ROHM BU2879AK Datasheet

1

Standard ICs

FL tube driver

BU2879AK

The BU2879AK is a driver IC for fluorescent displays. It is equipped with 26 high-voltage withstand outputs and can
display from 11 segments of 15 characters to 16 segments of 8 characters. This IC is equipped with a key scanning
function, and general-purpose input pins, and is ideal for front panels in VTRs and other equipment. A serial interface
allows functions to be controlled from a microcomputer.

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Applications

VCRs

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Absolute maximum ratings (Ta = 25°C, VSS = 0V)

Parameter
Applied voltage 1
Applied voltage 2
Input voltage
Power dissipation

V

DD

VEE

VIN
Pd

– 0.3 ~ + 7.0

V

DD + 0.3 ~ VDD – 40

– 0.3 ~ V

DD + 0.3

850

∗

V

Symbol Limits Unit

V
V

mW
Operating temperature Topr – 25 ~ + 75 °C
Storage temperature Tstg – 55 ~ + 125 °C

Note) Operation is not guaranteed at these values.
Note) Power dissipation is reduced by 8.5mW for each increase in Ta of 1°C over 25°C.

∗

When mounted on a 70 × 70 × 1.6mm glass epoxy board

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Features

1) High withstanding voltage output.

2) Display modes: 11S × 15G ~ 16S × 8G.

3) Variable display luminance (7 steps).

4) 3-wire serial interface.

5) Key scanning function (6 × 4).

6) Internal pull-down resistance
(high voltage withstand output).

7) QFP 44 package.

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Recommended operating conditions (Ta = 25°C, VSS = 0V)

Parameter

Operating power supply voltage 1 V

DD 4.5 5.0 5.5 V

Operating power supply voltage 2 VEE VDD – 37 VDD – 35 VDD – 0 V

Symbol Min. Typ. Max. Unit

2

Standard ICs BU2879AK

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Block diagram

CS SCK SI SO

S1

S11

S12

/ G15

S16

/ G11

VEE

SW4

SW1

K4

K1

OSC

G1

G10

VSS

8bit shift-REG.

16bit latch

SEGMENT Driver S / G Driver

KEY DATA

latch

(4 × 6)

V

DD

16bit × 15word

DISPLAY DATA RAM

OSC

CONTROL

LOGIC

4bit

data

GRID
Driver