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AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

EVALUATION KIT AVAILABLE

General Description

The MAX6966/MAX6967 serial-interfaced peripherals

provide microprocessors with 10 I/O ports rated to 7V.

Each port can be individually configured as either:

• A 20mA constant-current LED driver (static or pulse-

width modulated (PWM)).

• A 10mA constant-current LED driver (static or PWM).

• An open-drain logic output.

• An overvoltage-protected Schmitt logic input.

Analog and switching LED intensity control is built in:

• Individual 8-bit PWM control per output.

• Individual 1-bit analog control (half/full) per output.

• Global 3-bit analog control applies to all LED outputs.

PWM timing of the 10 port outputs may be optionally

staggered, consecutively phased in 45° increments.

This spreads the PWM load currents over time in eight

steps, helping to even out the power-supply current

and reduce the RMS current.

The MAX6966/MAX6967 can be configured to awake

from shutdown on receipt of a minimum 3ms pulse on

the CS input. This hardware-wakeup feature allows a

power-management controller or similar ASIC to enable

the MAX6966/MAX6967 with preconfigured LED intensi-

ty settings.

Shutdown can be programmed to wait up to 4s, fade

down the sink currents to zero for a period of 1/16s to

4s, and then shut down. A similar ramp-up from shut-

down can be programmed for 1/16s to 4s.

The MAX6966/MAX6967 support hot insertion. All port

pins remain high impedance in power-down (V+ = 0V)

with up to 8V asserted on them.

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.

Applications

LCD Backlights RGB LED Drivers

Keypad Backlights Portable Equipment

LED Status Indication Cellular Phones

Features

♦ High-Speed 26MHz SPI-™/QSPI-™/MICROWIRE™-

Compatible Serial Interface

♦ 2.25V to 3.6V Operation

♦ I/O Ports Default to High-Z (LEDs Off) on Power-Up

♦ I/O Port Inputs Are Overvoltage Protected to 7V

♦ I/O Port Outputs Are 7V-Rated Open Drain

♦ I/O Port Outputs Are 10mA or 20mA Constant-

Current Static/PWM LED Drivers, or Open-Drain

Logic Outputs

♦ I/O Ports Support Hot Insertion

♦ Individual 8-Bit PWM Intensity Control for Each LED

♦ Any Output May Use or Not Use PWM Control

♦ Exit Shutdown (Warm Start) with Simple CS Pulse

♦ Auto Ramp-Down into Shutdown

♦ Auto Ramp-Up Out from Shutdown

♦ 0.8µA (typ), 2µA (max) Shutdown Current

♦ Tiny 3mm x 3mm, 0.8mm High Thin QFN Package

♦ -40°C to +125°C Temperature Range

10-Port Constant-Current LED Drivers and I/O

Expanders with PWM Intensity Control

Ordering Information

19-3487; Rev 2; 4/05

PART

TEMP

RANGE

PIN-

PACKAGE

TOP

MARK

PKG

CODE

MAX6966ATE

-40°C to

+125°C

16 Thin QFN

3mm x 3mm x

0.8mm

ACF

T1633-4

MAX6966AEE

-40°C to

+125°C

16 QSOP — —

MAX6967ATE

-40°C to

+125°C

16 Thin QFN

3mm x 3mm x

0.8mm

ACG

T1633-4

MAX6967AEE

-40°C to

+125°C

16 QSOP — —

SPI and QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

MAX6966/MAX6967

Ordering Information

Summary of content (29 pages)

PAGE 1
EVALUATION KIT AVAILABLE LE AVAILAB MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control General Description Features The MAX6966/MAX6967 serial-interfaced peripherals provide microprocessors with 10 I/O ports rated to 7V. ♦ High-Speed 26MHz SPI-™/QSPI-™/MICROWIRE™Compatible Serial Interface Each port can be individually configured as either: • A 20mA constant-current LED driver (static or pulsewidth modulated (PWM)).
PAGE 2
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control ABSOLUTE MAXIMUM RATINGS Voltage (with respect to GND) V+ .............................................................................-0.3V to +4V SCLK, DIN, CS, DOUT/OSC.........................-0.3V to (V+ + 0.3V) P_ .............................................................................-0.3V to +8V DC Current into P_ .............................................................
PAGE 3
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control ELECTRICAL CHARACTERISTICS (continued) (Typical Operating Circuit, V+ = 2.25V to 3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at V+ = 3.3V, TA = +25°C.
PAGE 4
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control TIMING CHARACTERISTICS (Typical Operating Circuit, V+ = 2.25V to 3.6V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at V+ = 3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL Internal PWM Clock Frequency fINT External PWM Clock Frequency fOSC CONDITIONS MIN 27000 TYP MAX UNITS 45000 Hz 100 kHz SCLK Clock Period tCP 38.
PAGE 5
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) SUPPLY CURRENT (I+) vs. TEMPERATURE V+ = 3.3V 0.9 V+ = 2.7V 0.8 0.7 0.6 0.3 V+ = 2.7V 0.2 V+ = 2.25V 0.1 0.5 10 8 6 4 2 V+ = 2.25V 0.4 0 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) TEMPERATURE (°C) 0 2 3 4 5 INTERNAL OSCILLATOR FREQUENCY vs.
PAGE 6
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Pin Description PIN NAME FUNCTION QSOP TQFN 1 15 SCLK 2 16 CS Chip-Select Input. Serial data is loaded into the shift register while CS is low. The most recent 16 bits of data latch on CS’s rising edge. 3–7, 9-13 1–5, 7-11 P0-P9 I/O Ports. P0 to P9 can be configured as open-drain current-sink outputs rated at 20mA maximum, or as CMOS-logic inputs, or as open-drain logic outputs.
PAGE 7
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control The tradeoff for LED intensity control is between depth of current-control resolution, noise constraints, and software complexity: • For high LED resolution where each LED needs individual intensity settings, use the 8-bit PWM control plus the 1-bit analog control to get 9 bits of individual LED intensity control.
PAGE 8
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control I/O PORT A POSITION A: 0x00 - 0x01 B ENABLE = 0x00 POSITION B: 0x02 - 0xFF CLOSE SWITCH: 0x02-0xFE 8-BIT LATCH OUTPUT PORT REGISTER PWM GENERATOR ENABLE TO/FROM SERIAL INTERFACE 1-BIT LATCH OUTPUT CURRENT REGISTER SET CURRENT MSB N 4-BIT DAC 3-BIT LATCH GLOBAL CURRENT REGISTER READ I/O PORT COMMAND Figure 1.
PAGE 9
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control If a port is changed from static logic low (0x00) or static logic high (0x01) to a constant-current value (0x02–0xFE) in shutdown mode, then that output is automatically turned off (logic high, or high impedance) like any other constant-current outputs that are disabled in shutdown. When shutdown mode is exited, the new constant-current output starts just like any other constant-current outputs.
PAGE 10
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Register Structure The MAX6966/MAX6967 contain 16 internal registers, addressed as 0x00–0x09, and 0x10–0x15, which configure and control the peripheral (Table 2). Two addresses, 0x0E and 0x0F, do not store data but return the port input status when read. Four virtual addresses, 0x0A–0x0D allow more than one register to be written with the same data to simplify software.
PAGE 11
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Initial Power-Up On power-up, all control registers are reset (Table 3). Power-up status sets I/O ports P0 to P9 high impedance, 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 lowest power condition. PWM Clock lator and PWM logic are disabled automatically, and the MAX6966/MAX6967 operating current is lowest.
PAGE 12
MAX6966/MAX6967 10-Port 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 individually to a PWM duty between 3/256 and 254/256. PWM timing can be configured one of two ways by the setting of the stagger bit in the configuration register (Table 4). When the stagger bit is clear, all outputs using PWM switch at the same time use the timing shown in Figure 2.
PAGE 13
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 4.
PAGE 14
MAX6966/MAX6967 10-Port 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 phasing between outputs, test fade status, enable hardware startup from shutdown, and select shutdown or run mode (Table 4).
PAGE 15
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 6.
PAGE 16
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 6.
PAGE 17
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Output Current Registers Each output port’s individual constant-current sink can be set to be either half or full global current. The individual currents are set by the output current registers (Table 7). The global current is set by the global current register (Table 8).
PAGE 18
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 8. Global Current Register Format REGISTER R/W ADDRESS CODE (HEX) REGISTER DATA D7 D6 D5 D4 D3 0 X X X X X ISET2 ISET1 ISET0 1 0 0 0 0 0 ISET2 ISET1 ISET0 Full current is 2.5mA; half current is 1.25mA X X X X X X 0 0 0 Full current is 5mA; half current is 2.5mA X X X X X X 0 0 1 Full current is 7.5mA; half current is 3.
PAGE 19
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control The ramp-down register sets the hold-off and fade-off times and allows hold-off and fade-off to be disabled (zero delay), if desired (Table 9). The ramp-up register sets the ramp-up time and allows ramp-up to be disabled (zero delay), if desired (Table 10). The configuration register contains 3 status bits that identify whether the MAX6966/MAX6967 are in hold-off, fade-off, or rampup condition (Table 4).
PAGE 20
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Table 10.
PAGE 21
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Control and Operation Using the 4-Wire Interface Serial Interface The MAX6966/MAX6967 communicate through an SPIcompatible 4-wire serial interface. The interface has three inputs: clock (SCLK), chip select (CS), and data in (DIN), and one output, data out (DOUT). CS must be low to clock data into or out of the device, and DIN must be stable when sampled on the rising edge of SCLK.
PAGE 22
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Alternatively, the MAX6966/MAX6967s can be daisychained by connecting the DOUT of one device to the DIN of the next, and driving SCLK and CS lines in parallel (Figure 9). This connection allows the MAX6966/ MAX6967s to be read. Data at DIN propagates through the internal shift registers and appears at DOUT 15.5 clock cycles later, clocked out on the falling edge of SCLK.
PAGE 23
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control The MAX6966/MAX6967 are written to using the following sequence (Figure 11): 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, observing the setup and hold times. Bit D15 is low, indicating a write command. 4) Take CS high (either while SCLK is still high after clocking in the last data bit, or after taking SCLK low).
PAGE 24
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Applications Information Hot Insertion The I/O ports P0–P9 remain high impedance with up to 8V asserted on them when the MAX6966/MAX6967 are powered down (V+ = 0V). The MAX6966/MAX6967 can therefore be used in hot-swap applications. SPI Routing Considerations The MAX6966/MAX6967s’ SPI interface is guaranteed to operate at 26Mbps on a 2.5V supply, and on a 3.3V supply typically operate at 35Mbps.
PAGE 25
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Figure 13 shows the typical current sunk by a LITEON LTST-C170TBKT 3.0V blue LED as the LED supply voltage is varied from 2.5V to 7V. The LED currents shown are for ports programmed for 10mA and 20mA constant current, swept over a 2.5V to 7V LED supply voltage range. It can be seen that the LED forward voltage falls with current, allowing the LED current to fall gracefully, not abruptly, in brownout.
PAGE 26
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control In run mode, the output port goes low, approaching 0V, as the port’s static constant current saturates trying to sink a higher current than the 220kΩ pullup resistor can source. In shutdown mode, the output goes high impedance together with any other constant-current outputs.
PAGE 27
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Block Diagram CURRENT REFERENCE INTERNAL OSCILLATOR RAMP-UP/RAMP-DOWN CONTROLS P0 P1 P2 PWM CONTROLLER I/O PORTS P3 P4 P5 P6 OSC P7 P8 P9 EXTERNAL CLOCK INPUT CONFIGURATION REGISTER CLK CS DIN DOUT I/O REGISTER 4-WIRE SERIAL INTERFACE Chip Information TRANSISTOR COUNT: 14,865 PROCESS: BiCMOS Maxim Integrated 27
PAGE 28
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Package Information QSOP.EPS (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PACKAGE OUTLINE, QSOP .150", .
PAGE 29
MAX6966/MAX6967 10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control Package Information (continued) (NE - 1) X e E MARKING 12x16L QFN THIN.EPS (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) E/2 D2/2 (ND - 1) X e AAAA D/2 e CL D D2 k CL b 0.10 M C A B E2/2 L E2 0.10 C C L 0.