ADC10662/ADC10664
10-Bit 360 ns A/D Converter with Input Multiplexer and
Sample/Hold
General Description
Using an innovative, patented multistep
*
conversion tech-
nique, the 10-bit ADC10662 and ADC10664 are 2- and
4-input
CMOS
analog-to-digital
converters
offering
sub-microsecond conversion times yet dissipating a maxi-
mum of only 235 mW. The ADC10662 and ADC10664 per-
form a 10-bit conversion in two lower-resolution "flashes",
thus yielding a fast A/D without the cost, power dissipation,
and other problems associated with true flash approaches.
In addition to standard static performance specifications
(Linearity, Full-Scale Error, etc.) dynamic performance (THD,
S/N) is guaranteed.
The analog input voltage to the ADC10662 and ADC10664 is
sampled and held by an internal sampling circuit. Input sig-
nals at frequencies from dc to over 250 kHz can therefore be
digitized accurately without the need for an external
sample-and-hold circuit.
The ADC10662 and ADC10664 include a "speed-up" pin.
Connecting an external resistor between this pin and ground
reduces the typical conversion time to as little as 360 ns.
For ease of interface to microprocessors, the ADC10662 and
ADC10664 have been designed to appear as a memory
location or I/O port without the need for external interface
logic.
Features
n
Built-in sample-and-hold
n
Single +5V supply
n
2- or 4-input multiplexer options
n
No external clock required
Key Specifications
n
Conversion time to 10 bits:
360 ns typical, 466 ns
max over temperature
n
Sampling Rate:
1.5 MHz (min)
n
Low power dissipation:
235 mW (max)
n
Total harmonic distortion (50 kHz):
-60 dB (max)
n
No missing codes over temperature
Applications
n
Digital signal processor front ends
n
Instrumentation
n
Disk drives
n
Mobile telecommunications
Ordering Information
ADC10662
Industrial
(-40C
T
A
+85C)
Package
ADC10662CIWM
M24B Small Outline
ADC10664
Industrial
(-40C
T
A
+85C)
Package
ADC10664CIWM
M28B Small Outline
*
U.S. Patent Number 4918449
TRI-STATE
is a registered trademark of National Semiconductor Corporation.
November 2001
ADC10662/ADC10664
10-Bit
360
ns
A/D
Converter
with
Input
Multiplexer
and
Sample/Hold
2001 National Semiconductor Corporation
DS011192
www.national.com
Simplified Block Diagram
01119209
*ADC10664 Only
Connection Diagrams
01119210
Top View
01119211
Top View
ADC10662/ADC10664
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2
Pin Descriptions
DV
CC
,
AV
CC
These are the digital and analog positive sup-
ply voltage inputs. They should always be
connected to the same voltage source, but
are brought out separately to allow for sepa-
rate bypass capacitors. Each supply pin
should be bypassed with a 0.1 F ceramic
capacitor in parallel with a 10 F tantalum
capacitor to ground.
INT
This is the active low interrupt output. INT
goes low at the end of each conversion, and
returns to a high state following the rising
edge of RD .
S /H
This is the Sample/Hold control input. When
this pin is forced low (and CS is low), it
causes the analog input signal to be sampled
and initiates a new conversion.
RD
This is the active low Read control input.
When this RD and CS are low, any data
present in the output registers will be placed
on the data bus.
CS
This is the active low Chip Select control in-
put. When low, this pin enables the RD and S
/H pins.
S0, S1
These pins select the analog input that will be
connected to the A/D during the conversion.
The input is selected based on the state of S0
and S1 when S /H makes its High-to-Low
transition (See the Timing Diagrams). The
ADC10664 includes both S0 and S1. The
ADC10662 includes just S0.
V
REF-
,
V
REF+
These are the reference voltage inputs. They
may be placed at any voltage between GND
and V
CC
, but V
REF+
must be greater than
V
REF-
. An input voltage equal to V
REF-
pro-
duces an output code of 0, and an input volt-
age equal to (V
REF+
- 1 LSB) produces an
output code of 1023.
V
IN0
, V
IN1
,
V
IN2
, V
IN3
These are the analog input pins. The
ADC10662 has two inputs (V
IN0
and V
IN1
)
and the ADC10664 has four inputs (V
IN0
,
V
IN1
, V
IN2
and V
IN3
). The impedance of the
source should be less than 500
for best
accuracy and conversion speed. For accurate
conversions, no input pin (even one that is
not selected) should be driven more than
50 mV above V
CC
or 50 mV below ground.
GND, AGND, DGND
These are the power supply ground pins. The
ADC10662 and ADC10664 have separate
analog and digital ground pins (AGND and
DGND) for separate bypassing of the analog
and digital supplies. The ground pins should
be connected to a stable, noise-free system
ground. Both pins should be returned to the
same potential.
DB0DB9
These are the TRI-STATE output pins.
SPEED
ADJ
By connecting a resistor between this pin and
ground, the conversion time can be reduced.
The specifications listed in the table of Elec-
trical Characteristics apply for a speed adjust
resistor (R
SA
) equal to 14.0 k
(Mode 1) or
8.26 k
(Mode 2). See the Typical Perfor-
mance Curves and the table of Electrical
Characteristics.
ADC10662/ADC10664
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3
Absolute Maximum Ratings
(Notes 1,
2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
+
= AV
CC
= DV
CC
)
-0.3V to +6V
Voltage at Any Input or Output
-0.3V to V
+
+ 0.3V
Input Current at Any Pin (Note 3)
5 mA
Package Input Current (Note 3)
20 mA
Power Dissipation (Note 4)
875 mW
ESD Susceptability (Note 5)
2000V
Soldering Information (Note 6)
N Package (10 Sec)
260C
SO Package:
Vapor Phase (60 Sec)
215C
Infrared (15 Sec)
220C
Storage Temperature Range
-65C to +150C
Junction Temperature
150C
Operating Ratings
(Notes 1, 2)
Temperature Range
T
MIN
T
A
T
MAX
ADC10662CIN, ADC10662CIWM,
ADC10664CIN,
ADC10664CIWM
-40C
T
A
+85C
Supply Voltage Range
4.5V to 5.5V
Converter Characteristics
The following specifications apply for V
+
= +5V, V
REF(+)
= +5V, V
REF(-)
= GND, and Speed Adjust pin connected to ground
through a 14.0 k
resistor (Mode 1) or an 8.26 k
resistor (Mode 2) unless otherwise specified. Boldface limits apply for T
A
= T
J
= T
Min
to T
Max
; all other limits T
A
= T
J
= +25C.
Symbol
Parameter
Conditions
Typical
Limit
Units
(Note 7)
(Note 8)
(Limit)
Resolution
10
Bits
Integral Linearity Error
0.5
1.0/
1.5
LSB
Offset Error
1.5
LSB (max)
Full-Scale Error
1
LSB (max)
Total Unadjusted Error
0.5
1.5/
2.2
LSB
Missing Codes
0
(max)
Power Supply Sensitivity
V
+
= 5V
5%, V
REF
= 4.5V
1/16
LSB
V
+
= 5V
10%, V
REF
= 4.5V
1
/
8
LSB
THD
Total Harmonic Distortion (Note 10)
f
IN
= 1 kHz, 4.85 V
P-P
-68
dB
f
IN
= 50 kHz, 4.85 V
P-P
-66
-60
dB (max)
f
IN
= 100 kHz, 4.85 V
P-P
-62
dB
f
IN
= 240 kHz, 4.85 V
P-P
-58
dB
SNR
Signal-to-Noise Ratio (Note 10)
f
IN
= 1 kHz, 4.85 V
P-P
61
dB
f
IN
= 50 kHz, 4.85 V
P-P
60
58
dB (min)
f
IN
= 100 kHz, 4.85 V
P-P
60
dB
ENOB
Effective Number of Bits (Note 10)
f
IN
= 1 kHz, 4.85 V
P-P
9.6
Bits
f
IN
= 50 kHz, 4.85 V
P-P
9.5
9
Bits (min)
R
REF
Reference Resistance
650
400
(min)
900
(max)
V
REF(+)
V
REF(+)
Input Voltage
V
+
+ 0.05
V (max)
V
REF(-)
V
REF(-)
Input Voltage
GND - 0.05
V (min)
V
REF(+)
V
REF(+)
Input Voltage
V
REF(-)
V (min)
V
REF(-)
V
REF(-)
Input Voltage
V
REF(+)
V (max)
V
IN
Input Voltage
V
+
+ 0.05
V (max)
V
IN
Input Voltage
GND - 0.05
V (min)
OFF Channel Input Leakage Current
CS = V
+
, V
IN
= V
+
0.01
3
A (max)
ON Channel Input Leakage Current
CS = V
+
, V
IN
= V
+
1
-3
A (max)
ADC10662/ADC10664
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4
DC Electrical Characteristics
The following specifications apply for V
+
= +5V, V
REF(+)
= 5V V
REF(-)
= GND, and Speed Adjust pin connected to ground
through a 14.0 k
resistor (Mode 1) or an 8.26 k
resistor (Mode 2) unless otherwise specified. Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= +25C.
Symbol
Parameter
Conditions
Typical
(Note 7)
Limit
(Note 8)
Units
(Limits)
V
IN(1)
Logical "1" Input Voltage
V
+
= 5.5V
2.0
V (min)
V
IN(0)
Logical "0" Input Voltage
V
+
= 4.5V
0.8
V (max)
I
IN(1)
Logical "1" Input Current
V
IN(1)
= 5V
0.005
3.0
A (max)
I
IN(0)
Logical "0" Input Current
V
IN(0)
0V
-0.005
-3.0
A (max)
V
OUT(1)
Logical "1" Output Voltage
V
+
= 4.5V, I
OUT
= -360 A
2.4
V (min)
V
+
= 4.5V, I
OUT
= -10 A
4.25
V (min)
V
OUT(0)
Logical "0" Output Voltage
V
+
= 4.5V, I
OUT
= 1.6 mA
0.4
V (max)
I
OUT
TRI-STATE
Output Current
V
OUT
= 5V
0.1
50
A (max)
V
OUT
= 0V
-0.1
-50
A (max)
DI
CC
DV
CC
Supply Current
CS = S /H = RD = 0
1.0
2
mA (max)
AI
CC
AV
CC
Supply Current
CS = S /H = RD = 0
30
45
mA (max)
AC Electrical Characteristics
The following specifications apply for V
+
= +5V, t
r
= t
f
= 20 ns, V
REF(+)
= 5V, V
REF(-)
= GND, and Speed Adjust pin connected
to ground through a 14.0 k
resistor (Mode 1) or an 8.26 k
resistor (Mode 2) unless otherwise specified. Boldface limits ap-
ply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= +25C.
Symbol
Parameter
Conditions
Typical
(Note 7)
Limit
(Note 8)
Units
(Limits)
t
CONV
Mode 1 Conversion Time
from Rising Edge of S /H
to Falling Edge of INT
360
466
ns (max)
t
CRD
Mode 2 Conversion Time
470
610
ns (max)
t
ACC1
Access Time (Delay from Falling
Edge of RD to Output Valid)
Mode 1; C
L
= 100 pF
30
50
ns (max)
t
ACC2
Access Time (Delay from Falling
Edge of RD to Output Valid)
Mode 2; C
L
= 100 pF
475
616
ns (max)
t
SH
Minimum Sample Time
Mode 1
(Figure 1 ) ; (Note 9)
150
ns (max)
t
1H
, t
0H
TRI-STATE Control (Delay
from Rising Edge of RD
to High-Z State)
R
L
= 1k, C
L
= 10 pF
30
60
ns (max)
t
INTH
Delay from Rising Edge of RD
to Rising Edge of INT
C
L
= 100 pF
25
50
ns (max)
t
P
Delay from End of Conversion
to Next Conversion
50
ns (max)
t
MS
Multiplexer Control Setup Time
10
75
ns (max)
t
MH
Multiplexer Hold Time
10
40
ns (max)
C
VIN
Analog Input Capacitance
35
pF (max)
C
OUT
Logic Output Capacitance
5
pF (max)
C
IN
Logic Input Capacitance
5
pF (max)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional. These ratings do not guarantee specific performance limits, however. For guaranteed specifications and test conditions, see the Electrical Characteristics.
The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the
listed test conditons.
Note 2: All voltages are measured with respect to GND, unless otherwise specified.
Note 3: When the input voltage (V
IN
) at any pin exceeds the power supply rails (V
IN
<
GND or V
IN
>
V
+
) the absolute value of current at that pin should be limited
to 5 mA or less. The 20 mA package input current limits the number of pins that can safely exceed the power supplies with an input current of 5 mA to four.
Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
JMAX
,
JA
and the ambient temperature, T
A
. The maximum
allowable power dissipation at any temperature is P
D
= (T
JMAX
- T
A
)/
JA
or the number given in the Absolute Maximum Ratings, whichever is lower. In most cases,
the maximum derated power dissipation will be reached only during fault conditions. For these devices, T
JMAX
for a board-mounted device can be found from the
tables below:
ADC10662/ADC10664
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5
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