Rainbow-electronics MAX6959 Bedienungsanleitung PDF herunterladen (Seite 17)

Computing Power Dissipation

Determine the MAX6958/MAX6959 upper-limit power

dissipation (P

) with the following equation:

= (V+ ✕ I+) + (V+ - V

LED

) (DUTY ✕ I

SEG

✕ N)

where:

V+ = supply voltage

I+ = operating supply current

DUTY = duty cycle set by intensity register

N = number of segments driven (worst case is nine)

LED

= LED forward voltage at I

SEG

= peak segment current

= power dissipation, in mW if currents are in mA

Dissipation example:

SEG

= 23mA, N = 9, DUTY = 63/64, V

LED

= 2.2V,

V+ = 5.25V

= 5.25V (5.9mA) + (5.25V - 2.2V)

(63/64 ✕ 23mA ✕ 9) = 0.652W

For a 16-pin DIP package (T

= 1/0.0105 = +95.2°C/W

from Absolute Maximum Ratings), the maximum

allowed ambient temperature T

is given by:

J(MAX)

= T

+ (P

✕ T

) = +150°C

= T

+ (0.652 ✕ 95.2°C/W)

Therefore, T

= +87.9°C.

Power Supplies

The MAX6958/MAX6959 operate from a single 3V to

5.5V power supply. Bypass V+ with a 0.1µF capacitor

to GND, as close to the device as possible. Bypass V+

with an additional 10µF capacitor if the MAX6958/

MAX6959 are not close to the board input’s bulk

decoupling capacitor.

Chip Information

TRANSISTOR COUNT: 17,340

PROCESS: CMOS

MAX6958/MAX6959

2-Wire Interfaced, 3V to 5.5V, 4-Digit,

9-Segment LED Display Drivers with Keyscan

______________________________________________________________________________________ 17

Ordering Information (continued)

PART

TEMP

RANGE

SLAVE

ADDRESS

PIN-

PACKAGE

MAX6958BAEE -40°C to +125°C 0111001 16 QSOP

MAX6958BAPE -40°C to +125°C 0111001 16 DIP

MAX6959AAEE -40°C to +125°C 0111000 16 QSOP

MAX6959AAPE -40°C to +125°C 0111000 16 DIP

MAX6959BAEE -40°C to +125°C 0111001 16 QSOP

MAX6959BAPE -40°C to +125°C 0111001 16 DIP

CONFIGURATION

REGISTERS

DISPLAY RAM

AND HEX ROM

SCL

SDA

2-WIRE SERIAL INTERFACE

MULTIPLEX

LOGIC

4 LED DIGITS

KEYSCAN AND

LED

DRIVER

CURRENT

REFERENCE

MULTIPLEX

OSCILLATOR

PWM INTENSITY

CONTROL

PORT CONTROL

PORTS AND

KEYSCAN

IRQ

Functional Diagram

1 2 ... 12 13 14 15 16 17 18 19

MAX6958/MAX6959 1

Kommentare zu diesen Handbüchern

Keine Kommentare

Rainbow-electronics MAX6959 Bedienungsanleitung Seite 17

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Software Rainbow-electronics MAX6959