3471AB_ND15011E00

SM3471AB
Interpolation Encoder IC
OVERVIEW
The SM3471 is an interpolation IC for encoders. It accepts displacement detection, 2-phase analog signals (A and B phases) and a zero
point detection analog signal (Z phase) from an encoder, interpolates the signals by a specified interpolation factor, and outputs
corresponding 2-phase digital signals (A and B phases) and a zero point detection digital signal (Z phase).
FEATURES
▪ Interpolation switching function: ×2, 4, 8, 16 (selectable)
▪ Input frequency: 300kHz (max)
▪ Output frequency: 2.5MHz (max)
▪ Supply voltage: 2.7 to 5.5V
▪ Operating temperature range: –40 to +125°C
▪ Package: QFN24 (size: 4mm × 4mm)
ORDERING INFORMATION
Device
Package
SM3471AB-G*1
24 pin QFN
*1. “-G” option code lead-free package
0.2 S B
PACKAGE DIMENSIONS
4.00±0.1
0.2 S A
0.75
0.75
A
C0.11
0.50
2.40 ±0.1
0.45±0.1
0.65 MAX
0.05 MAX
0 MIN
0.22±0.05
// 0.2 S
3
.0
0.15
2.40 ±0.1
C0
4.00±0.1
B
0.50
0.22±0.05
0.05
M
S AB
S
0.08 S
[unit:mm]
SEIKO NPC CORPORATION - 1
SM3471AB
PINOUT
QFN24 package
(Top view)
24
23
22
21
20
19
VSS
1
18 VREF
NC
2
17 NC
VDD
3
16 NC
25
25TP
DA
4
DB
5
14 SEL0
DZ
6
13 ZSEL
7
8
9
10
15 SEL1
11
12
PIN DESCRIPTION
Pin No.
Name
I/O*1
1
VSS
-
Ground
2
NC
-
No connection
3
VDD
-
Power supply
4
DA
O
Displacement detector signal output (A)
5
DB
O
Displacement detector signal output (B)
6
DZ
O
Zero point detector signal output (Z)
7
NC
-
No connection
8
NC
-
No connection
9
NC
-
No connection
10
VSS
-
Ground
11
VSS
-
Ground
12
NC
-
No connection
13
ZSEL
I
Z-phase output timing setting input with pull-down resistor
14
SEL0
I
Interpolation setting input with pull-down resistor
15
SEL1
I
Interpolation setting input with pull-down resistor
16
NC
-
No connection
17
NC
-
No connection
18
VREF
O
VDD/2 level voltage output
19
ZN
I
Zero point detector inverse-phase signal input
20
Z
I
Zero point detector signal input
21
AN
I
Displacement detector signal (–cos) input
22
A
I
Displacement detector signal (cos) input
23
BN
I
Displacement detector signal (–sin) input
24
B
I
Displacement detector signal (sin) input
25
TP
-
Thermal pad. Connect to VSS or leave OPEN.
Description
*1. I: Input pin O: Output pin I/O: Input/Output pin
VSS terminals number 1, 10 and 11 must be connected to the ground on the mounting board.
SEIKO NPC CORPORATION - 2
SM3471AB
BLOCK DIAGRAM
VDD
A
AN
B
AMP
BN
Interpolation
Buffer
DA
Buffer
DB
Buffer
DZ
Z
ZN
SEL0
SEL1
ZSEL
Vref
VREF
VSS
SPECIFICATIONS
Absolute Maximum Ratings
VSS=0V
Parameter
*1
Supply voltage 1
*1,*4
Input voltage
Symbol
Condition
Rating
Unit
VDD
VDD pin
–0.3 to +6.5
V
VIN
*1,*4
Output voltage
*2
VOUT
Output current
IOUT
Junction temperature*3
Tj
*1
Power dissipation
*5
Storage temperature
PD
Tstg1
*6
Input pins
–0.3 to VDD+0.3
V
*7
–0.3 to VDD+0.3
V
*7
-1.8 to 1.8
mA
+150
°C
1570
mW
–40 to +125
°C
Output pins
Output pins
*8
Ta=25°C
*1. Parameters must not exceed the ratings, not even momentarily. If the rating is exceeded, there is a risk of IC failure, deterioration in characteristics,
and decrease in reliability.
*2. Parameter must not exceed the rating on average. If the rating is exceeded, there is a risk of IC failure, deterioration in characteristics and decrease in
reliability.
*3. Parameter should not exceed the rating. If the rating is exceeded, there is a risk of deterioration in characteristics and decrease in reliability.
*4. VDD value is the recommended operating voltage rating.
*5. Stored separately without packing material in Nitrogen or vacuum atmosphere.
*6. SEL0, SEL1, ZSEL, A, AN, B, BN, Z, and ZN terminals.
*7. DA, DB, and DZ terminals.
*8. 114.3×76.2×1.6mm, 150% wiring ratio, FR-4 4-layer board (with thermal pad connections). Dissipation will vary due to differences in board
specifications and footprint pattern.
SEIKO NPC CORPORATION - 3
SM3471AB
Power Dissipation
2000
Power dissipation Pd [mW]
1800
1600
1400
1200
1000
800
600
400
200
0
0
25
50
75
100
125
Operating temperature Ta [°C]
Recommended Operating Conditions
The recommended operating conditions are the conditions for which the electrical characteristics are guaranteed.
VSS=0V
Parameter
Symbol
Supply voltage
Logic input voltage
*1
Analog Input voltage range
*1
Input signal amplitude
Condition
MIN
TYP
MAX
Unit
VDD
VDD pin
2.7
-
5.5
V
VIN1
SEL0, SEL1, ZSEL pins
VSS
-
VDD
V
VIN2
A, AN, B, BN, Z, and ZN pins
1
-
VDD–1
V
A, AN, B, BN, Z, and ZN pins
0.6
-
-
Vpp
A-AN center offset
B-BN center offset
VDD=5.0V, 25°C
-25
-
25
mV
VINPP
Input offset voltage*2
VOFFSET
Input signal frequency
FIN
Operating temperature range
Ta
A, AN, B, BN, Z, and ZN pins
-
-
300
kHz
–40
-
+125
°C
Note. Operation outside the recommended operating conditions may adversely affect reliability. Use only within specified ratings.
*1 Definition VIN2 and VINPP
*2 Definition VOFFSET
A, AN(B, BN) each ±12.5mV
⇒Absolute value:25mV
VDD
VIN2(max)=VDD-1V
A(B)
VIN2
VINPP
VIN2(min)=1
AMP
AN(BN)
0V
* Higher accuracy is obtained by increasing signal amplitude VINPP,
so largest value within the input voltage range is recommended.
SEIKO NPC CORPORATION - 4
SM3471AB
Electrical Characteristics
VDD=2.7 to 5.5V, VSS=0V, Ta=–40 to +125°C unless otherwise noted
Parameter
Symbol
*1
Current consumption
Logic input voltage*2
Logic input current*2
Output voltage*3
Output frequency
IDD
Condition
No load
MIN
TYP
MAX
Unit
mA
-
15
25
VIH
0.7VDD
-
VDD
VIL
VSS
-
0.3VDD
IIH
VIN=VDD, Ta=25°C
20
-
200
IIL
VIN=VSS, Ta=25°C
–1
-
-
V
μA
VoutH
Iout = +1.5mA
VDD–0.4
-
-
VoutL
Iout = –1.5mA
-
-
0.3
-
-
2.5
MHz
VDD=5.0V,
16x interpolation,
Input ideal sin(cos) wave,
10kHz input frequency,
3.0Vppinput amplitude
-
-
6
Degrees
0.1VDD to 0.9VDD, CL=20pF
-
-
10
ns
fout
*4
Angular error
(max – min)
ARAL
Rise/Fall time
trf
V
*1. Typical conditions: VDD=5V, Ta=25°C, 8x interpolation, FIN=10kHz
*2. SEL0, SEL1, and ZSEL terminals.
*3. DA, DB, and DZ terminals.
*4. The angular error expresses the variation from the ideal phase difference of interpolation outputs DA and DB as a phase difference of the input period.
Converting 6° and expressing as a percentage of the output period gives 26.6% using equation (1) below.
6 deg× 16 x
= 26.6%
360 deg
(1)
(where 16x is the interpolation factor)
TPIN : input period
A(cos)
B(sin)
TPOUT : output period
DA
16x
multiplier
DB
TPOUT : output period
Conversion to output period reference
TPOUT = TPIN / Multiplier = 360deg
DA
ARAL_OUT = 6deg × 16 = 96deg
DB
=
ARAL_OUT
6deg × 16
360deg
= 26.6%
SEIKO NPC CORPORATION - 5
SM3471AB
FUNCTIONAL DESCRIPTION
Interpolation Circuit
The interpolation circuit passes the input signals, through a resistance network divider, converts the signals to binary using comparators,
and outputs 2-phase digital signals corresponding to the interpolation factor selected by register data using logical operation processing.
The interpolation factor is set using input level of SEL0 and SEL1 terminals.
SEL1
SEL0
Interpolation factor
L
L
2
L
H
4
H
L
8
H
H
16
ANsig(-cos)
Buffer
DA
Buffer
DB
Buffer
DZ
Asig(cos)
BNsig(-sin)
Resistor
Ladder
Comparator
Logic
Bsig(sin)
Zsig
Comparator
SEL0, SEL1
Output Reference voltage
VREF terminal outputs the VDD/2 voltage as a reference voltage to use in single-ended input.
SEIKO NPC CORPORATION - 6
SM3471AB
Timing Diagrams
Interpolation Function and Z-phase Input/Output Timing
DZ signal timing is settable by ZSEL terminal.
interpolation x2 CW
interpolation x2CCW
T
B_INPUT
(Sin)
A_INPUT
(Cos)
Z_INPUT
A_INPUT
(Cos)
Max
Max
Z_INPUT
DA
DA
DB
DB
DZ ZSEL=1
DZ ZSEL=1
DZ ZSEL=0
DZ ZSEL=0
interpolation x4 CW
A_INPUT
(Cos)
Max
Max
Z_INPUT
DA
DA
DB
DB
DZ ZSEL=1
DZ ZSEL=1
DZ ZSEL=0
DZ ZSEL=0
interpolation x8 CW
Max
Max
interpolation x8 CCW
T
B_INPUT
(Sin)
T
B_INPUT
(Sin)
A_INPUT
(Cos)
A_INPUT
(Cos)
Max
Max
Z_INPUT
DA
DA
DB
DB
DZ ZSEL=1
DZ ZSEL=1
DZ ZSEL=0
DZ ZSEL=0
interpolation x16 CW
Max
Max
interpolation x16 CCW
T
B_INPUT
(Sin)
T
B_INPUT
(Sin)
A_INPUT
(Cos)
Z_INPUT
Max
T
B_INPUT
(Sin)
A_INPUT
(Cos)
Z_INPUT
Max
interpolation x4 CCW
T
B_INPUT
(Sin)
Z_INPUT
T
B_INPUT
(Sin)
A_INPUT
(Cos)
Max
Max
Z_INPUT
DA
DA
DB
DB
DZ ZSEL=1
DZ ZSEL=1
DZ ZSEL=0
DZ ZSEL=0
Max
Max
SEIKO NPC CORPORATION - 7
SM3471AB
TYPICAL APPLICATION CIRCUITS
Typical Application Circuit 1
A/B/Z-phase differential input
5V
1uF
0.01uF
VDD
DA
A(cos)
DB
A
AN(-cos)
AN
SM3471
B(sin)
DZ
B
BN(-sin)
BN
Z
SEL0
SEL1
Interpolation
setting
ZSEL
DZ output
timing setting
Z
ZN
ZN
VREF
VSS
VSS
VSS
Typical Application Circuit 2
A/B/Z-phase single-ended input (offset voltage=VDD/2)
5V
1uF
0.01uF
VDD
DA
A(cos)
DB
A
AN
B(sin)
SM3471
BN
Z
DZ
B
SEL0
SEL1
Interpolation
setting
ZSEL
DZ output
timing setting
Z
ZN
VDD/2
=2.5V
VREF
VSS
VSS
VSS
0.01uF
SEIKO NPC CORPORATION - 8
SM3471AB
Please pay your attention to the following points at time of using the products shown in this document.
1. The products shown in this document (hereinafter ”Products”) are designed and manufactured to the generally accepted standards of
reliability as expected for use in general electronic and electrical equipment, such as personal equipment, machine tools and
measurement equipment. The Products are not designed and manufactured to be used in any other special equipment requiring
extremely high level of reliability and safety, such as aerospace equipment, nuclear power control equipment, medical equipment,
transportation equipment, disaster prevention equipment, security equipment. The Products are not designed and manufactured to be
used for the apparatus that exerts harmful influence on the human lives due to the defects, failure or malfunction of the Products.
If you wish to use the Products in that apparatus, please contact our sales section in advance.
In the event that the Products are used in such apparatus without our prior approval, we assume no responsibility whatsoever for any
damages resulting from the use of that apparatus.
2. NPC reserves the right to change the specifications of the Products in order to improve the characteristics or reliability thereof.
3. The information described in this document is presented only as a guide for using the Products. No responsibility is assumed by us for any
infringements of patents or other rights of the third parties which may result from its use. No license is granted by implication or otherwise
under any patents or other rights of the third parties. Then, we assume no responsibility whatsoever for any damages resulting from that
infringements.
4. The constant of each circuit shown in this document is described as an example, and it is not guaranteed about its value of the mass
production products.
5. In the case of that the Products in this document falls under the foreign exchange and foreign trade control law or other applicable laws and
regulations, approval of the export to be based on those laws and regulations are necessary. Customers are requested appropriately take
steps to obtain required permissions or approvals from appropriate government agencies.
SEIKO NPC CORPORATION
1-9-9, Hatchobori, Chuo-ku,
Tokyo 104-0032, Japan
Telephone: +81-3-5541-6501
Facsimile: +81-3-5541-6510
http://www.npc.co.jp/
Email:sales@npc.co.jp
ND15011-E-00 2015.08
SEIKO NPC CORPORATION - 9