HIGH TECH
CHIPS, INC.
Melody Generator
1.0 General description.
This circuit is designed to work as melody generator. HTC750 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. In Sleep mode HTC750 consumes less then few microamps
of current. One of possible uses of HTC750 is designing it in doorbell. This device was designed
using our proprietary melody storing scheme to optimize
PDIP, SOIC
internal memory usage. HTC750 can play up to four melodies.
It can directly drive piezo-electrical sound source or with use of
VDD
GND
1
8
external amplifier can drive speakers. Control output is
NU
MOUT
2
7
NU
CNTL
provided to control external relay or power switch. This output
3
6
D1
D0
4
5
goes high for duration of melody and could be used to control
the power to HTC750 and amplifier for duration of melody.
HTC750XXX
Possible uses are:
•
Musical doorbell.
•
Melody generator for alarm clock.
•
Musical toys.
•
Musical boxes for gifts, accessories or jewelry.
Features:
•
Single chip solution.
•
Minimum external components.
•
Four selectable melodies.
•
Minimum power consumption while in SLEEP mode.
Doorbell design using HTC750
S1
C1
R1
R2
100K
2
3
1
2
4
3
4
5
NU
NU
D1
D0
HTC750
1K
Q2
PNP
U1
VDD
MOUT
CNTL
GND
0.1uF
1
7
6
8
R3
C3
47uF
LS1
4.5V
100K
Q1
NPN
BT1
8ohm
04/30/00
1
HIGH TECH
CHIPS, INC.
2.0 Functional Description.
We will use schematics above to describe HTC750 operation. At power up HTC750 plays melody set
by dip-switch. After finishing melody it goes into sleep mode and drives all outputs to GND. In
prototypes we build using above schematics 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 HTC750 is cut
down and when this pushbutton is released then part will play the melody. One can use pushbutton
with normal open contacts but it could 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 and R2 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 HTC750 to save buttery.
This could be done by external relay. Quality of sound could be further enhanced if low pass filter is
added to output of HTC750. Please see Application note for HTC750.
Pin out description.
Abbreviations used: O - output, I - input, P - power.
Pin
1
2
3
4
5
6
7
8
Name
VDD
NU
NU
D1
D0
CNTL
MOUT
GND
I/O
P
I
I
I
I
O
O
P
Description
Power
Not Used
Not Used
Melody selection input.
Melody selection input.
Control output
Melody output
Ground
Notes
+2.5V to +5.5V
Tie it to GND or VDD.
Tie it to GND or VDD.
Tie it to GND or VDD.
Tie it to GND or VDD.
This output is driven high when part plays
melody. Can deliver up to 25mA current.
Signal on this output is square wave.
Connect to ground.
3.0 Melody selection with D[0:1]
D1
GND
GND
VDD
VDD
04/30/00
D0
GND
VDD
GND
GND
MELODY
Number 1
Number 2
Number 3
Number 4
2
HIGH TECH
CHIPS, INC.
This table shows melody played when D0 and D1 are tied to ground or power. Note that this
part comes with different sets of melodies and those melody samples will be made available
for download.
4.0 Electrical characteristics.
Voltage on VDD pin in respect to GND
Operational current with no external load
Current used in SLEEP mode
MOUT
output low voltage max (5mA load)
MOUT
output high voltage min (5mA source)
MOUT
maximum sink current
MOUT
maximum source current
CNTL
output low voltage max (5mA load)
CNTL
output high voltage min (5mA source)
CNTL
maximum sink current
CNTL
maximum source current
NOTES:
1. Those values are characterized but not tested.
5.0 Ordering information.
H
T
C
7
5
0
X
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.
MELODY
PART NUMBER.
+2.5 to +5.5V
3 mA
1
4uA
1
0.4V
1
VDD-0.7V
1
25mA
1
25mA
1
0.4V
1
VDD-0.7V
1
25mA
1
25mA
1
04/30/00
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HIGH TECH
CHIPS, INC.
6.0 Mechanical information.
8-Lead Plastic Dual In-line (P) – 300 mil (PDIP)
Units
INCHES*
Dimension Limits
MIN
NOM
Number of Pins
n
8
Pitch
p
.100
Top to Seating Plane
A
.140
.155
Molded Package Thickness
A2
.115
.130
Base to Seating Plane
A1
.015
Shoulder to Shoulder Width
E
.300
.313
Molded Package Width
E1
.240
.250
Overall Length
D
.360
.373
Tip to Seating Plane
L
.125
.130
Lead Thickness
c
.008
.012
Upper Lead Width
B1
.045
.058
Lower Lead Width
B
.014
.018
Overall Row Spacing
eB
.310
.370
α
Mold Draft Angle Top
5
10
Mold Draft Angle Bottom
β
5
10
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold
not exceed .010” (0.254mm)per side.
JEDEC Equivalent:MS-001
MAX
.170
.145
.325
.260
.385
.135
.015
.070
.022
.430
15
15
MILLIMETERS
MIN
NOM
MAX
8
2.54
3.56
3.94
4.32
2.92
3.30
3.68
0.38
7.62
7.94
8.26
6.10
6.35
6.60
9.14
9.46
9.78
3.18
3.30
3.43
0.20
0.29
0.38
1.14
1.46
1.78
0.36
0.46
0.56
7.87
9.40
10.92
5
10
15
5
10
15
flash protrusions. Mold flash or protrusions shell
04/30/00
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HIGH TECH
CHIPS, INC.
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
φ
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
α
0
12
15
0
12
15
Mold Draft Angle Bottom
β
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.
04/30/00
5
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