LSI LS7083N Quadrature clock converter Datasheet

LS7083N
LS7084N
LSI/CSI
UL
®
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
(631) 271-0400 FAX (631) 271-0405
A3800
April 2009
QUADRATURE CLOCK CONVERTER
VDD (Pin 2)
Supply Voltage positive terminal.
VSS (Pin 3)
Supply Voltage negative terminal.
A (Pin 4)
Quadrature Clock Input A. This input has a filter circuit to validate
input logic level and eliminate encoder dither.
B (Pin 5)
Quadrature Clock Input B. This input has a filter circuit identical
to input A.
Mode (Pin 6)
Mode is a 3-state input to select resolutions x1, x2 or x4. The selected resolution multiplies the input quadrature clock rate by 1, 2
and 4, respectively, in producing the outputs UPCK / DNCK and
CLK (see Figure 2).
The Mode input logic levels selects resolutions as follows:
Logic 0 = x1 Float = x2 Logic 1 = x4
7083N/84N-042109-1
V DD (+V )
2
V SS (-V )
3
A
4
RBIAS
1
V DD (+V )
2
V SS (-V )
3
A
4
LS7084N
INPUT/OUTPUT DESCRIPTION:
RBIAS (Pin 1)
Input for external component connection. A resistor connected
between this input and VSS adjusts the output clock pulse width
(Tow). For proper operation, the output clock pulse width must be
less than or equal to the A, B pulse separation (TOW ≤ TPS).
1
LSI
DESCRIPTION:
The LS7083N and LS7084N are CMOS quadrature clock converters. Quadrature clocks derived from optical or magnetic encoders, when applied to the A and B inputs of the LS7083N or
LS7084N, are converted to strings of Up Clocks and Down
Clocks ( LS7083N) or to a Clock and an Up/Down direction control (LS7084N). These outputs can be interfaced directly with
standard Up/Down counters for direction and position sensing of
the encoder.
RBIAS
LS7083N
Applications:
• Interface incremental encoders to Up / Down Counters
(See Figure 6A and Figure 6B)
• Interface rotary encoders to Digital Potentiometers
(See Figure 7)
PIN ASSIGNMENT - TOP VIEW
LSI
FEATURES:
• x1 and x4 mode selection
• Up to 16MHz output clock frequency
• Programmable output clock pulse width
• On-chip filtering of inputs for optical or
magnetic encoder applications.
• TTL and CMOS compatible I/Os
• +3V to +12V operation (VDD - VSS)
• LS7083N, LS7084N (DIP);
LS7083N-S, LS7084N-S (SOIC) - See Figure 1
8
UPCK
7
DNCK
6
MODE
5
B
8
CLK
7
UP/DN
6
MODE
5
B
FIGURE 1
LS7083N - DNCK (Pin 7)
In LS7083N, this is the DOWN Clock Output. This output consists of
low-going pulses generated when A input lags the B input.
LS7084N - UP/DN (Pin 7)
In LS7084N, this is the count direction indication output. When A
input leads the B input, the UP/DN output goes high indicating that
the count direction is UP. When A input lags the B input, UP/DN
output goes low, indicating that the count direction is DOWN.
LS7083N - UPCK (Pin 8)
In LS7083N, this is the UP Clock output. This output consists of
low-going pulses generated when A input leads the B input.
LS7084N - CLK (Pin 8)
In LS7084N, this is the combined UP Clock and DOWN Clock output. The count direction at any instant is indicated by the UP/DN
output (Pin 7).
NOTE: For the LS7084N, the timing of CLK and UP/DN requires
that the counter interfacing with LS7084N counts on the rising edge
of the CLK pulses.
ABSOLUTE MAXIMUM RATINGS:
PARAMETER
SYMBOL
DC Supply Voltage
VDD - VSS
Voltage at any input
VIN
Operating temperature
TA
Storage temperature
TSTG
VALUE
16.0
VSS - 0.3 to VDD + 0.3
0 to +70
-55 to +150
UNITS
V
V
°C
°C
DC ELECTRICAL CHARACTERISTICS:
(All voltages referenced to VSS, TA = 0°C to 70°C.)
PARAMETER
Supply voltage
Supply current
SYMBOL
VDD
IDD
MIN
3.0
-
MAX
12.0
10.0
MODE Logic Low
A, B Logic Low
VIL
VIL
-
MODE Logic High
A, B Logic High
VIH
VIH
VDD - 0.5
2.0
3.0
6.6
ALL OUTPUTS:
Sink Current
VOL = 0.4V
IOL
IOH
Source Current
VOH = VDD - 0.5V
TRANSIENT CHARACTERISTICS:
(TA = 0°C to 70°C)
PARAMETER
A, B inputs:
Validation Delay
SYMBOL
UNITS
V
µA
0.5VDD
0.7
1.0
2.8
CONDITION
VDD = 12V, All
input frequencies = 0Hz
RBIAS = 2MΩ
V
V
V
V
VDD = 3V
VDD = 5V
VDD = 12V
-
V
V
V
V
VDD = 3V
VDD = 5V
VDD = 12V
1.3
1.9
2.9
-
mA
mA
mA
VDD = 3V
VDD = 5V
VDD = 12V
0.83
1.1
1.6
-
mA
mA
mA
VDD = 3V
VDD = 5V
VDD = 12V
MIN
MAX
UNITS
CONDITION
TvD
A, B inputs:
Pulse Width
-
250
170
71
ns
ns
ns
VDD = 3V
VDD = 5V
VDD = 12V
TPW
TVD + TOW
Infinite
ns
-
A to B or B to A
Phase Delay
TPS
TOW
Infinite
ns
-
A, B frequency
fA, B
-
1
2TPW
Hz
-
Input to Output Delay
TDS
-
280
220
120
ns
ns
ns
VDD = 3V
VDD = 5V
VDD = 12V
Includes input
validation delay
Output Clock Pulse Width
TOW
50
-
ns
See Fig. 4 & 5
7083N/84N-040609-2
FORWARD
A
REVERSE
TPW
TPS
B
TPS
TDS
UPCLK
(7083N)
2
4
1
4
2
TOW
DNCLK
(7083N)
CLK
(7084N)
2
4
1
4
2
2
4
1
4
2
2
4
1
4
2
UP/DN
(7084N)
NOTE: Output clocks labeled 1, 2 and 4 have the following interpretations.
1. Generated in x1, x2 and x4 modes.
2. Generated in x2 and x4 modes only.
3. Generated in x4 mode only.
FIGURE 2. LS7083N / LS7084N INPUT / OUTPUT TIMING
RBIAS
1
CURRENT
MIRROR
A
4
FILTER
B
5
FILTER
DUAL
ONE-SHOT
DUAL
ONE-SHOT
x4 CLOCK
CLOCK
AND
DIRECTION
DECODE
x2 CLOCK
x1 CLOCK
UP/DN
MODE
6
V DD
2
+V
VSS
3
-V
8 UPCK or CLK
MUX
7
DNCK or UP/DN
FIGURE 3. LS7083N/LS7084N BLOCK DIAGRAM
The information included herein is believed to be
accurate and reliable. However, LSI Computer Systems,
Inc. assumes no responsibilities for inaccuracies, nor for
any infringements of patent rights of others which may
result from its use.
7083N/84N-121206-3
2000
V DD = 3V
1500
V DD = 5V
30
V DD = 9V
25
V DD = 5V
1250
OUTPUT CLOCK PULSE WIDTH, Tow, ns
V DD = 3V
35
OUTPUT CLOCK PULSE WIDTH, Tow, µs
1000
V DD = 12V
750
500
250
200
100
300
400
20
V DD = 9V
15
V DD = 12V
10
5
500
2
4
6
8
Figure 5. Tow vs RBIAS, M
Figure 4. Tow vs RBIAS, k
10
12
SPDT (On - Off - On)
+V
+V
+V
V DD
MODE
ENCODER
A CLOCK
4
B CLOCK
5
A
B
1
UPCK
LS7083N
RBIAS
RB
DNCK
+V
6
2
6
V DD
8
7
5
4
6
MODE
CK-UP
A CLOCK
40193
ENCODER
CK-DN
B CLOCK
4
A
5
B
1
V SS
16
VDD
UPCK
8
15
7
10
LS7084N
8
CK
UP/DN
V SS
Vss
3
RB
V DD
4516
DNCK
RBIAS
V SS
3
2
8
FIGURE 6A. TYPICAL APPLICATION FOR LS7083N in x4 MODE
FIGURE 6B*. TYPICAL APPLICATION FOR LS7084N in x2 MODE
*See NOTE at bottom right of Page 1
+5V
A1
ROTARY
ENCODER
10k
10k
1M
1
2 VDD
B
3
A
GND
RBIAS
10k
10k
V SS
7083N/84N-042109-4
U/D
MODE
4 A
B
8
7
2
6
3
A1
B1 6
5
4
GND
W1 5
LS7084N
0.01uF
Part Number:
RE11CT-V1Y12-EF2CS
CLK
DIGITAL
POTENTIOMETER
1 CLK
V DD 8
U/D
CS
AD5220
0.01uF
FIGURE 7. Rotary Encoder Control of Digital Potentiometer
7
B1
W1
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