MBI5025

©Macroblock, Inc. 2003

Floor 6-4, No.18, Pu-Ting Rd., Hsinchu, Taiwan 30077, ROC.

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Current Accuracy

Between Channels Between ICs

Conditions

< ±3%

< ±6%

I OUT = 3 mA ~ 35 mA

Product Description

MBI5025 is designed for LED displays. As an enhancement of its predecessor, MBI5016,

MBI5025 exploits PrecisionDrive ™ technology to enhance its output characteristics. MBI5025 contains a serial buffer and data latches which convert serial input data into parallel output format. At MBI5025 output stage, sixteen regulated current ports are designed to provide uniform and constant current sinks for driving LEDs within a large range of Vf variations.

MBI5025 provides users with great flexibility and device performance while using MBI5025 in their system design for LED display applications, e.g. LED panels. Users may adjust the output current from 3 mA to 35 mA through an external resistor, R ext , which gives users flexibility in controlling the light intensity of LEDs. MBI5025 guarantees to endure maximum 17V at the output port. The high clock frequency, 25 MHz, also satisfies the system requirements of high volume data transmission.

OE SDO R-EXT VDD OUT9OUT10 OUT12 OUT13 OUT14 OUT15 Block Diagram

Terminal Description

Pin Configuration

LE

SDI CLK

SDO

OUT0 1OUT

OUT14 OUT15

Equivalent Circuits of Inputs and Outputs

LE terminal

terminal

CLK, SDI terminal

SDO terminal

OUT

Timing Diagram

Truth Table

CLK SDI

N = 0

1 2

3 4

5 6

7 8

9 10

11 12

13 14 15

LE

OFF ON OFF ON OFF ON OFF ON

OFF ON

SDO : don ’t care

1OUT OUT2 OUT3 OUT15

Maximum Ratings

Characteristic

Symbol Rating Unit Supply Voltage V DD 0~7.0 V Input Voltage V IN -0.4~V DD + 0.4

V Output Current I OUT +50 mA Output Voltage V DS -0.5~+20.0

V Clock Frequency F CLK 25 MHz GND Terminal Current I GND 1440 mA Operating Temperature T opr -40~+85 °C Storage Temperature

T stg

-55~+150 °C

CN – type 53.82 CNS – type

66.74 CD – type 49.81 CF – type 59.01 Thermal Resistance (On PCB, Ta=25°C)

CP – type

R th(j-a) 72.43

°C/W

Test Circuit for Electrical Characteristics

※If the devices are connected in cascade and t r or t f is large, it may be critical to achieve the timing required for data transfer between two cascaded devices.

Test Circuit for Switching Characteristics

L

V

V IH = V IL =

Timing Waveform

LE

SDI

CLK

SDO

OE

OUTn t of or OUTn OE

Constant Current

To design LED displays, MBI5025 provides nearly no variations in current from channel to channel and from IC to IC. This can be achieved by:

1) The maximum current variation between channels is less than ±3%, and that between ICs is

less than ±6%.

2) In addition, the current characteristic of output stage is flat and users can refer to the figure

as shown below. The output current can be kept constant regardless of the variations of LED forward voltages (Vf). This performs as a perfection of load regulation.

Adjusting Output Current

The output current of each channel (I OUT) is set by an external resistor, R ext. The relationship between I out and R ext is shown in the following figure.

Also, the output current can be calculated from the equation:

V R-EXT = 1.26V；I OUT = (V R-EXT / R ext ) x 15

where R ext is the resistance of the external resistor connected to R-EXT terminal and V R-EXT is the voltage of R-EXT terminal. The magnitude of current (as a function of R ext) is around 30mA at 620Ω and 15mA at 1260Ω.Package Power Dissipation (PD)

The maximum allowable package power dissipation is determined as P D(max) = (Tj – Ta) / R th(j-a). When 16 output channels are turned on simultaneously, the actual package power dissipation is P D(act) = (I DD x V DD) + (I OUT x Duty x V DS x 16). Therefore, to keep P D(act) ≤P D(max), the allowable maximum output current as a function of duty cycle is:

I OUT = { [ (Tj – Ta) / R th(j-a) ] – (I DD x V DD) } / V DS / Duty / 16, where Tj = 150°C.

Load Supply Voltage (V LED)

MBI5025 are designed to operate with V DS ranging from 0.4V to 0.8V (I OUT=5~35mA) considering the package power dissipating limits. V DS may be higher enough to make P D(act) > P D(max) when V LED = 5V and V DS = V LED– Vf, in which V LED is the load supply voltage. In this case, it is recommended to use the lowest possible supply voltage or to set an external voltage reducer, V DROP.

A voltage reducer lets V DS = (V LED– Vf) – V DROP.

Resistors or Zener diode can be used in the applications as shown in the following figures.

Package Outline

MBI5025CD Outline Drawing

MBI5025 16-bit Constant Current LED Sink Driver

January 2004, V0.9

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