Datasheet HT16562 Datasheet (Holtek Semiconductor Inc)

1/2 Duty VFD Digital Clock

Features

·

VFD display 12 hour clock function

·

Directly drive VFD panels at 1/2 Duty cycle

·

4.194304MHz crystal oscillation

·

Zero adjust function

General Description

The HT16562 provides direct drive to VFD panels to im
plement a 12 hour clock function. Obtaining its time
base from a 4.194304MHz crystal oscillation source
and in having a wide operating voltage due to its internal
voltage regulator, the device also contains a host of

Block Diagram

V C C
V S S

V

D D

V

D D

HT16562

·

Integrated voltageregulator permitswide 4Vto 18V
operating voltage range

·

Four levels of illumination control function

·

30-pin SSOP package

other features. These include a choice of adjustment

­modes, including single push increment or 2Hz fast for
ward functions. Additional features are provided in the
form of Blank control, Zero adjustment and four levels of
illumination control.

V o l t a g e R e g u l a t o r C i r c u i t

-

V D D

B L A N K

T E S T

D I M 1

D I M 2

V

D D

1 a , 3 a

A / C

Z A

H S

M S

X T

X T

V

D D

V

D D

V

D D

O s c i l l a t o r

T i m e A d j u s t m e n t

H o u r C o u n t e r

M i n u t e C o u n t e r

S e c o n d C o u n t e r

C o l o n

F r e q u e n c y

F r e q u e n c y D r i v e r C i r c u i t

B r i g h t n e s s A d j u s t m e n t

S e g m e n t

D e c o d e r

G r i d

D e c o d e r

S e g m e n t O u t p u t D r i v e r

G r i d O u t p u t D r i v e r

1 b , 3 b

1 c , 3 c

1 d , 3 d

1 e , 3 e

1 f , 3 f

1 g , 3 g

2 a , 2 d

2 b , 4 b , 4 c

2 c , c o l *

2 c , c o l ' *

2 e

2 f

2 g

6 4 H z

G R 1

G R 2

Note: ²*² col indicates a blink colon and col¢ indicates a continuous light colon.

Rev. 1.00 1 March 28, 2007

Pin Assignment

HT16562

G R 1

3 0

2 a , 2 d

2 9

2 b , 4 b , 4 c

2 8

2 f

2 7

2 c , c o l *

2 6

2 c , c o l ' *

2 5

2 e

2 4

2 g

2 3
2 2

1 d , 3 d

1 e , 3 e

2 1

1 c , 3 c

2 0

1 g , 3 g

1 9

1 f , 3 f

1 8

1 b , 3 b

1 7

1 a , 3 a

1 6

6 4 H z

T E S T

B L A N K

D I M 1

D I M 2

G R 2

V C C

V D D

V S S

A / C

M S

X T

X T

Z A

H S

1

2

3

4

5

6

7

8

9

1 0
1 1

1 2

1 3

1 4

1 5

H T 1 6 5 6 2

3 0 S S O P - A

Note: ²*² col indicates a blink colon and col¢ indicates a continuous light colon.

Pin Description

Pin Name I/O Description

VCC

VDD O Built-in regulator voltage output pin for the device internal circuits.

VSS

DIM1 I

DIM2 I

A/C

ZA

HS

MS

BLANK

XT

XT I

TEST I IC test pin - should be left open or kept at a low level

64Hz O 64Hz signal output pin for oscillation frequency adjustment

GR1 O

GR2 O

1a,3a ~
2b,4b,4c

High voltage power supply pin.

¾

Ground pin.

¾

Illumination level control pins.
Internally connected to pull-down resistors.

When the A/C

I

The reset pulse width should be more than 2ms.

pin is low, the internal circuits are reset.

Internally connected to a pull-high resistor.

Zero Adjustment pin.

I

Internally connected to a pull-high resistor.

Hour Adjustment pin.

I

Internally connected to a pull-high resistor.

Minute Adjustment pin.

I

Internally connected to a pull-high resistor.

When low the Blank input pin will extinguish the display.

I

Internally connected to a pull-down resistor.

O

Crystal oscillator pin

Grid output pins for 1/2 duty VFD

O Segment output pins for 1/2 duty VFD

Rev. 1.00 2 March 28, 2007

Approximate Internal Connections

HT16562

D I M 1 , D I M 2 , T E S T , B L A N K

V

C C

1 a , 3 a ~ 1 g , 3 g ; 2 a , 2 d ~ 2 g ;
G R 1 , G R 2

V

A / C , Z A , H S , M S

V

C C

D D

V S S

X T , X T

V

V S S

C C

( O s c i l l a t o r O u t p u t )

( O s c i l l a t o r I n p u t )

V

D D

V S S

X T

X T

V S S

6 4 H z

V

V S S

D D

Absolute Maximum Ratings

Logic Supply Voltage .................VSS-0.3V to VSS+6.5V

High Input Voltage .....................V

Logic Input Voltage ....................V

Driver Output Voltage..........................V

-0.3V to VCC+0.3V

SS

-0.3V to VDD+0.3V

SS

-0.3V to V

SS

CC

Driver Output Current (Grid Driver) ......-7mA to +20mA

Driver Supply Voltage .................V

High Output Voltage ..................V

Logic Output Voltage .................V

Driver Output Current (Segment Driver) -10mA to +2mA

Storage Temperature..........................-55°C to +150°C

Operating Temperature.........................-40°Cto+85°C

Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed
in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.

-0.3V to VSS+20V

SS

-0.3V to VCC+0.3V

SS

-0.3V to VDD+0.3V

SS

Recommended Operating Conditions

Symbol Parameter Min. Typ. Max. Unit

V

f

OSC

t

OP

CC

Power Supply Voltage 4

Oscillation Frequency

Operating Temperature

-40 ¾

¾

¾

4.194304

18 V

¾

MHz

85

°C

Rev. 1.00 3 March 28, 2007

HT16562

D.C. Characteristics

Symbol Parameter

V

V

I

IL1

I

IH1

I

IL2

I

IH2

I

IL3

I

OL

I

OH

I

SOL

I

SOH

I

GOL

I

GOH

I

CC

IH

IL

High Input Voltage

Low Input Voltage

Low-level Input Current 18V

Hi-level Input Current 18V

Low-level Input Current 18V XT pin low

Hi-level Input Current 18V XT pin high

Low-level Input Current 18V A/C,ZA,HS,MSpins low

Low-level Output current 12V

Hi-level Output current 12V

Driver Output Low Voltage
(All Segment outputs)

Driver Output High Voltage
(All Segment outputs)

Driver Output Low Voltage
(Grid1,Grid2)

Driver Output High Voltage
(Grid1,Grid2)

Dynamic Current Consumption 12V

Test Conditions

V

DD

=8Vto18V

V

¾

CC

=8Vto18V

V

¾

CC

Dim1, Dim2, BLANK
Test pins low

Dim1, Dim2, BLANK,
Test pins high

= 0.5V for 64Hz pin

V

OL

= 4.0V for 64Hz pin

V

OL

V

12V

12V

12V

12V

= 0.7V

SOL

V

= 11.3V

SOL

V

= 0.7V

SOL

V

= 11.3V

SOL

= 4.194304MHz,

f

OSC

Oscillator external
capacitors = 22pF

Conditions

VCC=12V, VSS=0V, Ta=-40°C~85°C

Min. Typ. Max. Unit

3.6

¾¾

,

-1 ¾¾mA

50

-3 ¾

-3 ¾

¾¾

1V

¾

200

3

3

V

mA

mA

mA

-200 ¾-50 mA

100

¾¾mA

¾¾-100 mA

15

¾¾-1.0

15

¾¾-15

¾¾

¾¾mA

mA

¾¾mA

mA

1.0 mA

Rev. 1.00 4 March 28, 2007

Functional Description

VFD Display Driving

The display can directly drive VFD signals dynamically
and does so at a 1/2 duty cycle rate. The clock will be
displayed in a 12-hour format with the hours ranging
from 1 to 12 and minutes from 00 to 59. If the most sig
nificant numeral is zero then the display will be extin
guished.

·

Grid and segment connections
A single 7-segment display is shown below showing
the illumination pattern for each numeral.

A

F

B

G

7 - S e g m e n t s

E

C

D



As the device is designed for clock applications, four
7-segment displays are required to display the correct
time output. The connections for the grids and seg
ments are shown below, however it should be noted
that the fourth segment only requires two of its seg
ments to be driven. Additionally it should be noted that
the colon can also be illuminated.

G R 2

4 c

d i g i t 4 d i g i t 3

3 a

3 f

4 b

3 b

3 g

3 e

3 c

3 d

Other Pin Functions

The external reset pin A/C
circuits of the device. When this pin is pulled low the de
vice will be reset, when the pin is allowed to go high, via
its internal pull-high resistor, then the display will indi

cate a ²1:00² output.

The BLANK

pin, if pulled low will extinguish the display.
Note that during the time when the BLANK
HS

,MSand ZA pins will be automatically disabled by

the device and have no function.

The 64Hz pin allows monitoring of the system frequency
to allow frequency adjustments to be executed. As the
name suggests, this output pin will continuously output
a frequency of 64Hz.

G R 1

2 a

2 f

2 b

2 g

2 e

2 c

2 d

d i g i t 2 d i g i t 1

1 f

1 e

c o l o n

c o l

c o l

is used to reset the internal

pin is low, the

1 a

1 b

1 g

1 c

1 d

The TEST pin is used during manufacturing for device
testing purposes and should not be connected to any
external circuitry.

Two illumination level set pins, DIM1 and DIM2, are pro
vided togive controlover thedisplay brightnesslevel, as

­shown in the following table.

-

Switch Pin

Name

Operating mode

Dim1 Dim2

L L f=256Hz, 1/2 duty (50% display)

H L f=256Hz, 1/4 duty (25% display)

L H f=256Hz, 1/8 duty (12.5% display)

H H f=256Hz, 1/16 duty (6.25% display)

Device Functions

·

Reset
Although the device is provided with an external reset
pin A/C

-

-

, the device will in fact reset itself when power
is applied, eliminating the need for external reset com
ponents. The usual provision of an external capacitor
is not required as an internal reset capacitor is inte
grated within the device.

·

Internal regulator
An internal regulator function is also integrated within
the device providing a stable voltage power supply
source for the internal circuits. This allows the device
to operate with a wide external power supply ranging
from 4V to 18V.

·

Chatter removal
The device contains circuits which are connected to
input pins HS

,MSand ZA to remove chatter of less

than 31.25ms.

·

-

-

Oscillator
The basic time base frequency for this device is deter
mined by an external 4.194304MHz crystal. When an
external crystal along with two small external capaci
tors are connected to the two oscillator XT pins, the in
ternal oscillator circuit will ensure generation of the
correct time base signals. The oscillation frequency,
although determined by the external crystal fre
quency, will also be influenced by the external capaci
tors, the crystal inherent capacitance and the residual
capacitance of the external PCB tracks. To ensure ac
curate frequency generation, the crystal specification
should be carefully consulted and the external capaci
tors and crystal should be placed as close to the de
vice as possible.

HT16562

-

-

-

-

-

-

-

-

-

-

-

Rev. 1.00 5 March 28, 2007

HT16562

Time Adjustment Operation

·

Hour/minute adjustment
Both the minutes and hour displays can be adjusted
separately or both together in a fast forward format.
The hour set pin, HS

, and the minutes set pin, MS, are
used to make these adjustments. Both of these pins
are connected to internal pull-high resistors. Each
time one of these lines is pulled low, the respective
hour or minute value will increment by one, also if the
line is continuously held low then the respective value
will increment automatically at a rate of 2Hz. Both val
ues will increment together if both lines are pulled low
simultaneously. Note that no carry functions will be im
plemented when either the hour or minute value over
flows.

·

Zero adjustment
A zero adjust function is also included within the de
vice and is controlled by the ZA

pin. This pin is con
nected to an internal pull-high resistor. Pulling this line
low will reset both the internal minutes and seconds
value, however the way in which the display is reset
depends upon the present value of the display. If the

Application Circuits

V

V

V

V

C C

C C

C C

C C

minute value is presently less than 30 the only the
second and minute values will be reset to zero and the
hour value remain unchanged. However if the minute
value is presently at a value of 30 or higher then when
the zero adjustment function is executed, a carry will
be implemented and the hour value will be incre

­mented by one. The following table illustrates a few
examples of this operation.

Zero Adjust Examples

-

-

-

Present Time After Zero Adjust

Hr. Min. Sec. Hr. Min. Sec.

1 30 00 2 00 00

2 00 00 2 00 00

-

-

2 29 59 2 00 00

2 30 00 3 00 00

2 59 59 3 00 00

3 29 59 3 00 00

V

C C

E F

S W 4

1 / 2 D u t y

V F D P a n e l

F -

1

2

F +

2 c , c o l

2 a , 2 d

4 b , 4 c , 2 b

2 f

2 e

2 g

3 d , 1 d

3 e , 1 e

3 c , 1 c

3 g , 1 g

3 f , 1 f

3 b , 1 b

3 a , 1 a

G R 1

G R 2

C 2

J u m p e r

S W 7

R 1

S W 8

S W 3

S W 6

S W 2

S W 5

S W 1

T E S T

D I M 1

D I M 2

B L A N K

A / C

Z A

H S

M S

V C C

V S S

2 c , c o l '

2 c , c o l

2 a , 2 d

4 b , 4 c , 2 b

3 d , 1 d

3 e , 1 e

3 c , 1 c

3 g , 1 g

3 f , 1 f

3 b , 1 b

3 a , 1 a

G R 1

G R 2

V D D

6 4 H z

J u m p e r
1

2

3

2 f

2 e

2 g

X T

X T

Y 1
4 . 1 9 4 3 0 4 M H z

C 1

Note: Capacitor C9 and C10 can adjust the accuracy of frequency

Rev. 1.00 6 March 28, 2007

Package Information

30-pin SSOP (300mil) Outline Dimensions

HT16562

3 0

A

1

C

C '

D

E

Symbol

Min. Nom. Max.

A 291

B 196

C9

C¢

390

D65

E

¾

F2

G22

H4

1 6

B

1 5

F

Dimensions in mil

G

H

=

¾

¾

¾

¾

¾

26

¾¾

¾

¾

a 0°¾8°

323

220

15

413

73

¾

37

8

Rev. 1.00 7 March 28, 2007

Preliminary

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Tel: [phone]
Fax: [phone]
Fax: [phone] (International sales hotline)

HT16562

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7th Floor, Building 2, No.889, Yi Shan Rd., Shanghai, China 200233
Tel: [phone]
Fax: [phone]
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Tel: [phone]
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Copyright Ó 2007 by HOLTEK SEMICONDUCTOR INC.

The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek as
sumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used
solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable
without further modification, nor recommends the use of its products for application that may present a risk to human life
due to malfunction or otherwise. Holtek¢s products are not authorized for use as critical components in life support devices
or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information,
please visit our web site at http://www.holtek.com.tw.

-

Rev. 1.00 8 March 28, 2007