TECHNICAL DATA

LD1207

DESCRIPTION

The LD1207 is specifically designed for LED and LED DISPLAY derivers.
The LD1207 have 12/9 segment output lines, 7 to 4 grid output lines, one display memory, control circuit
and 3 line serial data interface.
This function are all incorporated into a single chip to build a highly reliable peripheral
device for a single chip microcomputer. It is very convenience to control for numeric display.
LD1207's pin assignments and application circuit are optimized for easy PCB Layout and cost saving
advantages.

FEATURES

· CMOS Technology
· Segment output line selection by command : 12 ~ 9
· Grid output line selection by command : 7 ~ 4
· Operation voltage : 5V
· Low Power Consumption
· 8-Step Dimming control by command
· Serial Interface for Clock, Data Input, Strobe Pins
· 24-pin, SOP Package

APPLICATION

· Segment LED display : VCR, DVD, MWO

TECHNICAL DATA

LD1207

BLOCK DIAGRAM

Segment

Driver /

Grid Driver

Serial

Data

Interface

OSC

Display

Memory

Control

Timing

Generator

Dimming Circuit

SG1

SG2

SG3

PIN CONFIGURATION

SG4

DIN

SG5

SG6

VDD

CLK

STB

SG7

SG8

SG9

SG10/GR7

SG11/GR6

OSC

SG12/GR5

GR4

GR3

GND

GR2

GR1

GND

VDD
SG12/GR5
SG11/GR6
SG10/GR7
SG9
SG8

GND
GR1
GR2
GR3
GR4

SG1

SG2
SG3
SG4
SG5
SG6
SG7

OSC
DIN
CLK
STB

VDD

7
8
9
10
11
12

1
2
3
4

18
17
16
15
14
13

24
23
22
21

TECHNICAL DATA

LD1207

PIN DESCRIPTION

Pin Name

OSC

DIN

CLK

STB

VDD

SG1 to SG9

SG10/GR7 to

SG12/GR5

GND

GR4 to GR1

I/O

Description

Pin No.

Oscillator Input Pin.

A resistor is connected to this pin and GND.

Data Input Pin.

This pin inputs serial data at the rising edge of

the shift clock (staring from the lower bit)

Clock Input Pin.

Rising edge trigger.

Strobe pin for Serial Interface.

The data input after the STB has fallen is

processed as a command.

When this pin is "HIGH", CLK is ignored.

Power Supply

5,18

Segment Output Pins(p-channel, open drain)

6~14

Segment Output Pin/ Grid Output Pin
(CMOS Output)

15~17

Ground Pin

19,24

Grid Output Pins (n-channel, open drain)

20~23

TECHNICAL DATA

LD1207

FUNCTIONAL DESCRIPTION

Commands

A command is the first byte (b0 to b7) inputted to LD1207 via DIN Pin after STB Pin has changed from
"HIGH" to "LOW" state. If for some reason the STB Pin is set "HIGH" while data or commands are
being transmitted, the serial communication is initialized, and the data/commands being transmitted are
considered invalid.

COMMAND 1 : DISPLAYMODE SETTING COMMANDS

LD1207 provides 4 display mode setting as shown in the diagram below: As stated earlier a
command is the first one byte(b0 to b7) transmitted to LD1207 via the DIN Pin when STB is
"LOW". However, for these commands, Bit No.3 to Bit No.6(b2 to b5) are ignored,
Bit No.7 & Bit No.8(b6 to b7) are given a value of "0".

The Display Mode Setting Commands determine the number of segments and grids be used
(1/4 to 1/7 duty, 12 to 9 segments). When these commands are executed, the display forcibly
turned off. A display command "ON" must be executed in order to resume display. If the same
mode setting is selected, no command execution is take place, therefore, nothing happens.

When Power is turned "ON", the 7-Grid, 9-Segment Mode is selected.

LSB

MSB

Display Mode Settings :
00 : 4 Grids, 12 Segments
01 : 5 Grids, 11 Segments
10 : 6 Grids, 10 Segments
11 : 7 Grids, 9 Segments

Don't Care

TECHNICAL DATA

LD1207

COMMAND 2 : DATA SETTING COMMANDS

The Data Setting Commands executes the Data Write Mode for LD1207. The Data Setting
Command, the bits5 and 6 (b4, b5) are ignored, bit7(b6) is given the value of "1" while bit8(b7) is
given the value of "0". Please refer to the diagram below.

When power is turned ON, bit 4 to bit 1 (b3 to b0) are given the value of "0".

LSB

MSB

Data Write Mode Settings :
00 : Write Data to Display Mode

Don't Care

Address Increment Mode Settings (Display Mode):
0 : Increment Address after Data has been Written
1 : Fixes Address

Mode Settings :
0 : Normal Operation Mode
1 : Test Mode

TECHNICAL DATA

LD1207

COMMAND 3 : ADDRESS SETTING COMMANDS

Address Setting Commands are used to set the address of the display memory. The address is
considered valid if it has a value of "00H" to 0DH". If the address is set to 0EH or higher, the
data is ignored until a valid address is set. When power is turned ON, the address is set at "00H".

Please refer to the diagram below.

LSB

MSB

Address : 00H to 0DH

Don't Care

Display Mode and RAM Address

Data transmitted from an external device to LD1207 via the serial interface are stored in the
Display RAM and are assigned addresses. The RAM Addresses of LD1207 are given below in
8 bit unit.

SG4 SG5

SG8 SG9

SG12

SG1

DIG1

00H

04H

00H

05H

01H

02H

03H

02H

04H

06H

07H

06H

08H

09H

08H

0AH

0BH

0AH

0CH

0DH

0CH

DIG2

DIG3

DIG4

DIG5

DIG6

DIG7

xxH

Lower 4 bits Higher 4 bits

TECHNICAL DATA

LD1207

COMMAND 4 : DISPLAY CONTROL COMMANDS

The Display Control Commands are used to turn ON or OFF a display. It also used to set the
pulse width. Please refer to the diagram below. When the power is turned ON, a 1/16 pulse
width is selected and the displayed is turned OFF.

LSB

MSB

Dimming Quantity Settings :
000 : Pulse width = 1/16
001 : Pulse width = 2/16
010 : Pulse width = 4/16
011 : Pulse width = 10/16
100 : Pulse width = 11/16
101 : Pulse width = 12/16
110 : Pulse width = 13/16
111 : Pulse width = 14/16

Don't Care

Display Settings :
0 : Display OFF
1 : Display ON

TECHNICAL DATA

LD1207

SWITCHING CHARACTERISTIC WAVEFORM

LD1207 Switching Characteristies Waveform is given below.

OSC

STB

CLK

DIN

10%

90%

CLK

setup

hold

CLK-STB

90%

10%

TZH

TLZ

THZ

CLK

TZL

CLK

(Clock Pulse Width) 400ns

t setup (Data Setup Time) 100ns
t

CLK-STB

(Clock - Strobe Time) 1

TZH

(Rise Time) 1

TZL

STB

(Strobe Pulse Width) 1

thold (Data Hold Time) 100ns
t

THZ

(Fall Time) 10

fosc = Oscillation Frequency

TlZ

<10

TECHNICAL DATA

LD1207

APLICATIONS

Display memory is updated by incrementing addresses. Please refer to the following diagram.

Command1

Command2

Command3

Data1

Data2

Command4

---------------------

STB

CLK

DIN

Where : Command 1 : Display Mode Setting

Command 2 : Data Setting Command
Command 3 : Address Setting Command
Data 1 to n : Transfer Display Data (14 Bytes max.)
Command 4 : Display Control Command

The following diagram shows the waveforms when updating specific addresses.

command2

command3

Data

command3

Data

STB

DIN

CLK

Where : Command 2 -- Data Setting Command

Command 3 -- Address Setting Command
Data -- Display Data

TECHNICAL DATA

LD1207

RECOMMENDED SOFTWARE PROGRAMMING FLOWCHART

START

SET

COMMAND 1

SET

COMMAND 2

SET

COMMAND 3

Clear Display RAM

(see Note 5)

SET

COMMAND 4

MAIN

PROGRAM

SET

COMMAND 1

SET

COMMAND2

SET

COMMAND 3

SET

COMMAND 4

INITIAL
SETTING

MAIN
LOOP

END

Note : 1. Command 1 : Display Mode Setting

2. Command 2 : Data Setting Commands
3. Command 3 : Address Setting Commands
4. Command 4 : Display Control Commands
5. When IC power is applied for the first time, the contents of the Display RAM are not defined : thus,

it is strongly suggested that the contents of the Display RAM must be cleared during the initial setting.

TECHNICAL DATA

LD1207

SOP 24L (300 MIL) THERMAL PERFORMANCE IN STILL AIR

Junction Temperature : 100

1200

966

616

IC Mounted Glass Epoxy PCB

IC Single

1000

Power Dissipation, Pd (mW)

800

600

400

200

-25

100

Ambient Temperature, Ta (

)

TECHNICAL DATA

LD1207

ABSOLUTE MAXIMUM RATINGS

(Unless otherwise stated, Ta=25

, GND=0V)

Parameter

Supply Voltage

Logic Input Voltage

Driver Output Current/Pin

Maximum Driver Output Current/Total

Symbol

ITOTAL

IOHSG

Rating

Units

-0.5 to +7.0

-0.5 to V

DD+

0.5

400

-50

+250

IOLGR

RECOMMENDED OPERATING RANGE

(Unless otherwise stated, Ta= -20 to +70

, GND=0V)

Parameter

Logic Supply Voltage

Dynamic Current (see Note)

High-Level Input Voltage

Low-Level Input Voltage

Symbol

DDdyn

VIL

Min.

4.5

0.8V

Typ.

Max.

Unit

5.5

0.3 V

Note : Test Condition : Set Display Control Commands = 80H (Display Turn OFF State)

TECHNICAL DATA

LD1207

ELECTRICAL CHARACTERISTICS

(Unless otherwise stated, V

=5V, GND=OV, Ta=25

Symbol

Test Condition

OHSG1

Min.

Typ.

Max.

Unit

Parameter

= V

- 1V

SG1 to SG9.

SG10/GR7 to SG12/GR5

OHSG2

= V

- 2V

SG1 to SG9.

SG10/GR 7 to SG12/GR5

-10

-14

-30

High-Level

Output Current

OLGR

-20

-25

-50

= 0.3V

GR1 TO GR4.

SG10/GR7 to SG12/GR5

TOLSG

Low-Level

Output Current

100

140

= V

- 1V

SG1 TO SG9.

SG10/GR7 to SG12/GR5

Segment

High-Level

Output Current

Tolerance

High-Level

Input Voltage

0.8VDD

Low-Level

Input Voltage

0.3VDD

Oscillation

Frequency

350

500

650

kHz

OSC

R = 51KOms

TECHNICAL DATA

LD1207

APPLICATION CIRCUIT

GND

VDD

SG12/GR5
SG11/GR6
SG10/GR7

SG9
SG8

GND
GR1
GR2
GR3
GR4

SG1

SG2
SG3
SG4
SG5
SG6
SG7

OSC
DIN
CLK
STB

VDD

S1
S2
S3
S4

MCU

G2
G3
G4

S12
S11

S10

G2
G3

S1
S2
S3
S4

S8
S9
S10
S11

S12

SEG1

SEG2
SEG3
SEG4
SEG5
SEG6
SEG7

DIGIT1
DIGIT2
DIGIT3

DIGIT4

SEG8
SEG9
SEG10
SEG11
SEG12

4-GRID X 12-SEGMENT

(COMMON CAHODE)

+5V

51K

0.1pF

Note : The capacitor (0.1uF) connected between the GND and VDD Pins must be located as near as
possible to the LD1207 chip.

COMMON CATHODE TYPE LED PANEL

SEG1

COM/ DIGITAL(GRID)

SEG2

SEG3

SEG4

SEG5

SEG6

SEG7

SEG8

TECHNICAL DATA

LD1207

Package Dimensions(24SOP)

D SUFFIX SOIC

(MS - 013AD)

Symbol

MIN

MAX

15.20

15.60

7.40

7.60

2.35

2.65

0.33

0.51

0.40

1.27

NOTES:

Dimensions A and B do not include mold flash or protrusion.

0.10

0.30

Maximum mold flash or protrusion 0.15 mm (0.006) per side

0.23

0.32

for A; for B 0.25 mm (0.010) per side.

10.00

10.65

0.25

0.75

1.27

9.53

Dimension, mm

C M

R x 45

SEATING

PLANE

0.25 (0.010) M T

-T-

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