MAXIM MAX7219, MAX7221 User Manual

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General Description

The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs. The MAX7221 is compatible with SPI™, QSPI™, and MICROWIRE™, and has slewrate-limited segment drivers to reduce EMI.

A convenient 4-wire serial interface connects to all common µPs. Individual digits may be addressed and updated without rewriting the entire display. The MAX7219/MAX7221 also allow the user to select codeB decoding or no-decode for each digit.

The devices include a 150µA low-power shutdown mode, analog and digital brightness control, a scanlimit register that allows the user to display from 1 to 8 digits, and a test mode that forces all LEDs on.

For applications requiring 3V operation or segment blinking, refer to the MAX6951 data sheet.

Applications

Features

♦ 10MHz Serial Interface

♦ Individual LED Segment Control

♦ Decode/No-Decode Digit Selection

♦ 150µA Low-Power Shutdown (Data Retained)

♦ Digital and Analog Brightness Control

♦ Display Blanked on Power-Up

♦ Drive Common-Cathode LED Display

♦ Slew-Rate Limited Segment Drivers

for Lower EMI (MAX7221)

♦ SPI, QSPI, MICROWIRE Serial Interface (MAX7221)

♦ 24-Pin DIP and SO Packages

MAX7219/MAX7221

Serially Interfaced, 8-Digit LED Display Drivers

________________________________________________________________ Maxim Integrated Products 1

Typical Application Circuit

Pin Configuration

DOUT

SEG D

SEG DP

SEG EGND

DIG 4

DIG 0

DIN

TOP VIEW

SEG C

V+

ISET

SEG GDIG 7

DIG 3

DIG 2

DIG 6

SEG B

SEG F

SEG A

CLK

( ) MAX7221 ONLY

LOAD (CS)

DIG 1

DIG 5

GND

DIP/SO

MAX7219 MAX7221

19-4452; Rev 4; 7/03

PART

MAX7219CNG

MAX7219CWG

MAX7219C/D 0°C to +70°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

24 Narrow Plastic DIP

24 Wide SO

Dice*

Ordering Information

Ordering Information continued at end of data sheet.

*Dice are specified at T

= +25°C.

MAX7219ENG

MAX7219EWG

MAX7219ERG -40°C to +85°C

-40°C to +85°C

-40°C to +85°C 24 Narrow Plastic DIP

24 Wide SO

24 Narrow CERDIP

SPI and QSPI are trademarks of Motorola Inc. MICROWIRE is a trademark of National Semiconductor Corp.

Bar-Graph Displays

Industrial Controllers

Panel Meters

LED Matrix Displays

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

( ) MAX7221 ONLY

+5V

9.53k

SET

MOSI

µP

I/O

SCK

DIN

LOAD (CS)

CLK

GND

8-DIGIT µP DISPLAY

V+

DIG 0–DIG 7

MAX7219 MAX7221

GND

SEG A–G,

SEG DP

8 DIGITS

8 SEGMENTS

MAX7219/MAX7221

Serially Interfaced, 8-Digit LED Display Drivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V+ = 5V ±10%, R

SET

= 9.53kΩ ±1%, TA= T

MIN

to T

MAX

, unless otherwise noted.)

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.

Voltage (with respect to GND)

V+ ............................................................................-0.3V to 6V

DIN, CLK, LOAD, CS ...............................................-0.3V to 6V

All Other Pins.............................................-0.3V to (V+ + 0.3V)

Current

DIG0–DIG7 Sink Current................................................500mA

SEGA–G, DP Source Current.........................................100mA

Continuous Power Dissipation (T

= +85°C) Narrow Plastic DIP (derate 13.3mW/°C

above +70°C)..............................................................1066mW

Wide SO (derate 11.8mW/°C above +70°C).................941mW

Narrow CERDIP (derate 12.5mW/°C above +70°C) ...1000mW

Operating Temperature Ranges (T

MIN

to T

MAX

)

MAX7219C_G/MAX7221C_G ..............................0°C to +70°C

MAX7219E_G/MAX7221E_G ............................-40°C to +85°C

Storage Temperature Range .............................-65°C to +160°C

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

SET

= open circuit

All digital inputs at V+ or GND, TA= +25°C

Digit off, V

DIGIT

= V+

TA= +25°C, V+ = 5V, V

OUT

= (V+ - 1V)

All segments and decimal point on, I

SEG_

= -40mA

8 digits scanned

V+ = 5V, V

OUT

= 0.65V

TA= +25°C, V+ = 5V, V

OUT

= (V+ - 1V)

CONDITIONS

Operating Supply Current

µA150I+

V4.0 5.5V+Operating Supply Voltage

Shutdown Supply Current

µA-10I

DIGIT

Digit Drive Leakage (MAX7221 only)

%3.0∆I

SEG

Segment Drive Current Matching

mA/µs10 20 50∆I

SEG

/∆t

Segment Current Slew Rate (MAX7221 only)

330

I+

Hz500 800 1300f

OSC

Display Scan Rate

mA320I

DIGIT

Digit Drive Sink Current

mA-30 -40 -45I

SEG

Segment Drive Source Current

UNITSMIN TYP MAXSYMBOLPARAMETER

Segment off, V

SEG

= 0V µA1I

SEG

Segment Drive Leakage (MAX7221 only)

Digit off, V

DIGIT

= (V+ - 0.3V) mA-2I

DIGIT

Digit Drive Source Current (MAX7219 only)

Segment off, V

SEG

= 0.3V mA5I

SEG

Segment Drive Sink Current (MAX7219 only)

MAX7219/MAX7221

Serially Interfaced, 8-Digit LED Display Drivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V+ = 5V ±10%, R

SET

=9.53kΩ ±1%, TA= T

MIN

to T

MAX

, unless otherwise noted.)

VIN= 0V or V+

DOUT, I

SINK

= 1.6mA

DOUT, I

SOURCE

= -1mA

CONDITIONS

µA-1 1IIH, I

Input Current DIN, CLK, LOAD, CS

V0.4V

Output Low Voltage

V3.5V

Logic High Input Voltage

V0.8V

Logic Low Input Voltage

VV+ - 1V

Output High Voltage

UNITSMIN TYP MAXSYMBOLPARAMETER

DIN, CLK, LOAD, CS

V1∆V

Hysteresis Voltage

ns25t

CSS

CS Fall to SCLK Rise Setup Time (MAX7221 only)

ns100t

CLK Clock Period

ns50t

CLK Pulse Width High

ns50t

CLK Pulse Width Low

LOAD

= 50pF

ns25t

DIN Setup Time

ns50t

CSW

Minimum CS or LOAD Pulse High

ns0t

DIN Hold Time

ns25t

Output Data Propagation Delay

ns50t

LDCK

Load-Rising Edge to Next Clock Rising Edge (MAX7219 only)

ns0t

CSH

CLK Rise to CS or LOAD Rise Hold Time

ms2.25t

DSPD

Data-to-Segment Delay

LOGIC INPUTS

TIMING CHARACTERISTICS

MAX7219/MAX7221

Serially Interfaced, 8-Digit LED Display Drivers

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(V+ = +5V, TA = +25°C, unless otherwise noted.)

730

750

740

770

760

790

780

800

820

810

830

4.0 4.4 4.8 5.2 5.6 6.0

SCAN FREQUENCY vs.

POSITIVE SUPPLY VOLTAGE

MAX7219/21 01

POSITIVE SUPPLY VOLTAGE (V)

SCAN FREQUENCY (Hz)

012345

SEGMENT DRIVER OUTPUT CURRENT

vs. OUTPUT VOLTAGE

MAX7219/21 02

OUTPUT VOLTAGE (V)

OUTPUT CURRENT (mA)

SET

= 10k

Ω

SET

= 20k

Ω

SET

= 40k

Ω

MAX7219

SEGMENT OUTPUT CURRENT

MAX7219/21 03

5µs/div

10mA/div

MAXIMUM INTENSITY = 31/32

MAX7221

SEGMENT OUTPUT CURRENT

MAX7219/21 04

5µs/div

10mA/div

MAXIMUM INTENSITY = 15/16

MAX7219/MAX7221

Serially Interfaced, 8-Digit LED Display Drivers

_______________________________________________________________________________________ 5

Pin Description

Functional Diagram

NAME FUNCTION

1 DIN Serial-Data Input. Data is loaded into the internal 16-bit shift register on CLK’s rising edge.

2, 3, 5–8,

10, 11

DIG 0–DIG 7

Eight-Digit Drive Lines that sink current from the display common cathode. The MAX7219 pulls the digit outputs to V+ when turned off. The MAX7221’s digit drivers are high-impedance when turned off.

4, 9 GND Ground (both GND pins must be connected)

LOAD

(MAX7219)

18 ISET

Connect to VDDthrough a resistor (R

SET

) to set the peak segment current (Refer to Selecting

SET

Resistor section).

14–17,

20–23

SEG A–SEG G,

13 CLK

(MAX7221)

24 DOUT

Serial-Data Output. The data into DIN is valid at DOUT 16.5 clock cycles later. This pin is used to daisy-chain several MAX7219/MAX7221’s and is never high-impedance.

19 V+ Positive Supply Voltage. Connect to +5V.

Load-Data Input. The last 16 bits of serial data are latched on LOAD’s rising edge.

Chip-Select Input. Serial data is loaded into the shift register while CS is low. The last 16 bits of serial data are latched on CS’s rising edge.

Serial-Clock Input. 10MHz maximum rate. On CLK’s rising edge, data is shifted into the internal shift register. On CLK’s falling edge, data is clocked out of DOUT. On the MAX7221, the CLK input is active only while CS is low.

Seven Segment Drives and Decimal Point Drive that source current to the display. On the MAX7219, when a segment driver is turned off it is pulled to GND. The MAX7221 segment drivers are high-impedance when turned off.

SEG A–SEG G, DP

SEGMENT DRIVERS

CODE B

ROM WITH

BYPASS

SET

D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12

8x8

DUAL-PORT

SRAM

ADDRESS

LOAD (CS)

CLK

( ) MAX7221 ONLY

V+

SEGMENT

CURRENT

REFERENCE

DIN DOUT

DIG 0–DIG 7

DIGIT DRIVERS

SHUTDOWN REGISTER

MODE REGISTER

INTENSITY REGISTER

SCAN-LIMIT REGISTER

DISPLAY-TEST REGISTER

D13 D14 D15

INTENSITY

PULSE-

WIDTH

MODULATOR

MULTIPLEX

SCAN

CIRCUITRY

(MSB)(LSB)

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