. ...
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... PWM timing of the 10 port outputs in con- secutively phased 45° increments. The I/O ports also feature ramp-up and ramp-down controls. The MAX6946/MAX6947 feature a RST input to halt any serial-interface transmission and bring the device out of shutdown. Open-drain logic outputs require external pullup resis- tors to provide the logic-high reference ...
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... Ramp-up status** RST RUN enable D1 D0 RUN enable *The OSCEN bit applies only to the MAX6946. OSCEN is always 0 for the MAX6947, and the MAX6947 ignores writes to the OSCEN bit. **Read-only bits. Table 3. Initial Power-Up Register Status DESCRIPTION POWER-UP CONDITION Port P0–P9 output level Port 0– ...
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... I/O Ports Phasing section). The I/O ports are high impedance without V power-up. Figure 1 shows the I/O port structure of the MAX6946/ MAX6947. I/O ports default to high impedance on power-up, so LEDs or other port loads connected draw no current. Ports used as inputs do not load their source signals. POSITION A: 0x00–0x01 POSITION B: 0x02– ...
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... Set the global current by the global- current register (Table 5). Set each output current individually to best suit the maximum operating current of an LED load, or even adjust on the fly to double the effective intensity control range of each output. The individual current selection is 10mA (half) or 20mA (full) when setting the global-cur- rent register to its maximum value ...
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... PWM Intensity Control and Phasing The MAX6946/MAX6947 use an internal 32kHz oscilla- tor to generate PWM timing for LED intensity control. The MAX6946 also features an OSC input to allow for an external clock for generating PWM timing for LED intensity control. Select the PWM clock source for the MAX6946 with configuration register bit D7 (Table 2) ...
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... The input port regis- ter returns logic 0 in the appropriate bit position for a port not configured as a logic input. The input port’s registers are read only. The MAX6946/ MAX6947 ignore a write to input ports register. The active-low RST input operates as a reset that voids ...
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... Use the MAX6946/ MAX6947 for a mix of logic inputs, logic outputs, and PWM LED drivers, and only the LED drivers turn off automatically in shutdown ...
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... One write command to the configuration register can put the MAX6946/MAX6947 into shutdown (using hold-off and fade-off settings in the fade register) and one read command to the configuration register can determine whether the Reset Run is enabled for restart, and whether the MAX6946/MAX6947 will use ramp-up on restart. 3/8 2/8 1/8 ...
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... If RST pulses high for less than this timeout period to trigger a Reset Run, the MAX6946/ MAX6947 ignore the pulse, and the MAX6946/MAX6947 continue to wait for a suitable trigger. ...
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... SCL output. Each transmission consists of a START condition (Figure 9) sent by a master, followed by the MAX6946/ MAX6947 7-bit slave address plus the R/W bit, a regis- ter address byte, one or more data bytes, and finally a STOP condition (Figure 9) ...
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... The pointer autoincrements after each data byte is read using the same rules as for a write (Table 1). Thus, a read is initiated by first configuring the MAX6946/ MAX6947s’ command byte by performing a write (Figures 12 and 13). The master can now read n con- ...
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... A COMMAND BYTE The MAX6946/MAX6947s’ slave address select input AD0 (MAX6947 only), PWM clock input OSC (MAX6946 only), and reset input RST are overvoltage protected to +6V, independent The 10 I/O ports P0–P9 are overvoltage protected DD to +8V independent of V MAX6947 to operate from one supply voltage, such as 3 ...
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... MAX6946/MAX6947 power down. Use the MAX6946/MAX6947 in hot-swap applications. Differences Between the MAX6946 and MAX6947 The MAX6946 features the OSC input, allowing the device to use an external clock as the PWM clock source. The MAX6946 features a fixed I address of 0100000. The MAX6947 features an AD0 ...
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... This optimally spreads out the current demand from the ports’ load supply. Generating a Shutdown/Run Output The MAX6946/MAX6947 can use an I/O port to auto- matically generate a shutdown/run output. The shut- down/run output is active low when the MAX6946/ MAX6947 are in run mode, hold-off, fade-off, or ramp- up, and goes high automatically when the devices final- ly enter shutdown after fade-off. Programming the port’ ...
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... Constant-Current LED Driver and I/O Expander 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.) E MARKING E/2 AAAA D 0. ______________________________________________________________________________________ ( ...
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... Constant-Current LED Driver and I/O Expander 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.) PKG 8L 3x3 12L 3x3 REF. MIN. NOM. MAX. MIN. ...
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... Constant-Current LED Driver and I/O Expander 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.) ______________________________________________________________________________________ Package Information (continued) 23 ...
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... Added MAX6946C (WLP package) to the data sheet. 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. ...