HIGH TECH
CHIPS, INC.
04/30/00 1
PDIP, SOIC
1
8
2
7
3
6
4
5
HTC751XX
VDD GND
SDAT MOUT
SCLK CNTL
D1 D0
Melody Generator
1.0 General description.
HTC751 is designed to play melodies stored in serial EEPROM. HTC751 can play any note in three
octave range which include octave three, four and five. User can write a melody and compile it with
Melody compiler, available for download in our web site. Melody compiler will generate binary file that
would be used to program the serial EEPROM. We went as far as defining our own proprietary
melody coding scheme that minimizes memory requirements
per given melody compared with popular schemes like MIDI,
Wave and even MPEG file formats. Our efforts will help users
to reproduce melodies at fraction of cost compared with other
melody coding schemes. HTC751 supports 2401, 2402, 2408
and 2416 serial EEPROM's available from Microchip, National
Semiconductors, Atmel and other semiconductor vendors.
HTC751 will play selected melody (selection is done by driving
D0 and D1 inputs to low or high value) and once melody is
finished it will enter power saving mode which we call Sleep mode. Note that In Sleep mode HTC751
consumes less then few microamps of current. One of possible uses of HTC751 is designing it in a
doorbell. HTC751 can play up to four melodies stored in serial EEPROM. It can directly drive piezo-
electrical sound element or a speaker with use of external amplifier. Control output is provided to
control external relay or power switch. This output goes high for duration of melody and could be
used to control the power to HTC751 and amplifier for duration of melody.
Features:
Flexible solution for storing and playing melodies.
Minimum external components.
Four selectable melodies easily extendible.
Minimum power consumption while in SLEEP mode.
Possible uses are:
Musical
doorbells.
Melody generator for alarm clock.
Musical
toys.
Musical boxes for gifts, accessories or jewelry.
2.0 Functional Description.
We will use schematics below to describe operation of HTC751. At power up HTC751 sets CNTL
output high and reads D0 and D1 inputs to select the melody to be played. Melody selection is done
by setting up the dip-switch. Next HTC751 will load melody to be played and starts playing it. After
finishing melody it goes into sleep mode and drives all outputs to GND. In prototypes we build using
schematics below current consumption was less then 10uA. This current is negligible enough to leave
circuit constantly powered on. When device is in Sleep mode only way of waking up the circuit is to
recycle power. This is done using S1 pushbutton. Note that we are using pushbutton with normal
closed contacts. When this pushbutton is activated power to HTC751 is cut down and when this
HIGH TECH
CHIPS, INC.
04/30/00 2
pushbutton is released then part will play the melody. One can use pushbutton with normal open
contacts but it will result partial reproduction of melody. Note the way CNTL output is used to save
energy during Sleep mode. Energy saving is achieved by cutting power to R1, R2 and R3 resistors
when part enters into Sleep mode and preventing battery discharge through those resistors when
associated dip-switch is on. T1 and T2 form simple current amplifier to drive 8-ohm speaker. Almost
any small signal transistor could be used in this amplifier. Note that this amplifier will introduce
additional distortions to amplified signal, because transistors are not biased. This is done intentionally
to simplify amplifier circuit and add one distinct character. This amplifier does not use any current
when its input is driven low. Any other amplifier circuit could be used as long as care is taken to shut
down the amplifier with CNTL output of HTC751 to save buttery.
This could be done by external relay or electronic switch. Please see Application note for HTC751.
Quality of sound could be further enhanced if low pass filter is added to output of HTC751.
Doorbell design using HTC751
Pin out description.
Abbreviations used: O - output, I - input, B- bi-directional, P
- power.
Pin
Name
I / O Description
Notes
1
VDD
P
Power
+2.5V to +5.5V
2
SDAT
B
Serial Data
Should be connected to SDAT of serial
EEPROM.
3
SCLK
O
Not Used
Should be connected to SCLK of serial
EEPROM.
4
D1
I
Melody selection input.
Tie it to GND or VDD.
5
D0
I
Melody selection input.
Tie it to GND or VDD.
6
CNTL
O
Control output
This output is driven high when part plays
melody. Can deliver up to 25mA current.
7
MOUT
O
Melody output
Signal on this output is square wave.
8
GND
P
Ground
Connect to ground.
C1
0.1uF
Q1
NPN
Q2
PNP
LS1
8ohm
C3
47uF
R4
1K
B1
3XAA
S3
SW
1
2
4
3
U1
2402
A0
1
A1
2
A2
3
SCL
6
SDA
5
VDD
8
VSS
4
R3
100K
R2
100K
R1
10K
U2
HTC751
SDAT
2
SCLK
3
MOUT
7
VDD
1
CNTL
6
D1
4
D0
5
GND
8
HIGH TECH
CHIPS, INC.
04/30/00 3
3.0 Melody selection with D[0:1]
D1
D0
MELODY
GND
GND
Number 1
GND
VDD
Number 2
VDD
GND
Number 3
VDD
GND
Number 4
This table shows melody played when D0 and D1 are tied to ground or power. Note that this
part can play four different sets of melodies.
4.0 Electrical characteristics.
Voltage on VDD pin in respect to GND
+2.5 to +5.5V
Operational current with no external load
3 mA
1
Current used in SLEEP mode
4uA
1
MOUT
output low voltage max (5mA load)
0.4V
1
MOUT
output high voltage min (5mA source)
VDD-0.7V
1
MOUT
maximum sink current
25mA
1
MOUT
maximum source current
25mA
1
CNTL
output low voltage max (5mA load)
0.4V
1
CNTL
output high voltage min (5mA source)
VDD-0.7V
1
CNTL
maximum sink current
25mA
1
CNTL
maximum source current
25mA
1
NOTES:
1. Those values are characterized but not tested.
5.0 Ordering information.
H
T
C
7
5
1
X
X
OPTIONAL: Temperature range:
C = 0
o
C to +70
o
C , I = - 40
o
C to + 85
o
C.
PACKAGE:
S 208 mil SOIC
D 300 mil PDIP.
PART NUMBER.
HIGH TECH
CHIPS, INC.
04/30/00 4
6.0 Mechanical information.
8-Lead Plastic Dual In-line (P) 300 mil (PDIP)
Units
INCHES*
MILLIMETERS
Dimension Limits
MIN
NOM
MAX
MIN
NOM
MAX
Number of Pins
n
8
8
Pitch
p
.100
2.54
Top to Seating Plane
A
.140
.155
.170
3.56
3.94
4.32
Molded Package Thickness
A2
.115
.130
.145
2.92
3.30
3.68
Base to Seating Plane
A1
.015
0.38
Shoulder to Shoulder Width
E
.300
.313
.325
7.62
7.94
8.26
Molded Package Width
E1
.240
.250
.260
6.10
6.35
6.60
Overall Length
D
.360
.373
.385
9.14
9.46
9.78
Tip to Seating Plane
L
.125
.130
.135
3.18
3.30
3.43
Lead Thickness
c
.008
.012
.015
0.20
0.29
0.38
Upper Lead Width
B1
.045
.058
.070
1.14
1.46
1.78
Lower Lead Width
B
.014
.018
.022
0.36
0.46
0.56
Overall Row Spacing
eB
.310
.370
.430
7.87
9.40
10.92
Mold Draft Angle Top
5
10
15
5
10
15
Mold Draft Angle Bottom
5
10
15
5
10
15
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash protrusions. Mold flash or protrusions shell
not exceed .010" (0.254mm)per side.
JEDEC Equivalent:MS-001
HIGH TECH
CHIPS, INC.
04/30/00 5
8-Lead Plastic Small Outline (SM) Medium, 208 mil (SOIC)
Units
INCHES
*
MILLIMETERS
Dimension Limits
MIN
NOM
MAX
MIN
NOM
MAX
Number of Pins
n
8
8
Pitch
P
.050
1.27
Overall Height
A
.070
.075
.080
1.78
1.97
2.03
Molded Package Thickness
A2
.069
.074
.078
1.75
1.88
1.98
Standoff
A1
.002
.005
.010
0.05
0.13
0.25
Overall Width
E
.300
.313
.325
7.62
7.95
8.26
Molded Package Width
E1
.201
.208
.212
5.11
5.28
5.38
Overall Length
D
.202
.205
.210
5.13
5.21
5.33
Foot Length
L
.020
.025
.030
0.51
0.64
0.76
Foot Angle
0
4
8
0
4
8
Lead Thickness
c
.008
.009
.010
0.20
0.23
0.25
Lead Width
B
.014
.017
.020
0.36
0.43
0.51
Mold Draft Angle Top
0
12
15
0
12
15
Mold Draft Angle Bottom
0 12
15
0
12
15
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash protrusions. Mold flash or
protrusions shell not exceed .010" (0.254mm)per side.
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