®
®
ADS-930
16-Bit, 500kHz
Sampling A/D Converters
INNOVATION and EXCELLENCE
FEATURES
•
•
•
•
•
•
•
•
•
16-bit resolution
500kHz sampling rate
Functionally complete
Excellent dynamic performance
83dB SNR, –89dB THD
No missing codes
Small, 40-pin, TDIP package
3.5 Watts power dissipation
On-board FIFO
PIN
INPUT/OUTPUT CONNECTIONS
FUNCTION
+10V REF. OUT
BIPOLAR
ANALOG INPUT
ANALOG GROUND
OFFSET ADJUST
GAIN ADJUST
+15V SUPPLY
COMP. BITS
ENABLE
FIFO READ
ANALOG GROUND
–15V SUPPLY
ANALOG GROUND
OVERFLOW
EOC
+5V SUPPLY
START CONVERT
DIGITAL GROUND
FSTAT1
FSTAT2
PIN
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
FUNCTION
BIT 1 (MSB)
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
ANALOG GROUND
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14
DIGITAL GROUND
FIFO/DIR
BIT 15
BIT 16 (LSB)
GENERAL DESCRIPTION
The low-cost ADS-930 is a high-performance, 16-bit, 500kHz
sampling A/D converter. This device accurately samples full-
scale input signals up to Nyquist frequencies with no missing
codes. The dynamic performance of the ADS-930 is optimized
to achieve a THD of –89dB and an SNR of 83dB.
Packaged in a small, 40-pin, ceramic TDIP, the functionally
complete ADS-930 contains a fast-settling sample-hold
amplifier, a subranging (three-pass) A/D converter, an internal
reference, an on-board FIFO, timing and control logic, three-
state outputs and error-correction circuitry. Digital inputs/
outputs are TTL.
Requiring ±15V and +5V supplies, the ADS-930 typically
dissipates 3.5 Watts. The unit is offered with a bipolar input
range of ±5V or a unipolar input range of 0 to –10V. Models
are available for use in either commercial (0 to +70°C) or
military (–55 to +125°C) operating temperature ranges.
Typical applications include radar, sonar, medical/graphic
imaging, and FFT spectrum analysis.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
19 FSTAT1
20 FSTAT2
GAIN ADJUST 6
GAIN
ADJUST
CKT.
23 FIFO/DIR
10 FIFO READ
40 BIT 1 (MSB)
39 BIT 1 (MSB)
+10V REF. OUT 1
POWER AND GROUNDING
+5V SUPPLY
+15V SUPPLY
–15V SUPPLY
ANALOG GROUND
DIGITAL GROUND
16
7
12
4, 11, 13, 30
18, 24
BIPOLAR 2
OFFSET ADJUST 5
3-PASS ANALOG-TO-DIGITAL CONVERTER
PRECISION
+10V REFERENCE
38 BIT 2
37 BIT 3
36 BIT 4
CUSTOM GATE ARRAY
3-STATE
OUTPUT REGISTER
35 BIT 5
34 BIT 6
33 BIT 7
32 BIT 8
31 BIT 9
29 BIT 10
28 BIT 11
27 BIT 12
26 BIT 13
25 BIT 14
22 BIT 15
21 BIT 16 (LSB)
9 ENABLE
14 OVERFLOW
OFFSET
ADJUST
CKT.
ANALOG INPUT 3
S/H
START CONVERT 17
EOC 15
COMP. BITS 8
TIMING AND
CONTROL LOGIC
Figure 1. ADS-930 Functional Block Diagram
DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048 (U.S.A.)
•
Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356
•
Email: datellit@mcimail.com
®
®
ADS-930
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
+15V Supply
(Pin 7)
–15V Supply
(Pin 12)
+5V Supply (Pin
16)
Digital Inputs
(Pin 8, 9, 10, 17, 23)
Analog Input
(Pin 3)
Unipolar
Bipolar
Lead Temperature
(10 seconds)
LIMITS
0 to +16
0 to –16
0 to +6
–0.3 to +V
DD
+0.3
–12.5 to +12.5
–7.5 to +12.5
+300
UNITS
Volts
Volts
Volts
Volts
Volts
Volts
°C
PHYSICAL/ENVIRONMENTAL
PARAMETERS
Operating Temp. Range, Case
ADS-930MC
ADS-930MM
Thermal Impedance
θjc
θca
Storage Temperature Range
Package Type
Weight
MIN.
0
–55
—
—
–65
TYP.
—
—
MAX.
+70
+125
UNITS
°C
°C
4
—
°C/Watt
18
—
°C/Watt
—
+150
°C
40-pin, metal-sealed, ceramic TDIP
0.56 ounces (16 grams)
FUNCTIONAL SPECIFICATIONS
(T
A
= +25°C, ±V
CC
= ±15V, +V
DD
= +5V, 500kHz sampling rate, and a minimum 5 minute warmup
unless otherwise specified.)
+25°C
ANALOG INPUTS
Input Voltage Range
Bipolar
Unipolar
Input Resistance
Input Capacitance
DIGITAL INPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Start Convert Positive Pulse Width
STATIC PERFORMANCE
Resolution
Integral Nonlinearity
(f
in
= 10kHz)
Differential Nonlinearity
(f
in
= 10kHz)
Full Scale Absolute Accuracy
Unipolar Zero Error
(Tech Note 2)
Bipolar Zero Error
(Tech Note 2)
Bipolar Offset Error
(Tech Note 2)
Gain Error
(Tech Note 2)
No Missing Codes
(f
in
= 10kHz)
DYNAMIC PERFORMANCE
Peak Harmonics
(–0.5dB)
dc to 100kHz
100kHz to 250kHz
Total Harmonic Distortion
(–0.5dB)
dc to 100kHz
100kHz to 250kHz
Signal–to–Noise Ratio
(w/o distortion, –0.5dB)
dc to 100kHz
100kHz to 250kHz
Signal–to–Noise Ratio
(& distortion, –0.5dB)
dc to 100kHz
100kHz to 250kHz
Two–Tone Intermodulation
Distortion
(f
in
= 100kHz,
240kHz, f
s
= 500kHz, –0.5dB)
Noise
Input Bandwidth
(–3dB)
Small Signal (–20dB input)
Large Signal (–0.5dB input)
Feedthrough Rejection
(f
in
= 250kHz)
Slew Rate
—
—
—
—
81
—
78
—
—
—
—
—
—
—
–91
–86
–89
–84
83
80
81
78
–82
150
2
1.1
92
±80
—
—
–81
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
81
—
77
—
—
—
—
—
—
—
–91
–86
–89
–84
83
80
81
78
–82
150
2
1.1
92
±80
—
—
–81
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
75
—
72
—
—
—
—
—
—
—
–87
–84
–85
–82
80
79
78
76
–81
150
2
1.1
92
±80
—
—
–76
—
—
—
—
—
—
—
—
—
—
—
dB
dB
dB
dB
dB
dB
dB
dB
dB
µVrms
MHz
MHz
dB
V/µs
—
—
—
—
—
—
—
—
16
16
±1.0
±0.75
±0.05
±0.05
±0.05
±0.05
±0.1
—
—
—
—
±0.18
±0.085
±0.085
±0.15
±0.15
—
—
—
—
—
—
—
—
—
16
16
±1.5
±1.0
±0.2
±0.1
±0.15
±0.1
±0.15
—
—
—
—
±0.5
±0.25
±0.25
±0.25
±0.35
—
—
—
—
—
—
—
—
—
15
16
±2.0
±1.5
±0.5
±0.25
±0.25
±0.25
±0.25
—
—
—
—
±0.8
±0.5
±0.5
±0.5
±0.65
—
Bits
LSB
LSB
%FSR
%FSR
%FSR
%FSR
%
Bits
+2.0
—
—
—
175
—
—
—
—
200
—
+0.8
+20
–20
215
+2.0
—
—
—
175
—
—
—
—
200
—
+0.8
+20
–20
215
+2.0
—
—
—
175
—
—
—
—
200
—
+0.8
+20
–20
215
Volts
Volts
µA
µA
ns
MIN.
—
—
1.4
—
TYP.
±5
0 to –10
1.5
7
MAX.
—
—
1.7
15
MIN.
—
—
1.4
—
0 to +70°C
TYP.
±5
0 to –10
1.5
7
MAX.
—
—
1.7
15
MIN.
—
—
1.4
—
–55 to +125°C
TYP.
±5
0 to –10
1.5
7
MAX.
—
—
1.7
15
UNITS
Volts
Volts
kΩ
pF
2
®
®
ADS-930
+25°C
DYNAMIC PERFORMANCE
(Cont.)
Aperture Delay Time
Aperture Uncertainty
S/H Acquisition Time
( to ±0.003%FSR, 10V step)
Overvoltage Recovery Time
A/D Conversion Rate
ANALOG OUTPUT
Internal Reference
Voltage
Drift
External Current
DIGITAL OUTPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Delay, Falling Edge of ENABLE
to Output Data Valid
Output Coding
POWER REQUIREMENTS
Power Supply Ranges
+15V Supply
–15V Supply
+5V Supply
Power Supply Currents
+15V Supply
–15V Supply
+5V Supply
Power Dissipation
Power Supply Rejection
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+110
–100
+80
3.5
—
+15.5
–15.5
+5.25
+130
–125
+90
4.25
±0.02
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+110
–100
+80
3.5
—
+15.5
–15.5
+5.25
+130
–125
+90
4.25
±0.02
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+110
–100
+80
3.5
—
+15.5
–15.5
+5.75
+130
–125
+90
4.25
±0.02
Volts
Volts
Volts
mA
mA
mA
Watts
%FSR/%V
+2.4
—
—
—
—
—
—
—
—
—
+0.4
–4
+4
+2.4
—
—
—
—
—
—
—
—
+0.4
–4
+4
+2.4
—
—
—
—
—
—
—
—
+0.4
–4
+4
Volts
Volts
mA
mA
ns
+9.95
—
—
+10.0
±10
—
+10.05
—
1
+9.95
—
—
+10.0
±10
—
+10.05
—
1
+9.95
—
—
+10.0
±10
—
+10.05
—
1
Volts
ppm/°C
mA
MIN.
—
—
—
—
500
TYP.
±10
5
460
600
—
MAX.
—
—
545
1000
—
MIN.
—
—
—
—
500
0 to +70°C
TYP.
±10
5
460
600
—
MAX.
—
—
545
1000
—
MIN.
—
—
—
—
500
–55 to +125°C
TYP.
±10
5
460
600
—
MAX.
—
—
545
1000
—
UNITS
ns
ps rms
ns
ns
kHz
—
10
—
—
10
—
—
10
Complementary Offset Binary; Complementary Two's Complement, Offset Binary, Two's Complement
Footnotes:
All power supplies must be on before applying a start convert pulse. All
supplies and the clock (START CONVERT) must be present during warmup
periods. The device must be continuously converting during this time.
When COMP. BITS (pin 8) is low, logic loading "0" will be –350µA.
A 200ns wide start convert pulse is used for all production testing. For
6.02
applications requiring less than a 500kHz sampling rate, wider start convert
pulses can be used.
Effective bits is equal to:
(SNR + Distortion) – 1.76 +
20 log
Full Scale Amplitude
Actual Input Amplitude
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-930
requires careful attention to pc-card layout and power
supply decoupling. The device's analog and digital
ground systems are connected to each other internally.
For optimal performance, tie all ground pins (4, 11, 13,
18, 24 and 30) directly to a large
analog
ground plane
beneath the package.
Bypass all power supplies and the +10V reference output
to ground with 4.7µF tantalum capacitors in parallel with
0.1µF ceramic capacitors. Locate the bypass capacitors
as close to the unit as possible.
2. The ADS-930 achieves its specified accuracies without
the need for external calibration. If required, the device's
small initial offset and gain errors can be reduced to zero
using the adjustment circuitry shown in Figure 2. When
using this circuitry, or any similar offset and gain calibra-
tion hardware, make adjustments following warmup. To
avoid interaction, always adjust offset before gain. Tie
pins 5 and 6 to ANALOG GROUND (pin 4) if not using
offset and gain adjust circuits.
3. Pin 8 (COMP. BITS) is used to select the digital output coding
format of the ADS-930. See Tables 3a and 3b. When this pin
has a TTL logic "0" applied, it complements all of the
ADS-930's digital outputs.
When pin 8 has a logic "1" applied and the ADS-930 is
operated within its unipolar (0 to –10V) input range, the output
coding is straight binary. Applying a logic "0" to pin 8 under
these conditions changes the output coding to complemen-
tary binary.
When pin 8 has a logic "1" applied and the ADS-930 is
operated within its bipolar (±5V) input range, the output coding
is offset binary. Applying a logic "0" to pin 8 under these
conditions changes the coding to complementary offset
binary. Using the MSB output (pin 40) instead of the MSB
output (pin 39) under these conditions changes the respective
output codings to two's complement and complementary two's
complement.
Pin 8 is TTL-compatible and can be directly driven with digital
logic in applications requiring dynamic control over its
function. There is an internal pull-up resistor on pin 8 allowing
3
®
®
ADS-930
TECHNICAL NOTES cont.
it to be either connected to +5V or left open when a logic "1"
is required.
4. To enable the three-state outputs, connect ENABLE (pin 9)
to a logic "0" (low). To disable, connect pin 9 to a logic "1"
(high).
5. Applying a start convert pulse while a conversion is in
progress (EOC = logic "1") will initiate a new and probably
inaccurate conversion cycle.
6. Do not enable/disable or complement the output bits or
read from the FIFO during the conversion process (from the
falling edge of START CONVERT to the falling edge of
EOC).
FIFO immediately after the first conversion has been
completed and remains there until the FIFO is read.
If the output three-state register has been enabled (logic "0"
applied to pin 9), data from the first conversion will appear at
the output of the ADS-930. Attempting to write a 17th word
to a full FIFO will result in that data, and any subsequent
conversion data, being lost.
Once the FIFO is full (indicated by FSTAT1 and FSTAT2
both = "1"), it can be read by dropping the FIFO READ line
(pin 10) to a logic "0" and then applying a series of 15 rising
edges to the read line. Since the first data word is already
present at the FIFO output, the first read command (the first
rising edge applied to FIFO READ) will bring data from the
second conversion to the output. Each subsequent read
command/rising edge brings the next word to the output
lines.
If a read command is issued after the FIFO has been
emptied, the last word (the 16th conversion) will remain
present at the outputs.
FIFO Reset Feature
At any time, the FIFO can be reset to an empty state by
putting the ADS-930 into its "direct" mode (logic "0" applied
to pin 23, FIFO/DIR) and also applying a logic "0" to the
FIFO READ line (pin 10). The empty status of the FIFO will
be indicated by FSTAT1 going to a "0" and FSTAT2 going to
a "1". The status outputs will change 40ns after the control
signals have been applied.
FIFO Status, FSTAT1 and FSTAT2
The status of the data in the FIFO can be monitored by
reading the two status pins, FSTAT1 (pin 19) and FSTAT2
(pin 20).
CONTENTS
Empty (0 words)
<half full (≤7 words)
half-full or more (≥8 words)
Full (16 words)
FSTAT1
0
0
1
1
FSTAT2
1
0
0
1
INTERNAL FIFO OPERATION
The ADS-930 contains an internal, user-initiated, 18-bit, 16-
word FIFO memory. Each word in the FIFO contains the 16
data bits as well as the MSB and OVERFLOW bits. Pins 23
(FIFO/DIR) and 10 (FIFO READ) control the FIFO's operation.
The FIFO's status can be monitored by reading pins 19
(FSTAT1) and 20 (FSTAT2).
When pin 23 (FIFO/DIR) has a logic "1" applied, the FIFO is
inserted into the digital data path. When pin 23 has a logic "0"
applied, the FIFO is transparent, and the output data goes
directly to the output three-state register (whose operation is
controlled by pin 9 (ENABLE)). Read and write commands to
the FIFO are ignored when the ADS-930 is operated in the
"direct" mode. It takes a maximum of 20ns to switch the FIFO
in or out of the ADS-930's operation.
FIFO WRITE and READ Modes
Once the FIFO has been enabled (pin 23 high), digital data is
automatically written to it, regardless of the status of FIFO
READ (pin 10). Assuming the FIFO is initially empty, it will
accept data (18-bit words) from the next 16 consecutive A/D
conversions. As a precaution, pin 10 (which controls the
FIFO's READ function) should not be low when data is first
written to an empty FIFO.
When the FIFO is initially empty, digital data from the first
conversion (the "oldest" data) appears at the output of the
Table 1. FIFO Delays
DELAY
Direct mode to FIFO enabled
FIFO enabled to direct mode
FIFO READ to output data valid
FIFO READ to status update when changing
from <half full (1 word) to empty
FIFO READ to status update when changing
from
≥half
full (8 words) to <half full (7 words)
FIFO READ to status update when changing
from full (16 words) to
≥half
full (15 words)
Falling edge of EOC to status update when writing
first word into empty FIFO
Falling edge of EOC to status update when
changing FIFO from <half full (7 words) to
≥half
full (8 words)
Falling edge of EOC to status update when filling
FIFO with 16th word
PIN
23
23
10
10
10
10
15
15
15
TRANSITION
0
1
0
1
1
0
1
0
1
1
MIN.
–
–
–
–
–
–
–
–
–
TYP.
10
10
–
–
–
–
–
–
–
MAX.
20
20
40
28
110
190
190
110
28
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
0
0
1
1
1
0
0
0
4
®
®
ADS-930
CALIBRATION PROCEDURE
(Refer to Figure 2 and Tables 3a, and 3b)
Connect the converter per Table 2 for the appropriate input
voltage range. Any offset/gain calibration procedures should
not be implemented until the device is fully warmed up. To
avoid interaction, adjust offset before gain. The ranges of
adjustment for the circuits in Figure 2 are guaranteed to
compensate for the ADS-930's initial accuracy errors and may
not be able to compensate for additional system errors.
A/D converters are calibrated by positioning their digital
outputs exactly on the transition point between two adjacent
digital output codes. This is accomplished by connecting
LED's to the digital outputs and performing adjustments until
certain LED's "flicker" equally between on and off. Other
approaches employ digital comparators or microcontrollers to
detect when the outputs change from one code to the next.
For the ADS-930, offset adjusting is normally accomplished
when the analog input is 0 minus ½ LSB (–76µV). See Table
3b for the proper bipolar and unipolar output coding.
Gain adjusting is accomplished when the analog input is at
nominal full scale minus 1½ LSB's (–9.999771V for unipolar
and +4.999771V for bipolar).
Note: Connect pin 5 to ANALOG GROUND (pin 4) for
operation without zero/offset adjustment. Connect
pin 6 to pin 4 for operation without gain adjustment.
Zero/Offset Adjust Procedure
1. Apply a train of pulses to the START CONVERT input
(pin 17) so that the converter is continuously converting.
2. For unipolar or bipolar zero/offset adjust, apply –76.3µV to
the ANALOG INPUT (pin 3).
3. For a bipolar input - adjust the offset potentiometer until the
code flickers between 1000 0000 0000 0000 and 0111
1111 1111 1111 with pin 8 tied high (offset binary) or
between 0111 1111 1111 1111 and 1000 0000 0000 0000
with pin 8 tied low (complementary offset binary).
For a unipolar input - adjust the offset potentiometer until all
output bits are 0's and the LSB flickers between 0 and 1
with pin 8 tied high (straight binary) or until all output bits
are 1's and the LSB flickers between 0 and 1 with pin 8 tied
low (complementary binary).
4. Two's complement coding requires using BIT 1 (MSB) (pin
40). With pin 8 tied high, adjust the trimpot until the output
code flickers between all 0's and all 1's.
INPUT RANGE
0 to –10V
±5V
Table 2. Input Connections
+15V
20k
Ω
–15V
+15V
20k
Ω
–15V
6
GAIN
ADJUST
+5V
4.7µF
0.1µF
DIGITAL
18, 24 GROUND
+5V
16 DIGITAL
5
OFFSET
ADJUST
+
+15V
4.7µF
4.7µF
–15V
7 +15V
0.1µF
4, 11 ANALOG
13, 30 GROUND
0.1µF
12 –15V
ADS-930
9 ENABLE
23 FIFO/DIR
19 FSTAT1
ANALOG INPUT
20 FSTAT2
FIFO READ 10
2 BIPOLAR
1 +10V REF. OUT
0.1µF
4.7µF
START CONVERT 17
COMP. BITS
8
3
15
14
40
39
38
37
36
35
34
33
32
31
29
28
27
26
25
22
21
EOC
OVERFLOW
BIT 1 (MSB)
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14
BIT 15
BIT 16 (LSB)
+
+5V
Figure 2. Bipolar Connection Diagram
INPUT PIN
Pin 3
Pin 3
TIE TOGETHER
Pins 2 and 4
Pins 1 and 2
Table 3a. Setting Output Coding Selection (Pin 8)
OUTPUT FORMAT
Straight Binary
Complementary Binary
Complementary Offset Binary
Offset Binary
Complementary Two’s Complement
(Using MSB, pin 40)
Two’s Complement
(Using MSB, pin 40)
PIN 8 LOGIC LEVEL
1
0
0
1
0
1
Table 3b. Output Coding
STRAIGHT BIN
UNIPOLAR
SCALE
–FS +1 LSB
–FS +1 1/2 LSB
–7/8 FS
–3/4 FS
–1/2FS
–1/2FS –1/2LSB
–1/4FS
–1/8FS
–1 LSB
–1/2LSB
0
INPUT
RANGE
0 to –10V
–9.999847
–9.999771
–8.750000
–7.500000
–5.000000
–4.999924
–2.500000
–1.250000
–0.000153
–0.000076
0.000000
COMP. BINARY
OUTPUT CODING
MSB
1111 1111 1111
LSB "1" to "0"
1110 0000 0000
1100 0000 0000
1000 0000 0000
0111 1111 1111
0100 0000 0000
0010 0000 0000
0000 0000 0000
LSB "0" to "1"
0000 0000 0000
LSB
1111
0000
0000
0000
1111
0000
0000
0001
0000
MSB
LSB
MSB
LSB
MSB
1000 0000 0000
LSB "0" to "1"
1001 1111 1111
1011 1111 1111
1111 1111 1111
0000 0000 0000
0011 1111 1111
0101 1111 1111
0111 1111 1111
LSB "1" to "0"
TWO'S COMP.
LSB
0000
1111
1111
1111
0000
1111
1111
1110
INPUT
RANGE
±5V
+4.999847
+4.999771
+3.750000
+2.500000
0.000000
–0.000076
–2.500000
–3.750000
–4.999847
–4.999924
–5.000000
BIPOLAR
SCALE
+FS –1 LSB
+FS –1 1/2 LSB
+3/4 FS
+1/2 FS
0
–1/2 LSB
–1/2 FS
–3/4 FS
–FS +1 LSB
–FS + 1/2 LSB
–FS
0000 0000 0000 0000
LSB "0" to "1"
0001 1111 1111 1111
0011 1111 1111 1111
0111 1111 1111 1111
1000 0000 0000 0000
1011 1111 1111 1111
1101 1111 1111 1111
1111 1111 1111 1110
LSB "1" to "0"
1111 1111 1111 1111
OFFSET BINARY
0111 1111 1111 1111
LSB "1" to "0"
0110 0000 0000 0000
0100 0000 0000 0000
0000 0000 0000 0000
1111 1111 1111 1111
1100 0000 0000 0000
1010 0000 0000 0000
1000 0000 0000 0001
LSB "0" to "1"
1000 0000 0000 0000
COMP. TWO'S COMP.
01111111 1111 1111
COMP. OFF. BIN.
5
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