SM1350 series

NIPPON PRECISION CIRCUITS--1

NIPPON PRECISION CIRCUITS INC.

High Tone Quality Melody LSI

OVERVIEW

The SM1350 series are single-chip high tone quality
melody ICs, fabricated using NPC's Molybdenum-
gate CMOS process. Melodies are selected in serial
or binary (parallel) mode, up to a maximum of 16
melody blocks. There are 4 sound generators
incorporated to produce 4 kinds of output tone
controlled by 16-tone data, making these ICs ideal
for mechanical clocks and similar applications where
high tone quality output is demanded.

FEATURES

Basic Functions
· 4.0 MHz oscillator frequency
· Power-save function

- Oscillator stopped when no output
- S0 to S3, MODE, LH pull-up resistors open

· BTL or A-class outputs
· Chattering prevention circuit (STN, STOP, S0

to S3)

· 10-bit D/A converter

Sound Generator Functions
· DWS (dual wave synthesis) sound generators
· 4 simultaneous sounds for 4 tones
· G2 to F#7 note range
· 16-tone programmable

Melody Functions
· Up to 16 programmable melodies (singly or in

medleys)

· 1024-step length (notes, rests, jumps, end

codes)

· Level hold/one-shot melody modes
· Serial/binary (parallel) select modes
· 4.8 to 605.6 tempo range in 127 steps
· 12 rhythm values

· Ties and slurs programmable

Control Signal Outputs
· BUSYN signal LOW during melody output
· CT signal output for external control

2.4 to 5.5 V supply voltage

Package
· 24-pin SSOP (SM1350

×××

)

Molybdenum-gate CMOS

PINOUT

(TOP VIEW)

PACKAGE DIMENSIONS

24-pin SSOP (Unit: mm)

ORDERING INFOMATION

D evice

Packag e

SM1350

×××

24pin SSOP

VDD

S0
S1
S2
S3

MODE

XT
XTN
TO
T3N
T2N
T1N
MSBN

STOP

MSB

STN

BUSYN

SP
SPN
VOL

ICN

VSS

0.7

0.8

0.36 0.10

10.20 0.30

10.05 0.20

0.10 0.10

2.10MAX

1.80 0.10

7.80 0.30

5.40 0.20

0.15

0.1

0.05

0 10

0.50 0.20

SM1350 series

NIPPON PRECISION CIRCUITS--3

PIN DESCRIPTION

N u m b e r

N a m e

I/O

State

1. U = pull-up resistor connection, SU : pull-up resistor connection only when melody output starts,

P = p-channel open drain, C = complementary output.
U or O = pull-up resistance or open drain (master slice)

Description

2. BTL/A-class output mode is selected by mask option.

VDD

Supply pin

Binary select mode: Phrase select pins.
Serial select mode: S0 and S1 control melody output.

MODE

Melody select mode control. Binary mode when LOW, and serial mode when HIGH.

Melody output mode control. One-shot when LOW, and level hold when HIGH.

STOP

U or O

One-shot melody mode: Melody output stop control.
Level hold melody mode: Invalid input.

STN

U or O

Melody start control

BUSYN

Busy output signal. LOW when a melody is output.

External control pulse output

ICN

Initialization clear input

VSS

Ground pin

VOL

Volume adjust control. Volume adjusted using an external resistor.

SPN

9-bit D/A converter output in BTL output mode.
VOL current output in A-class output mode.

BTL output mode: 9-bit D/A converter output.
A-class output mode: 10-bit D/A converter output.

MSB

BTL output mode: Signed-bit output. HIGH when no melody is output.

A-class output mode: BUSYIN input

MSBN

BTL output mode: Signed-bit output. HIGH when no melody is output.
A-class output mode: ENDN output. HIGH when no melody is output.

T1N

Test signal inputs

T2N

T3N

Test signal output. 62.5 kHz output when not in test mode.

XTN

Oscillator output

Oscillator input

SM1350 series

NIPPON PRECISION CIRCUITS--4

SPECIFICATIONS

Absolute Maximum Ratings

= 0 V

Recommended Operating Conditions

= 0 V

Master slice

Underlined entries are the default standard options. Throughout this datasheet, the standard options are
assumed unless otherwise specified.
U: pull-up resistance O: open input

P arameter

S y m b o l

Condition

Rating

Unit

Supply voltage

0.3 to 7.0

Input voltage

0.3 to V

+ 0.3

Storage temperature

stg

40 to 125

Power dissipation

650

Soldering temperature

sld

255

Soldering time

sld

P arameter

S y m b o l

Condition

Rating

Unit

m i n

typ

m a x

Supply voltage

2.4

5.5

Operating temperature

opr

S p e c i fi cations

Function Selected condition

Serial-mode melody selections

1 to 16

Melody output circuit

BTL / A-class

Level-hold melody select change retrigger

Yes / No

Pull-up/pull-down resistance

STN

U / O

STOP

U / O

SM1350 series

NIPPON PRECISION CIRCUITS--5

DC Characteristics

= 3 V, T

= 25

C, V

= 0 V, f

= 4.0 MHz

1.Supply voltage ratings shown are with oscillator running and all functions operating normally.
2.Clock frequency and duty cycle are ratings for the clock input on pin XT.
3.Output current when 20 k

volume control resistor is connected to VOL, and all D/A converter bits ON, measured using the circuit of the next page.

= 5 V, T

= 25

C, V

= 0 V, f

= 4.0 MHz

P arameter

S y m b o l

Condition

Rating

Unit

m i n

typ

m a x

Minimum operating supply voltage

MIN

2.4

Maximum operating supply voltage

MAX

5.5

Standby current consumption

STBY

No melody output

1.0

µA

Operating current consumption

BUSYN, CT, TO, SP, SPN,
MSB, MSBN all open

3.5

XT external capacitance

XTN external capacitance

Clock frequency

XTI

3.8

4.0

4.2

MHz

Clock duty cycle

XTI

S0 to S3, MODE, LH, STOP, STN, ICN
HIGH-level input voltage

0.3

S0 to S3, MODE, LH, STOP, STN, ICN
LOW-level input voltage

+ 0.3

S0 to S3, MODE, LH, STOP, STN, ICN
HIGH-level input current

= V

µA

S0 to S3, MODE, LH, STOP, STN, ICN
LOW-level input current

= V

µA

BUSYN, CT, TO HIGH-level output
current

OH1

= V

0.7

2.0

BUSYN, CT, TO LOW-level output current

OL1

= V

+ 0.7

2.0

MSB, MSBN HIGH-level output current

OH2

= V

0.7

3.0

MSB, MSBN LOW-level output current

OL2

= V

+ 0.7

3.0

SP, SPN output current

OH3

= V

+ 0.7

4.0

P arameter

S y m b o l

Condition

Rating

Unit

m i n

typ

m a x

Minimum operating supply voltage

MIN

2.4

Maximum operating supply voltage

MAX

5.5

Standby current consumption

STBY

No melody output

1.0

µA

Operating current consumption

BUSYN, CT, TO, SP, SPN,
MSB, MSBN all open

9.5

XT external capacitance

XTN external capacitance

Clock frequency

XTI

3.8

4.0

4.2

MHz

Clock duty cycle

XTI

S0 to S3, MODE, LH, STOP, STN, ICN
HIGH-level input voltage

0.3

S0 to S3, MODE, LH, STOP, STN, ICN
LOW-level input voltage

+ 0.3

S0 to S3, MODE, LH, STOP, STN, ICN
HIGH-level input current

= V

µA

SM1350 series

NIPPON PRECISION CIRCUITS--6

AC Characteristics

= 3 or 5 V, T

= 25

C, V

= 0 V

1.Oscillator start - up time = [time from when STN goes LOW to when TO goes HIGH] - 25.0

2.The time taken for fast damping to reduce the envelope to 0 level.

S0 to S3, MODE, LH, STOP, STN, ICN
LOW-level input current

= V

µA

BUSYN, CT, TO HIGH-level output
current

OH1

= V

0.7

2.0

BUSYN, CT, TO LOW-level output current

OL1

= V

+ 0.7

2.0

MSB, MSBN HIGH-level output current

OH2

= V

0.7

3.0

MSB, MSBN LOW-level output current

OL2

= V

+ 0.7

3.0

SP, SPN output current

OH3

= V

+ 0.7

7.7

1. Supply voltage ratings shown are with oscillator running and all functions operating normally.
2. Clock frequency and duty cycle are ratings for the clock input on pin XT.
3. Output current when 20 k

volume control resistor is connected to VOL, and all D/A converter bits ON, measured using the following circuit.

P arameter

S y m b o l

Condition

Rating

Unit

m i n

typ

m a x

Initialization clear time

ICW

1.0

µsec

STN pulsewidth t

STW

Pre-input option selected

81.9

msec

Oscillator start-up time

XST

500

µsec

Oscillator stop time

XEN

180.2

196.7

msec

D/A converter rise delay time

DAST

81.9

msec

D/A converter fall delay time

DAEN

180.2

196.7

msec

STN, STOP standby chattering time

CH1

81.9

msec

STN, STOP oscillator chattering time

CH2

Oscillator running

65.5

82.0

msec

S0 to S3 melody select chattering time

CH3

65.5

131.1

msec

MODE, LH read timing

15.9

µsec

S0 to S3 read timing

31.9

µsec

BUSYN fall delay time

BYST

8.2

msec

BUSYN rise delay time

BYEN

8.2

msec

Melody start delay time

PYST

16.4

msec

STOP pulsewidth t

STPW1

Pre-input option selected

81.9

msec

ENDN delay time

EDST

A-class output option

8.2

msec

ENDN pulsewidth

EDW

A-class output option

16.0

µsec

P arameter

S y m b o l

Condition

Rating

Unit

m i n

typ

m a x

VDD

VOL

VSS

20k

0.7V

SP,SPN

SM1350 series

NIPPON PRECISION CIRCUITS--7

FUNCTIONAL DESCRIPTION

Chattering Prevention

STN, STOP chattering prevention function

Standby Mode

The oscillator starts when STN goes from HIGH to
LOW in standby mode. Input data is received and

melody data output starts 81.9 ms after the oscillator
starts if STN is LOW.

Oscillator starts running

After the oscillator starts running, input data is
considered valid 81.9 ms after STN and STOP have

last changed state. Input data is considered invalid
for intervals less than 65.5 ms.

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 1. STN, STOP chattering prevention timing (standby mode)

STN

OSC

Input

Reception

81.9ms

Melody
Output

Internal

Clock

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 2. STN, STOP chattering prevention timing ( oscillator running)

81.9ms

65.5ms

STN or

STOP

Input

Reception

Internal

Clock

SM1350 series

NIPPON PRECISION CIRCUITS--8

S0 to S3 chattering prevention function

In binary select mode, S0 to S3 are sampled in sync
with the 15.26 Hz clock during level-hold melody
output. The chatter prevention function compares the
data sampled 65.5 ms after a data transition on S0 to
S3 with the data sampled 65.5 ms before the data
transition. If the 2 data samples are the same, then
the data transition is considered invalid. However, if
they are the not the same indicating a true transition

has occurred, melody output stops and only restarts
again after 2 consecutive identical melody select data
samples occur.

Note that except for the "Select change retrigger
[No]" master slice option and binary select mode
with level hold output, the S0 to S3 chattering
prevention circuit is disabled.

Initialization

When power on and ICN goes LOW, all pins and internal states are initialized to the states shown below. ICN
initialization has priority over all other inputs.

Output pins
· SP, SPN

Open

· MSB, MSBN

· CT

· BUSYN

Serial melody counter
Reset to first melody (S0 to S3 all 1)

Oscillator circuit
Stopped

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 3. S0 to S3 chattering prevention timing

15.26Hz

S0 to S3

65.5
ms

Melody
Output

SM1350 series

NIPPON PRECISION CIRCUITS--9

Melody Output Circuit

The volume control circuit comprises a P-channel
current-summing D/A converter, a built-in constant-
current source and an external variable resistor. The
circuit is set for either BTL output or A-class output
by master-slice option.

BTLoutput

The BTL output comprises a pair of 9-bit D/A
converters and 4 external transistors (2

NPN + 2

PNP) to drive a speaker.

A-class output circuit

The A-class output circuit comprises a single 10-bit
D/A converter with current output on SP. The D/A
converter MSB is set ON immediately after the
oscillator starts, and the current output that results is
the center point above and below which the converter
current output varies in response to the waveform

amplitude. The SP output is current-to-voltage
converted for connection to audio equipment or
amplifiers. In A-class output mode, the 4 sound
generator waveforms are time multiplexed, so an
integrating circuit must be connected between SP
and the amplifier to recover the signal.

Figure 4. BTL output circuit

VDD

VSS

VOL

MSB

MSBN

SPN

VSS

SPEAKER

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics.

Figure 5. A-class output circuit

VDD

VSS

VOL

BUSYN

AMP

SPEAKER

SM1350 series

NIPPON PRECISION CIRCUITS--10

Pin Functions

Binary select mode (MODE = LOW)

A melody (1 to 16) is selected according to the condition (H or L) of each 4 terminals (S0 to S3).

Note:Don't select any address with no melody recorded.

One-shot melody output (LH = LOW)

Melody

1st melody

9th melody

2nd melody

10th melody

3rd melody

11th melody

4th melody

12th melody

5th melody

13th melody

6th melody

14th melody

7th melody

15th melody

8th melody

16th melody

H : V

level, L : V

level

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 6. One-shot mode (binary select)

STN

S0 to S3

Melody
Output

SM1350 series

NIPPON PRECISION CIRCUITS--11

Level hold melody output (LH = HIGH)

If the "Select change retrigger [Yes]" mask option is
selected, a new melody starts playing from the

leading note when any of the S0 to S3 inputs changes
state.

Serial select mode (MODE = HIGH)

In serial select mode, the next melody is selected by
cycling through the melodies in the order #N

#N+1

...

#N when the STN input goes

LOW. The number of melodies in the cycle is set by

master-slice option. Note that when melody output is
stopped using the STOP input, the melody-select
counter increments.

One-shot melody output (LH = LOW)

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 7. Level hold mode (binary select) with "Select change retrigger [No]" mask option

STN

S0 to S3

Melody
Output

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 8. Level hold mode (binary select) with "Select change retrigger [Yes]" mask option

STN

S0 to S3

Melody
Output

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 9. One-shot mode (serial select)

STN

#N+1

#N+2

Melody
Output

SM1350 series

NIPPON PRECISION CIRCUITS--12

Level hold melody output (LH = HIGH)

S0, S1 melody output control

The melody selection in serial mode is controlled by S0 and S1 as shown in the following table. When S1 is
HIGH, S0 switches to a pull-up input configuration. The states of S0 and S1 are read in immediately after start-
up and does not change during melody output.

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 10. Level hold mode (serial select)

STN

#N+1

Melody
Output

Table 1. S0, S1 resistor and melody counter

S 0

S 1

M e l o d y counter

LOW

Increments when melody output stops

HIGH

LOW

No increment

HIGH

Increments when melody output starts

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 11. S0, S1 melody output control timing

STN

#N+1

#N+2

Serection
Counter

Melody
Output

#N+1

#N+2

SM1350 series

NIPPON PRECISION CIRCUITS--13

One-shot mode repeat function

In one-shot melody mode, the output repeats the
same melody while STN is LOW. When STN goes

HIGH, the output continues until the end of the
currently playing melody and then stops.

One-shot mode perpetual repeat function

If the score ROM end code is set to the jump code,
the melody will continue to play continuously once
one-shot mode starts.

STOP pin

One-shot output mode stops when STOP goes from
HIGH to LOW. The STOP input is ignored in level
hold output mode and is also ignored in one-shot

mode when STN is LOW. Note that even when
STOP is LOW, STN has higher priority.

CT pin

A pulse in sync with selected notes or rests is output
on CT. There are 2 modes for the output pulses--
pulse mode and hold mode.

Pulse mode

In pulse mode, a 16.4 ms pulse is output when a note
or rest occurs for which the corresponding CT data
in score ROM is set to 1.

Hold mode

In hold mode, the output pulse inverts when a note or
rest occurs for which the corresponding CT data in
score ROM is set to 1. The output goes LOW after

the start of a melody and when jumping to the
leading note of a melody.

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 12. One-shot melody repeat timing

STN

Melody
Output

Figure 13. CT pulse mode output

CT DATA

16.4msec

Figure 14. CT hold mode output

CT DATA

SM1350 series

NIPPON PRECISION CIRCUITS--14

Fast Damping

When melody output stops, the D/A converter output
amplitude does not fall to zero instantaneously,
instead the output converges to zero within a maxi-
mum of 8.2 ms to prevent noise being generated.

Also, when one-shot melody output mode is retrig-
gered, melody output restarts after the fast damping
interval.

Note: Refer to the "TIMING DIAGRAMS" section to confirm melody timing specifics

Figure 15. Fast damping timing

STOP

Melody
Output

8.2msec(max)

SM1350 series

NIPPON PRECISION CIRCUITS--15

Sound Generator

Synthesis mthod

The sound generators use the dual wave synthesis (DWS) method. The DWS method uses the envelope of 2
waveforms (main waveform and sub waveform) to synthesize the generated tone. Using this method makes
possible high tone quality output that faithfully reproduces the tones of real musical instruments.

Number of simultaneous sounds

The maximum number of tones that can be generated simultaneously is 4, making 4-part harmony

harmony

Generation possible (where each tone is derived from corresponding main and sub waveforms).

Sound range

The range of sounds covers 5 octaves from note G2 to F#7.

Waveform ROM

Waveforms are stored in a 10-bit

128-word

8-waveform capacity waveform ROM.

Number of programmable tones

The maximum number of programmable tones is 16. Note that 2 similar tones which have different envelope
settings are considered to be separate tones.

Built-in ROMs

The built-in ROMs comprise 3 types of ROM--waveform ROM containing waveform data, score ROM
containing musical score data, and parameter ROM containing envelope and jump data.

Figure 16.

Generated Sound

Sub Wave

Main Wave

Synthesize

Envelope

SM1350 series

NIPPON PRECISION CIRCUITS--16

Melodies

Number of melodies

The maximum number of program melodies is 16. Note that is the jump function is used to change the tone or
tempo during melody output, then the maximum number of melodies reduces by the number of times the jump
function was invoked.

Number of program steps

The maximum number of program steps that can be stored in score ROM (notes, rests, jump codes and end
codes) is 1024.

Tempo

The basic quarter note tempo can be set in the range 4.8 to 605.6 in multiples of 4.8.

Note (rest) rhythm values

There are 12 note rhythm values and 13 rest rhythm values that can be used to construct a melody. Also, 2 or
more notes can be combined using ties or slurs.

Table 2. Rhythm values Symbol Note Rest

Symbol

Note

Rest

SM1350 series

NIPPON PRECISION CIRCUITS--17

TIMING DIAGRAMS

(Refer to AC CHARACTERISTICS)

One-shot Melody Mode

Figure 17. One-shot mode (standby to melody start)

Figure 18. One-shot mode (retrigger to melody stop)

ICN

STN

OSC

MODE

S0 to S3

BUSYN

MELODY

OUTPUT

ICW

XST

STW

DAST

CH1

BYST

PYST

STN

STOP

MODE

S0 to S3

Melody
Output

BUSYN

ENDN

OSC

STW

CH2

PYST

STPW

CH2

BYEN

EDW

EDST

DEAN

XEN

SM1350 series

NIPPON PRECISION CIRCUITS--20

MEASUREMENT CIRCUIT

Note that circuit constants are reference values.

P a r a m e t e r

P i n n a m e

M e a s u r e m e n t s t a t e

Melody output circuit

BTL

STN

Pull-up

STOP

Pull-up

ICN

Pull-up

MODE

Pull-up

S0 to S3

Pull-up

VDD

MODE

STOP

STN

BUSYN

ICN

XTN

T3N

T2N

T1N

NSBN

MSB

SPN

VOL

VSS

0.1

200K

4.7 to 10

(Nonpolarity)

4MHz

SM1350 series

NIPPON PRECISION CIRCUITS--21

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 further 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 export controls on the distribution or dissemination of the products. Customers shall not export, directly or
indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies.

NIPPON PRECISION CIRCUITS INC.

4-3, 2-chome Fukuzumi
Koto-ku, Tokyo 135-8430, Japan
Telephone: 03-3642-6661
Facsimile: 03-3642-6698

NC9611BE

1998.10

NIPPON PRECISION CIRCUITS INC.

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