SM1155 series
NIPPON PRECISION CIRCUITS--1
NIPPON PRECISION CIRCUITS INC.
Melody LSIs
OVERVIEW
The SM1155 series are CMOS melody LSIs that, together with a battery and piezoelectric buzzer, operate in
one of 3 melody modes determined by bonding options. They also feature an oscillator stop function in non-
play mode and a variable pull-down resistance function that responds to input levels in order to reduce power
consumption, reduce cost, and extend battery life, making them ideal in a wide range of applications including
the hold sound for telephones and toys.
FEATURES
I
Requires few external components
I
1.2 to 3.6V wide operating voltage range
I
Low power consumption
I
3 melody modes (bonding option)
I
Oscillator stop function in non-play mode
I
Power saving pull-down resistor built-in
I
RC oscillator circuit
I
Power-ON initialization function
I
Wide pitch dynamic range (G
3
to D
7
)
I
8-pin SOP package
ORDERING INFORMATION
PINOUT
(Top view)
PACKAGE DIMENSIONS
(Unit: mm)
D e vice
P a ck ag e
S M 1 1 5 5
1 S
8-pin SOP
S M 1 1 5 5
2 S
S M 1 1 5 5
3 S
1
T1
VSS
OUT
TC
4
2
3
OUT
VDD
8
7
6
5
55
TG
T2
4.4
0.2
6.2
0.3
5.2
0.3
0.695typ
1.5
0.1
1.27
0.4
0.1
0.12
M
0.10
0.05
0.05
0.15 - 0.05
+ 0.1
0.4
0.2
0 to 10
SM1155 series
NIPPON PRECISION CIRCUITS--2
PAD DESCRIPTION
SPECIFICATIONS
Absolute Maximum Ratings
Electrical Characteristics
T
a
= 25
C, V
SS
= 0V, V
DD
= 1.5V
N u m b e r
N a m e
i/o
Function
1
T 2
Test pins (must be open)
2
T 1
3
T G
ip
1
1. Built-in pull-down resistor (the resistance of the pull-down resistor varies with the applied voltage, as described in the Electrical Characteristics).
Melody mode control input
4
V S S
G r o u n d
5
O U T
o
Piezoelectric speaker driver outputs. Both pins are LOW in non-play m o d e. OUT is LOW and O U T is HIGH
during output for a musical rest note. Both pins are HIGH during the gap betwe e n musical notes.
6
O U T
7
V D D
Supply. The rear surface of the chip is V
D D
level.
8
T C
Test pins (must be open)
P arameter
S y m b o l
Condition
Rating
Unit
Supply voltage ra n g e
V
D D
-
V
S S
-
0.3 to 5.0
V
Input voltage ra n g e
V
IN
V
S S
-
0.2 to V
D D
+ 0.2
V
O p e rating temperature ra n g e
T
opr
-
20 to 80
C
Storage temperature ra n g e
T
stg
-
55 to 125
C
P arameter
S y m b o l
Condition
Rating
Unit
m i n
typ
m a x
O p e rating voltage
V
D D
1.2
1.5
3.6
V
Current consumption
1
1. Measurement circuit
I
D D 1
Non-play m o d e
0.01
0.3
A
Current consumption
2
I
D D 2
Melody modes: O U T, O U T open
2 5
5 0
A
T G L OW -level input voltage
V
IL
V
S S
+ 0.2
V
TG HIGH-level input voltage
V
IH
V
D D
0.2
V
T G L OW -level input current
I
IL
V
IL
= 0.4V
1.4
3.0
6.0
A
TG HIGH-level input current
I
IH
V
IH
= 1.5V
1.4
3.0
6.0
A
O U T, O U T L OW -level output current
I
O L
V
O L
= 0.75V
2.0
m A
O U T, O U T HIGH-level output current
I
O H
V
O H
= 0.75V
2.0
m A
Internal oscillator frequency
f
O S C
f
0
= 50kHz
2 0
+ 2 0
%
H
S M 1 1 5 5
1S
L evel hold 1
S M 1 1 5 5
2S
L evel hold 2
S M 1 1 5 5
3S
One-shot
L/open
S M 1 1 5 5
1S/ 2S/ 3S
Non-play
VDD
VSS
A
1.5V
2. Measurement circuit
VDD
TG
VSS
A
1.5V
SM1155 series
NIPPON PRECISION CIRCUITS--3
FUNCTIONAL DESCRIPTION
Melody Modes
When TG goes HIGH (V
DD
), melody play starts.
Level hold 1 (SM1155
1S)
When TG goes HIGH, melody play starts and continues while TG is held HIGH. When TG goes open circuit or
LOW, melody play stops, even if during mid melody.
Level hold 2 (SM1155
2S)
When TG goes HIGH, a single melody play starts. Melody play continues until the single melody ends or TG
goes open circuit or LOW, whichever occurs first.
1 TUNE
Oscillator
REPEAT
REPEAT
OUT
TG
500k
135k
135k
Pull-down resistance
(2-pin parallel resistance)
1 TUNE
Oscillator
OUT
TG
1M
270k
Pull-down resistance
270k
1M
270k
SM1155 series
NIPPON PRECISION CIRCUITS--4
One-shot (SM1155
3S)
When TG goes HIGH, a single melody play starts. Melody play continues until the melody ends, even if TG
goes open circuit or LOW mid melody. However, if the TG input goes HIGH again during melody play, the
melody play restarts from the beginning.
1 TUNE
Oscillator
OUT
TG
1M
270k
Pull-down resistance
270k
1M
270k
1 TUNE
1M
1M
270k
270k
From the begining
SM1155 series
NIPPON PRECISION CIRCUITS--5
Power-save Function
As shown in the preceding timing diagrams, the oscillator stops during non-play mode and the pull-down resis-
tance value changes in response to both HIGH-level and LOW-level inputs (power-save pull-down resistor) to
reduce power consumption and extend battery life.
Non-play oscillator stop function
When melody play ends, regardless of the state of TG, the internal oscillator stops and is placed in a standby
state. In this state, the current consumption, including input pin pull-down resistor current (I
IH
max), does not
exceed 3.3A.
Power-save pull-down resistor
The resistance of the TG input pull-down resistor changes in response to the input voltage. The pull-down
resistance is 500k
when the input is HIGH, and the pull-down resistance is 135k
when the input is LOW.
Furthermore, if a light-dependent resistor (CdS) cell is employed as a switch (the pull-down resistance is max-
imum when the CdS resistance is minimum (light) and the pull-down resistance is minimum when the CdS
resistance is maximum (dark)), the combined resistance can be increased, decreasing current consumption.
Musical Specifications
Maximum program steps
A maximum of 64 steps can be programmed into internal mask-programmable ROM. Each step represents
either a note (sound pitch and length), a rest note, or a jump. The maximum number of jumps is 7.
Note length (including rests)
Eight rhythm values, from sixteenth note to half note, for notes and rests can be programmed, as shown in the
following table.
Also, notes and rests longer than half notes and rests can be created using a tie to connect the notes. This
requires 2 program steps in ROM.
Tempo
The tempo for the standard quarter note can be selected from the following 16 options.
Pitch and scale
The SM1155 series devices support 3.5 octaves ranging from G
3
to D
7
, from which 15 notes can be selected to
form a scale.
Ty p e
C o d e
0
1
2
3
4
5
6
7
N o t e
R e s t
C o d e
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
=
6 9 7
3 4 8
2 3 2
1 7 4
1 3 9
1 1 6
99.4
8 7
77.3
69.6
63.3
5 8
53.5
49.7
46.4
43.5
SM1155 series
NIPPON PRECISION CIRCUITS--6
TYPICAL APPLICATION
The circuits below represent the standard connections for SM1155 series devices.
Circuit 1
Circuit 2
OUT
VDD
OUT
TG
VSS
Piezoelectric buzzer
OUT
VDD
OUT
TG
VSS
Piezoelectric buzzer
Circuit 3
OUT
VSS
VDD
OUT
TG
Piezoelectric buzzer
Light
SM1155 series
NIPPON PRECISION CIRCUITS--7
NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to
improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for
the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits
are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision
Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without fur ther testing or modification.
The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or
malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter,
including compliance with expor t controls on the distribution or dissemination of the products. Customers shall not expor t, directly or
indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies.
NIPPON PRECISION CIRCUITS INC.
4-3, Fukuzumi 2-chome
Koto-ku, Tokyo 135-8430, Japan
Telephone: 03-3642-6661
Facsimile: 03-3642-6698
NC0011AE
2000.08
NIPPON PRECISION CIRCUITS INC.
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