MAXIM MAX6946, MAX6947 User Manual

General Description

The MAX6946/MAX6947 I2C-/SMBusTM-compatible, serial-interfaced peripherals provide microprocessors with 10 I/O ports rated to 7V.

Each port can be configured as a 2.5mA to 20mA constant-current LED driver (static or PWM), a 1.25mA to 10mA constant-current LED driver (static or PWM), an open-drain logic output, or an overvoltage-protected Schmitt logic input.

Analog and switching LED intensity control includes individual 8-bit PWM control per output, individual 1-bit analog current control (half/full scale) per output, and a global 3-bit DAC current control that applies to all LED outputs.

The MAX6946/MAX6947 can stagger the PWM timing of the 10-port outputs in consecutively phased 45° increments. Staggering the outputs spreads the PWM load currents over time in eight steps, helping to even out the power-supply current and reduce the RMS current.

For a similar part with an SPITM-/QSPITM-/ or MICROWIRETMcompatible interface, refer to the MAX6966/MAX6967 data sheet.

Applications

Features

♦ 2.25V to 3.6V Operation ♦ I/O Ports Default to High Impedance (LEDs Off)

on Power-Up

♦ I/O Port Inputs Are Overvoltage Protected to 7V ♦ I/O Port Outputs Are 7V-Rated Open-Drain, 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 ♦ 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

♦ Auto Ramp-Up Out of Shutdown, and Up to 4s

Hold-Off Before Ramp-Down into Shutdown

♦ 0.8µA (typ) Shutdown Current ♦ -40°C to +125°C Temperature Range ♦ Tiny WLP Package (4 x 4 Grid)

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and

I/O Expander with PWM Intensity Control

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

MAX6946 MAX6947

+3.3V

μC

SDA

EXT

= +5V

P0 P1 P2 P3 P4 P5 P6 P7

SCL

SDA

SCL

GND

OSC*

P8 P9

LOGIC INPUT

RST

AD0**

*MAX6946 ONLY. **MAX6947 ONLY.

Typical Operating Circuit

19-0598; Rev 3; 2/08

+Denotes a lead-free package. *EP = Exposed pad.

Note: All devices are specified over the -40°C to +125°C operating temperature range..

EVALUATION KIT

AVAILABLE

PART PIN-PACKAGE

PKG

CODE

MAX6946ATE+ 16 TQFN-EP* T1633-4

MAX6946CAWE+ 16 WLP W162B2-1

MAX6947ATE+ 16 TQFN-EP* T1633-4

SMBus is a trademark of Intel Corp.

SPI and QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

Cellular Phones Portable Equipment RGB LED Drivers

LCD Backlights Keypad Backlights LED Status Indicators

(BUMPS ON BOTTOM)

16-BUMP, 2.1mm x 2.1mm WLP

VDD

SDA

RST

SCL

OSC

GND

TOP VIEW

A1 A2 A3 A4

B4B3B2B1

C1 C2 C3 C4

D1 D2 D3 D4

MAX6946C

Pin Configurations

Pin Configurations continued at end of data sheet.

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and I/O Expander with PWM Intensity Control

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= 2.25V to 3.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VDD= 3.3V, TA= +25°C.) (Note 1)

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.

VDD to GND .............................................................-0.3V to +4V

SCL, SDA, AD0,

RST, OSC to GND .........................-0.3V to +6V

P0 to P9 to GND .......................................................-0.3V to +8V

DC Current into P0 to P9 ....................................................24mA

DC Current into SDA ...........................................................10mA

RST Sink Current.................................................................10mA

Total GND Current ............................................................280mA

Continuous Power Dissipation (T

= +70°C)

16-Pin TQFN (derate 14.7mW/°C over +70°C) ..........1176mW

16-Bump WLP (derate 13.3mW/°C over +70°C)........1066mW

Operating Temperature Range (T

MIN

, T

MAX

)....-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

CONDITIONS

UNITS

Operating Supply Voltage V

Output Load External Supply Voltage P0–P9

EXT

Power-On-Reset Voltage V

POR

VDD rising

16-pin TQFN

Power-On-Reset Voltage Hysteresis

16-bump WLP 33

TA = +25°C

Standby Current Interface Idle (PWM Disabled, All Ports High Impedance)

STBY

RST at VDD; f

SCL

= 0Hz; other digital

inputs at VDD or GND

= T

MIN

to T

MAX

µA

TA = +25°C 17 23

Standby Current in Reset (PWM Disabled, All Ports High Impedance)

RST

RST at GND; f

SCL

= 400kHz; other digital inputs at VDD or GND

= T

MIN

to T

MAX

µA

TA = +25°C 50 60

Supply Current Interface Active (Reset Run Enabled, PWM Disabled, All Ports High Impedance)

SCL

= 400kHz; other digital inputs at VDD or GND

= T

MIN

to T

MAX

µA

TA = +25°C

One port set to 10mA constant current; all other ports' output registers set to 0x00, 0x01, or 0xFF; digital inputs at VDD or GND

= T

MIN

to T

MAX

TA = +25°C

Delta Supply Current Interface Idle

One port set to 20mA constant current; all other ports' output registers set to 0x00, 0x01, or 0xFF; digital inputs at VDD or GND

= T

MIN

to T

MAX

SYMBOL

MIN TYP MAX

2.25 3.60

1.91

PORHYS

128

TA = T

to +85°C 1.3

MIN

to +85°C

MIN

ΔI

DD10

TA = T

to +85°C

MIN

to +85°C 1.9

MIN

ΔI

DD20

TA = T

to +85°C 3.8

MIN

1.0 1.3

1.5

1.58 1.8

2.0

3.2 3.6

4.0

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and

I/O Expander with PWM Intensity Control

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= 2.25V to 3.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VDD= 3.3V, TA= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

Input High Voltage

(P0–P9, SDA, SCL, RST, AD0, OSC)

P0–P9: output register set to 0x01

0.7 V

Input Low Voltage

(P0–P9, SDA, SCL, RST, AD0, OSC)

P0–P9: output register set to 0x01

0.3 V

Input Leakage Current

(P0–P9, SDA, SCL, RST, AD0, OSC)

µA

Input Capacitance

(P0–P9, SDA, SCL, RST, AD0, OSC)

10 pF

TA = +25°C

16-pin TQFN

10mA Port Nominal Sink Constant Current (P0–P9)

OUT

Outp ut r eg i ster set to 0x02, V

D D

= 3.3V ,

16-bump WLP

TA = +25°C

16-pin TQFN

20mA Port Nominal Sink Constant Current (P0–P9)

OUT

Outp ut r eg i ster set to 0x02, V

D D

= 3.3V ,

16-bump WLP

TA = +25°C, VDD = 3.3V, VP0 to VP9 = 1.4V, I

OUT

= 20mA

Port Sink Constant-Current Matching

TA = +25°C, VDD = 3.3V, VP0 to VP9 = 1.4V, I

OUT

= 10mA

Port Logic Output Low Voltage (P0–P9)

Output register set to 0x00, I

SINK

= 0.5mA

Port Logic Output Low Short-Circuit Current (P0–P9)

Output register set to 0x00, V

OLP_

= 5V

Port Slew Time From 20% current to 80% current 2 µs

Output Low Voltage (SDA)

SINK

= 6mA

SYMBOL

IIH, I

E X T

ΔI

OUT

OLP_

- V

LE D

= 1V ( N ote 3)

TA = T

= T

TA = T

= T

to +85°C

MIN

to +85°C

MIN

to +85°C

MIN

to +85°C

MIN

MIN TYP MAX

x V

-0.2 +0.2

9.3

9.1 11.0

9.0 11.0

19.00

18.6 21.8

18.4 22.0

±2.0 ±4.0

±2.0 ±5.0

x V

10.5

21.12

0.5

OLSDA

300

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and I/O Expander with PWM Intensity Control

4 _______________________________________________________________________________________

TIMING CHARACTERISTICS (Figure 8)

(VDD= 2.25V to 3.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VDD= 3.3V, TA= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

16-pin TQFN 23 32 42

Internal PWM Clock Frequency f

INT

16-bump WLP 20 32 45

kHz

External PWM Clock Frequency f

OSC

100

kHz

Serial-Clock Frequency f

SCL

400

kHz

Bus Free Time Between a STOP and a START Condition

BUF

1.3 µs

Hold Time, (Repeated) START Condition

0.6 µs

Repeated START Condition Setup Time

0.6 µs

STOP Condition Setup Time

0.6 µs

Data Hold Time

(Note 3) 0.9 µs

Data Setup Time

180 ns

SCL Clock Low Period t

LOW

1.3 µs

SCL Clock High Period t

HIGH

0.7 µs

Rise Time of Both SDA and SCL Signals, Receiving

(Notes 4, 5)

300 ns

Fall Time of Both SDA and SCL Signals, Receiving

(Notes 4, 5)

300 ns

Fall Time of SDA Transmitting t

F, TX

(Notes 4, 6)

250 ns

Pulse Width of Spike Supressed t

(Note 7) 50 ns

Capacitive Load for Each Bus Line C

(Note 4) 400 pF

RST Pulse Width t

0.1 µs

16-pin TQFN 3.0

RST Rising Edge to MAX6946/MAX6947 ACK to Cancel Reset Run

Reset Run enabled, internal oscillator enabled

16-bump WLP 2.5

RST Rising Edge to MAX6946/MAX6947 ACK to Ensure Reset Run

Reset Run enabled, internal oscillator enabled

5.6

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design. Note 2: Port current is factory trimmed to meet a median sink current of 20mA and 10mA over all ports. The ΔI

OUT

specification

guarantees current matching between parts.

Note 3: A master device must provide a hold time of at least 300ns for the SDA signal (referred to V

of the SCL signal) in order to

bridge the undefined region of SCL’s falling edge.

Note 4: Not production tested. Guaranteed by design. Note 5: C

= total capacitance of one bus line in picoFarads; tRand tFare measured between 0.3 x VDDand 0.7 x VDD.

Note 6: I

SINK

≤ 6mA.

Note 7: Guaranteed by design. Input filters on the SDA and SCL inputs suppress noise spikes of less than 50ns.

SYMBOL

HD, STA

SU, STA

SU, STO

HD, DAT

SU, DAT

MIN TYP MAX

RSTRUN

+ 0.1C

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and

I/O Expander with PWM Intensity Control

_______________________________________________________________________________________ 5

STANDBY CURRENT (I

STBY

)

vs. TEMPERATURE

TEMPERATURE (°C)

STANDBY CURRENT (μA)

MAX6946/47 toc01

-40 -25 -10 5 20 35 50 65 80 95 110 125

0.4

0.8

1.2

1.6

2.0

VDD = 3.6V

VDD = 3.3V VDD = 2.7V

VDD = 2.25V

SUPPLY CURRENT (IDD)

vs. TEMPERATURE

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

MAX6946/47 toc02

-40-25-105 203550658095110125

VDD = 2.25V

VDD = 2.7V

VDD = 3.3V

VDD = 3.6V

STANDBY CURRENT (I

RST

)

vs. TEMPERATURE

TEMPERATURE (°C)

STANDBY CURRENT (μA)

MAX6946/47 toc03

-40-25-10 5 203550658095110125

VDD = 2.7V

VDD = 3.6V

VDD = 3.3V

VDD = 2.25V

DELTA SUPPLY CURRENT (I

DD20

)

vs. TEMPERATURE

TEMPERATURE (°C)

DELTA SUPPLY CURRENT (mA)

MAX6946/47 toc04

-40 -25 -10 5 20 35 50 65 80 95 110 125

2.0

2.4

2.8

3.2

3.6

4.0

VDD = 3.6V

VDD = 3.3V

VDD = 2.7V

VDD = 2.25V

DELTA SUPPLY CURRENT (I

DD20

)

vs. TEMPERATURE

TEMPERATURE (°C)

DELTA SUPPLY CURRENT (mA)

MAX6946/47 toc05

-40-25-10 5 203550658095110125

VDD = 3.6V

VDD = 3.3V

VDD = 2.7V

VDD = 2.25V

OUTPUT SINKING CURRENT

vs. V

EXT

- V

LED

AT 10mA

EXT

- V

LED

(V)

OUTPUT SINKING CURRENT (mA)

MAX6946/47 toc06

012345

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

OUTPUT SINKING CURRENT

vs. V

EXT

- V

LED

AT 20mA

EXT

- V

LED

(V)

OUTPUT SINKING CURRENT (mA)

MAX6946/47 toc07

012345

STAGGER PWM PORT WAVEFORMS

(OUTPUT REGISTERS SET TO 0x80)

MAX6946/47 toc08

1ms/div

PORT P0 2V/div

PORT P4 2V/div

PORT P7 2V/div

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and I/O Expander with PWM Intensity Control

6 _______________________________________________________________________________________

Pin Description

MAX6946/

MAX6947

MAX6946C

NAME FUNCTION

1B4 P0

2B3 P1

3C4 P2

4C3 P3

5D4 P4

I/O Ports. Configure P0–P4 as open-drain current sink outputs rated at 20mA (max), as CMOS-logic inputs, or as open-drain logic outputs. Connect loads to a supply voltage no higher than 7V.

6 D3 GND Ground

7D2 P5

8D1 P6

9C2 P7

10 C1 P8

11 B1 P9

I/O Ports. Configure P5–P9 as open-drain current sink outputs rated at 20mA (max), as CMOS-logic inputs, or as open-drain logic outputs. Connect loads to a supply voltage no higher than 7V.

External Oscillator Input

12 B2

Address Input. Sets the device slave address (see Table 10).

13 A1 RST Active-Low Reset Input

14 A2 VDD

P osi ti ve S up p l y V ol tag e. Byp ass V D D to GN D w i th a 0.1µF cer am i c cap aci tor .

15 A3 SCL I2C-Compatible, Serial-Clock Input

16 A4 SDA I2C-Compatible, Serial-Data I/O

—— EP

Exposed Pad on Package Underside. Connect to GND. Do not use as the main ground connection.

Block Diagram

OSC (MAX6946)

AD0 (MAX6947)

CURRENT REFERENCE

OSC*

EXTERNAL CLOCK INPUT*

INTERNAL

OSCILLATOR

RAMP-UP/RAMP-DOWN

PWM CONTROLLER

**MAX6946 ONLY.

**MAX6947 ONLY.

ADO**

SCL SDA RST

MAX6946 MAX6947

CONFIGURATION

2-WIRE SERIAL INTERFACE

CONTROLS

I/O REGISTER

I/O PORTS

P0 P1 P2 P3 P4 P5 P6 P7 P8 P9

Detailed Description

The MAX6946/MAX6947 general-purpose input/output (GPIO) peripherals provide 10 I/O ports, P0 to P9, controlled through an I2C-compatible serial interface. Use the 10 I/O ports as logic inputs, open-drain logic outputs, or constant-current sinks in any combination. Ports withstand 7V independent of the MAX6946/ MAX6947s’ supply voltage whether used as logic inputs, logic outputs, or constant-current sinks.

The MAX6946/MAX6947 feature shutdown and standby modes for low-power dissipation. The I/O ports feature pulse-width modulation (PWM) of the outputs and can stagger the PWM timing of the 10 port outputs in consecutively 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 resistors to provide the logic-high reference. Ports configured as open-drain logic outputs have a relatively weak sink capability, but are still adequate for normal logiclevel outputs. The weak drive means that the short-circuit current is low enough that inadvertently driving an LED from a port configured as a logic output is unlikely to damage the LED.

The MAX6946 features a fixed I2C slave address of 010 0000 and provides an OSC input to accept an external PWM clock input as an alternative to the internal PWM clock.

The MAX6947 features an AD0 input that uses two-level logic to select from two I2C slave addresses. The MAX6947 always uses the internal PWM clock.

The MAX6946/MAX6947 contain 22 internal registers (see Table 1). Use registers 0x00 to 0x09 to individually control ports P0 to P9. Registers 0x0A to 0x0D allow more than one port control register to be written with the same data to simplify software. Registers 0x0E and 0x0F do not store data, but return the port input status when read. Registers 0x10 to 0x15 configure and control the device operation.

MAX6946/MAX6947

10-Port, Constant-Current LED Driver and

I/O Expander with PWM Intensity Control

_______________________________________________________________________________________ 7

Table 1. Register Address Map

DESCRIPTION

ADDRESS

CODE

(HEX)

AUTO-

INCREMENT

ADDRESS

Port P0 output level or PWM 0x00 0x01

Port P1 output level or PWM 0x01 0x02

Port P2 output level or PWM 0x02 0x03

Port P3 output level or PWM 0x03 0x04

Port P4 output level or PWM 0x04 0x05

Port P5 output level or PWM 0x05 0x06

Port P6 output level or PWM 0x06 0x07

Port P7 output level or PWM 0x07 0x08

Port P8 output level or PWM 0x08 0x09

Port P9 output level or PWM 0x09 0x10

Write ports P0–P9 with same output level or PWM

Read port P0 output level or PWM

0x0A 0x10

Write ports P0–P3 with same output level or PWM

Read port P0 output level or PWM

0x0B 0x10

Write ports P4–P7 with same output level or PWM

Read port P4 output level or PWM

0x0C 0x10

Write ports P8 or P9 with same output level or PWM

Read port P8 output level or PWM

0x0D 0x10

Read ports P7–P0 inputs 0x0E 0x0F

Read p or ts P 9 and P 8 i np uts 0x0F 0x0E

Configuration 0x10 0x11

Ramp-down 0x11 0x12

Ramp-up 0x12 0x13

Output current ISET70 0x13 0x14

Output current ISET98 0x14 0x15

Global current 0x15 0x10

Factory reserved; do not write to this register

0x7D —

MAX6946/MAX6947

Configuration Register (0x10)

Use the configuration register to select PWM phasing between outputs, test fade status, enable hardware startup from shutdown, and select shutdown or run mode (Table 2).

Initial Power-Up

All control registers reset upon power-up (Table 3). Power-up status sets I/O ports P0 to P9 to high impedance, and puts the device into shutdown. The MAX6946/MAX6947 powers up in shutdown.

10-Port, Constant-Current LED Driver and I/O Expander with PWM Intensity Control

8 _______________________________________________________________________________________

Table 2. Configuration Register (0x10)

VALUE

FUNCTION

0 Internal oscillator enabled as PWM clock source

D7 OSC enable*

1 External oscillator input enabled as PWM clock source 0 RST does not change register data

D6 RSTPOR options

1 RST resets registers to POR (power-on reset) state

0 PWM outputs are in phase

D5 PWM stagger

1 PWM outputs stagger phase

0 Device not in hold-off

D4 Hold-off status**

1 Device in hold-off

0 Device not in fade-off

D3 Fade-off status**

1 Device in fade-off

0 Device not in ramp-up

D2 Ramp-up status**

1 Device in ramp-up

0 Reset Run disabled

D1 RST RUN enable

1 Reset Run enabled

0 Shutdown mode

D0 RUN enable

1 Run mode

*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

ADDRESS

Port P0–P9 output level or PWM

Port 0–9 high impedance

Configuration

0x10

Ramp-down/hold-off Fade/hold-off disabled 0x11

Ramp-up Disabled 0x12

PEAK

= 10mA for ports P7–P0 0x13

PEAK

= 10mA for ports P9, P8 0x14

Global current Full current 0x15

*Value is 0 for MAX6947 and 1 for MAX6946 bit.

S hutd ow n m od e, Reset Run d i sa b l ed

Output current ISET70

Output current ISET98

CODE (HEX)

0x00–0x09 11111

D7 D6 D5 D4 D3 D2 D1

0/1* 0000

00000

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