Product category: Power Supply ICs and Controllers
News Release from: Maxim Integrated Products | Subject: MAX6970/71/80/81/83
Edited by the Electronicstalk Editorial Team on 28 October 2005
LED drivers keep lights and signs
constant
Five new constant-current LED drivers are designed to support standard lighting and signage applications.
New from Maxim Integrated Products are the MAX6971/MAX6983 16-port and the MAX6970/MAX6980/MAX6981 eight-port constant-current LED drivers All these LED drivers feature a 25MHz, four-wire, industry-standard SPI-compatible serial interface
This article was originally published on Electronicstalk on 27 Aug 2002 at 8.00am (UK)
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The 16 or eight open-drain, constant-current-sinking LED driver outputs are rated at 36V.
Using a single external resistor with a 2% current matching between outputs and 6% matching between cascaded devices, each port can sink up to 55mA for all LEDs.
They operate from a 3 to 5.5V supply and are specified for the -40 to +125C operating range.
All the devices are designed to support standard lighting and signage applications.
The MAX6971/MAX6983 16-port drivers use the industry-standard, shift-register-plus-latch-type serial interface.
The driver accepts data shifted into a 16bit shift register using data input and clock input pins.
Input data appears at the data output 16 clock cycles later to allow cascading of multiple devices.
The latch-enable input loads the 16bit shift register data into a 16bit output latch to determine which LEDs are on and which are off.
The output enable gates all 16 outputs on and off, and is fast enough to be used as a PWM input for LED intensity control.
Some lighting or signage applications require LED fault detection and fail-safe protection, which the 16-port MAX6983 and eight-port MAX6980 are unique to provide.
A LED fault-detect feature reports open-circuit LED faults in the data stream.
A watchdog timer clears the screen if the serial interface fails for more than 1s.
The fault detection and watchdog alleviate the need for tedious, external protective circuitry, which saves design time and lowers the cost of traffic and marquee signs, gaming and architectural lighting applications.
Among the eight-port LED drivers, the MAX6970 provides standard, register-latched LED driver functionality.
MAX6981 adds LED open-circuit fault-detection.
The 16-port MAX6971/MAX6983 are available in 24-pin TSSOP and 24-pin narrow PDIP packages, and the eight-port MAX6970/MAX6980/MAX6981 are available in 16-pin TSSOP and PDIP packages.
The price for the MAX6971 and MAX6083 16-port devices is $1.98 and $2.14, respectively.
The MAX6970 is priced at $0.99, the MAX6981 at $1.03, and the MAX6980 at $1.11.
All driver prices are 1000-up, FOB USA.
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