NSC ADC10464CIWM, ADC10462CIWM, ADC10461CIWM Datasheet
June 1999
ADC10461/ADC10462/ADC10464
10-Bit 600 ns A/D Converter with Input Multiplexer and
Sample/Hold
ADC10461/ADC10462/ADC10464 10-Bit 600 ns A/D Converter with Input Multiplexer and
Sample/Hold
General Description
Using an innovative, patented multistep*conversion technique, the 10-bit ADC10461, ADC10462, and ADC10464
CMOS analog-to-digital converters offer sub-microsecond
conversion times yet dissipate a maximum of only 235 mW.
The ADC10461, ADC10462, and ADC10464 perform 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. Dynamic performance (THD, S/N) is guaranteed. The
ADC10461 is pin-compatible with the ADC1061 but much
faster, thus providing a convenient upgrade path for the
ADC1061.
The analog input voltageto the ADC10461, ADC10462, and
ADC10464 is sampled and held by an internal sampling circuit. Input signals at frequencies from dc to over 200 kHz
can therefore be digitized accurately without the need for an
external sample-and-hold circuit.
The ADC10462 and ADC10464 include a “speed-up” pin.
Connecting an external resistor between this pin and ground
reduces the typical conversion time to as little as 350 ns with
only a small increase in linearity error.
For ease of interface to microprocessors, the ADC10461,
ADC10462, and ADC10464 have been designed to appear
as a memory location or I/O port without the need for external interface logic.
Ordering Information
Industrial Temp Range
(−40˚C ≤ T
ADC20461CIWM M20B Small Outline
ADC20462CIWM M24B Small Outline
ADC20464CIWM M28B Small Outline
≤ +85˚C)
A
Features
n Built-in sample-and-hold
n Single +5V supply
n 1, 2, or 4-input multiplexer options
n No external clock required
n Speed adjust pin for faster conversions (ADC10462 and
ADC10464)
Key Specifications
n Conversion time to 10 bits 600 ns typical
n Sampling Rate 800 kHz
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
Note:*U.S. Patent Number 4918449
Package
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation DS011108 www.national.com
Connection Diagrams
DS011108-10
Top View
Pin Descriptions
DVCC,AVCCThese are the digital and analog positive sup-
INT
S/H This is the Sample/Hold control input. When
RD
CS
S0, S1 On the multiple-input devices (ADC10462 and
V
REF−
V
REF+
ply voltage inputs. They should always be connected to the same voltage source, but are
brought out separately to allow for separate
bypass capacitors. Each supply pin should be
bypassed with a 0.1 µF ceramic capacitor in
parallel with a 10 µF tantalum capacitor to
ground.
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 .
this pin is forced low (and CS is low), it causes
the analog input signal to be sampled and initiates a new conversion.
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.
This is the active low Chip Select control input.
When low, this pin enables the RD and S /H
pins.
ADC10464), 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 ADC10464 includes both S0 and
S1. The ADC10462 includes just S0, and the
ADC10461 includes neither.
,
These are the reference voltage inputs. They
may be placed at any voltage between GND
and V
, but V
CC
V
. An input voltage equal to V
REF−
duces an output code of 0, and an input voltage equal to (V
put code of 1023.
must be greater than
REF+
− 1 LSB) produces an out-
REF+
REF−
pro-
DS011108-11
Top View
Top View
V
,
IN,VIN0
V
IN1,VIN2
V
IN3
These are the analog input pins. The
ADC10461 has one input (V
,
has two inputs (V
ADC10464 has four inputs (V
and V
). The impedance of the source
IN3
should be less than 500Ω for best accuracy
and V
IN0
and conversion speed. For accurate conversions, no input pin (even one that is not selected) should be driven more than 50 mV
GND, AGND,
DGND
above V
These are the power supply ground pins. The
ADC10461 has a single ground pin (GND),
or 50 mV below ground.
CC
and the ADC10462 and ADC10464 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. For the devices
with two ground pins, both pins should be re-
turned to the same potential.
DB0–DB9 These are the TRI-STATE output pins.
SPEED ADJ (ADC10462 and ADC10464 only). This pin is
normally left unconnected, but by connecting a
resistor between this pin and ground, the con-
version time can be reduced. See the Typical
Performance Curves and the table of Electri-
cal Characteristics.
DS011108-12
), the ADC10462
IN
), and the
IN1
IN0,VIN1,VIN2
www.national.com 2
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
Voltage at Any Input or Output −0.3V to V
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) 260˚C
SO Package:
AV
=
) −0.3V to +6V
DV
CC
CC
+
+ 0.3V
Vapor Phase (60 Sec) 215˚C
Infrared (15 Sec) 220˚C
Storage Temperature Range −65˚C to +150˚C
Junction Temperature 150˚C
Operating Ratings (Notes 1, 2)
Temperature Range T
ADC10461CIWM,
ADC10462CIWM,
ADC10464CIWM −40˚C ≤ T
Supply Voltage Range 4.5V to 5.5V
MIN
≤ TA≤ T
≤ +85˚C
A
MAX
Converter Characteristics
The following specifications apply for V
otherwise specified. Boldface limits apply for T
+
=
+5V, V
A
REF(+)
=
=
+5V, V
=
T
T
J
Min
to T
REF(−)
Max
=
GND, and Speed Adjust pin unconnected unless
; all other limits T
=
=
T
+25˚C.
A
J
Symbol Parameter Conditions Typical Limit Units
(Note 7) (Note 8) (Limit)
Resolution 10 Bits
Integral Linearity Error R
Offset Error
Full-Scale Error
Total Unadjusted Error R
SA
SA
≥ 18 kΩ
≥ 18 kΩ
±
0.5 LSB
±
1 LSB (max)
±
1 LSB (max)
±
0.5 LSB
Missing Codes 0 (max)
+
Power Supply Sensitivity V
THD Total Harmonic Distortion f
SNR Signal-to-Noise Ratio f
ENOB Effective Number of Bits f
R
R
V
V
V
V
V
V
REF
REF
REF(+)
REF(−)
REF(+)
REF(−)
IN
IN
Reference Resistance 650 400 Ω (min)
Reference Resistance 650 900 Ω (max)
V
Input Voltage V++ 0.05 V (max)
REF(+)
V
Input Voltage GND − 0.05 V (min)
REF(−)
V
Input Voltage V
REF(+)
V
Input Voltage V
REF(−)
Input Voltage V++ 0.05 V (max)
Input Voltage GND − 0.05 V (min)
OFF Channel Input Leakage Current CS=V
ON Channel Input Leakage Current CS=V
=
5V
+
=
V
5V
=
1 kHz, 4.85 V
IN
=
f
50 kHz, 4.85 V
IN
=
f
100 kHz, 4.85 V
IN
=
f
240 kHz, 4.85 V
IN
=
1 kHz, 4.85 V
IN
=
f
50 kHz, 4.85 V
IN
=
f
100 kHz, 4.85 V
IN
=
1 kHz, 4.85 V
IN
=
f
50 kHz, 4.85 V
IN
+
+
±
5%,V
±
10%,V
,V
,V
=
4.5V
REF
=
4.5V
REF
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
+
=
V
IN
+
=
V
IN
±
1/16 LSB
1
±
⁄
8
LSB
−68 dB
−66 −60 dB (max)
−62 dB
−58 dB
61 dB
60 58 dB (min)
60 dB
9.6 Bits
9.5 9 Bits (min)
REF(−)
REF(+)
V (min)
V (max)
0.01 3 µA (max)
±
1 −3 µA (max)
DC Electrical Characteristics
The following specifications apply for V
erwise specified. Boldface limits apply for T
+
=
+5V, V
=
5V V
REF(+)
=
=
T
A
to T
T
J
MIN
=
GND, and Speed Adjust pin unconnected unless oth-
REF(−)
; all other limits T
MAX
=
=
T
A
+25˚C.
J
Symbol Parameter Conditions Typical Limit Units
(Note 7) (Note 8) (Limits)
+
V
IN(1)
Logical “1” Input Voltage V
=
5.5V 2.0 V (min)
www.national.com3
DC Electrical Characteristics (Continued)
+
The following specifications apply for V
erwise specified. Boldface limits apply for T
=
+5V, V
A
Symbol Parameter Conditions Typical Limit Units
V
I
I
V
IN(1)
IN(0)
IN(0)
OUT(1)
Logical “0” Input Voltage V
Logical “1” Input Current V
Logical “0” Input Current V
Logical “1” Output Voltage V
V
V
I
OUT
OUT(0)
Logical “0” Output Voltage V
TRI-STATE®Output Current V
V
DI
CC
DVCCSupply Current CS=S/H=RD=0, R
CS=S/H=RD=0, R
AI
CC
AVCCSupply Current CS=S/H=RD=0, R
CS=S/H=RD=0, R
=
REF(+)
T
J
=
5V V
=
to T
T
MIN
=
GND, and Speed Adjust pin unconnected unless oth-
REF(−)
; all other limits T
MAX
=
=
T
J
+25˚C.
A
(Note 7) (Note 8) (Limits)
+
=
4.5V 0.8 V (max)
=
5V 0.005 3.0 µA (max)
IN(1)
0V −0.005 −3.0 µA (max)
IN(0)
+
+
+
OUT
OUT
=
=
=
4.5V, I
4.5V, I
4.5V, I
=
=
=
−360 µA 2.4 V (min)
OUT
=
−10 µA 4.25 V (min)
OUT
=
1.6 mA 0.4 V (max)
OUT
5V 0.1 50 µA (max)
0V −0.1 −50 µA (max)
=
∞
SA
=
18 kΩ
SA
=
∞
SA
=
18 kΩ
SA
1.0 2 mA (max)
1.0 mA (max)
30 45 mA (max)
30 mA (max)
AC Electrical Characteristics
The following specifications apply for V
nected unless otherwise specified. Boldface limits apply for T
+
=
+5V, t
=
=
t
20 ns, V
r
f
A
REF(+)
=
=
5V, V
=
T
T
J
MIN
REF(−)
to T
MAX
=
GND, and Speed Adjust pin uncon-
; all other limits T
=
=
T
+25˚C.
A
J
Symbol Parameter Conditions Typical Limit Units
(Note 7) (Note 8) (Limits)
t
CONV
t
CRD
Mode 1 Conversion Time CIN,
from Rising Edge of S /H
to Falling Edge of INT
CIWM Suffixes 600 750/900 ns (max)
R
SA
Mode 2 Conversion Time CIN,
=
18k 375 ns
CIWM Suffixes 850 1400 ns (max)
=
18k 530 ns
SA
=
100 pF 30 60 ns (max)
L
t
ACC1
Mode 2, R
Access Time (Delay from Falling Mode 1; C
Edge of RD to Output Valid)
t
ACC2
Access Time (Delay from Falling Mode 2; C
=
100 pF 900 t
L
+50 ns (max)
CRD
Edge of RD to Output Valid)
t
SH
t
1H,t0H
Minimum Sample Time (
TRI-STATE Control (Delay R
from Rising Edge of RD
Figure 1
) ; (Note 9) 250 ns (max)
=
L
1k, C
=
10 pF
L
30 60 ns (max)
to High-Z State)
t
t
INTH
P
Delay from Rising Edge of RD C
to Rising Edge of INT
Delay from End of Conversion 50 ns (max)
L
=
100 pF
25 50 ns (max)
to Next Conversion
t
MS
t
MH
C
VIN
C
OUT
C
IN
Note 1: Absolute Maximum Ratingsindicatelimitsbeyondwhich 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
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.
Multiplexer Control Setup Time 10 75 ns (max)
Multiplexer Hold Time 10 40 ns (max)
Analog Input Capacitance 35 pF (max)
Logic Output Capacitance 5 pF (max)
Logic Input Capacitance 5 pF (max)
) at any pin exceeds the power supply rails (V
IN
IN
<
GND or V
>
V+) the absolute value of current at that pin should be limited
IN
www.national.com 4
AC Electrical Characteristics (Continued)
Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
allowable power dissipation at any temperature is P
the maximum derated power dissipation will be reached only during fault conditions. For these devices, T
tables below:
D
=
(T
)/θJAor the number given in the Absolute Maximum Ratings, whichever is lower. In most cases,
JMAX−TA
Device θJA(˚C/W)
ADC20461CIWM 85
ADC20462CIWM 82
ADC20464CIWM 78
Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 6: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in a current National Semicon-
ductor Linear Data Book for other methods of soldering surface mount devices.
Note 7: Typicals represent most likely parametric norm.
Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 9: Accuracy may degrade if t
is shorter than the value specified. See curves of Accuracy vs tSH.
SH
, θJAand the ambient temperature, TA. The maximum
JMAX
for a board-mounted device can be found from the
JMAX
www.national.com5
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