ADC08031/ADC08032/ADC08034/ADC08038
8-Bit High-Speed Serial I/O A/D Converters with
Multiplexer Options, Voltage Reference, and Track/Hold
Function
General Description
The ADC08031/ADC08032/ADC08034/ADC08038 are 8-bit
successive approximation A/D converters with serial I/O and
configurable input multiplexers with up to 8 channels. The
serial I/O is configured to comply with the NSC MICROW-
IRE
TM
serial data exchange standard for easy interface to the
COPS
TM
family of controllers, and can easily interface with
standard shift registers or microprocessors.
The ADC08034 and ADC08038 provide a 2.6V band-gap de-
rived reference. For devices offering guaranteed voltage ref-
erence performance over temperature see ADC08131,
ADC08134 and ADC08138.
A track/hold function allows the analog voltage at the positive
input to vary during the actual A/D conversion.
The analog inputs can be configured to operate in various
combinations
of
single-ended,
differential,
or
pseudo-differential modes. In addition, input voltage spans
as small as 1V can be accommodated.
Applications
n
Digitizing automotive sensors
n
Process control monitoring
n
Remote sensing in noisy environments
n
Instrumentation
n
Test systems
n
Embedded diagnostics
Features
n
Serial digital data link requires few I/O pins
n
Analog input track/hold function
n
2-, 4-, or 8-channel input multiplexer options with
address logic
n
0V to 5V analog input range with single 5V power
supply
n
No zero or full scale adjustment required
n
TTL/CMOS input/output compatible
n
On chip 2.6V band-gap reference
n
0.3" standard width 8-, 14-, or 20-pin DIP package
n
14-, 20-pin small-outline packages
Key Specifications
n
Resolution:
8 bits
n
Conversion time (f
C
= 1 MHz):
8s (max)
n
Power dissipation:
20mW (max)
n
Single supply:
5V
DC
(
5%)
n
Total unadjusted error:
1
/
2
LSB and
1LSB
n
No missing codes over temperature
Ordering Information
Industrial (-40C
T
A
+85C)
Package
ADC08031CIN*
N08E
ADC08038CIN*
N20A
ADC08031CIWM,
ADC08032CIWM,
M14B
ADC08034CIWM
ADC08038CIWM
M20B
*
Not recomended for new designs.
COPS
TM
microcontrollers and MICROWIRE
TM
are trademarks of National Semiconductor Corporation.
June 2000
ADC08031/ADC08032/ADC08034/ADC08038
8-Bit
High-Speed
Serial
I/O
A/D
Converters
with
Multiplexer
Options,
V
oltage
Reference,
and
T
rack/Hold
Function
2000 National Semiconductor Corporation
DS010555
www.national.com
Connection Diagrams
ADC08038
DS010555-2
ADC08034
DS010555-3
ADC08031
Dual-In-Line Package
DS010555-5
ADC08032
Small Outline Package
DS010555-30
ADC08031
Small Outline Package
DS010555-31
ADC08031/ADC08032/ADC08034/ADC08038
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2
Absolute Maximum Ratings
(Notes 1, 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
)
6.5V
Voltage at Inputs and Outputs
-0.3V to V
CC
+ 0.3V
Input Current at Any Pin (Note 4)
5 mA
Package Input Current (Note 4)
20 mA
Power Dissipation at T
A
= 25C
(Note 5)
800 mW
ESD Susceptibility (Note 6)
1500V
Soldering Information
N Package (10 sec.)
SO Package:
Vapor Phase (60 sec.)
Infrared (15 sec.) (Note 7)
235C
215C
220C
Storage Temperature
-65C to +150C
Operating Ratings
(Notes 2, 3)
Temperature Range
T
MIN
T
A
T
MAX
ADC08031BIN, ADC08031CIN,
-40C
T
A
+85C
ADC08032BIN, ADC08032CIN,
ADC08034BIN, ADC08034CIN,
ADC08038BIN, ADC08038CIN,
ADC08031BIWM, ADC08032BIWM,
ADC08034BIWM, ADC08038BIWM
ADC08031CIWM, ADC08032CIWM,
ADC08034CIWM, ADC08038CIWM
Supply Voltage (V
CC
)
4.5 V
DC
to 6.3 V
DC
Electrical Characteristics
The following specifications apply for V
CC
= V
REF
= +5 V
DC
, and f
CLK
= 1 MHz 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
Limits
Units
(Note 8)
(Note 9)
(Limits)
CONVERTER AND MULTIPLEXER CHARACTERISTICS
Total Unadjusted Error
(Note 10)
BIN, BIWM
1
/
2
LSB (max)
CIN, CIWM
1
LSB (max)
Differential
8
Bits (min)
Linearity
R
REF
Reference Input Resistance
(Note 11)
3.5
k
1.3
k
(min)
6.0
k
(max)
V
IN
Analog Input Voltage
(Note 12)
(V
CC
+ 0.05)
V (max)
(GND - 0.05)
V (min)
DC Common-Mode Error
1
/
4
LSB (max)
Power Supply Sensitivity
V
CC
= 5V
5%,
1
/
4
LSB (max)
V
REF
= 4.75V
On Channel Leakage
On Channel = 5V,
0.2
A (max)
Current (Note 13)
Off Channel = 0V
1
On Channel = 0V,
-0.2
A (max)
Off Channel = 5V
-1
Off Channel Leakage
On Channel = 5V,
-0.2
A (max)
Current (Note 13)
Off Channel = 0V
-1
On Channel = 0V,
0.2
A (max)
Off Channel = 5V
1
DIGITAL AND DC CHARACTERISTICS
V
IN(1)
Logical "1" Input Voltage
V
CC
= 5.25V
2.0
V (min)
V
IN(0)
Logical "0" Input Voltage
V
CC
= 4.75V
0.8
V (max)
I
IN(1)
Logical "1" Input Current
V
IN
= 5.0V
1
A (max)
I
IN(0)
Logical "0" Input Current
V
IN
= 0V
-1
A (max)
V
OUT(1)
Logical "1" Output Voltage
V
CC
= 4.75V:
I
OUT
= -360 A
2.4
V (min)
I
OUT
= -10 A
4.5
V (min)
V
OUT(0)
Logical "0" Output Voltage
V
CC
= 4.75V
0.4
V (max)
I
OUT
= 1.6 mA
ADC08031/ADC08032/ADC08034/ADC08038
www.national.com
3
Electrical Characteristics
(Continued)
The following specifications apply for V
CC
= V
REF
= +5 V
DC
, and f
CLK
= 1 MHz 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
Limits
Units
(Note 8)
(Note 9)
(Limits)
DIGITAL AND DC CHARACTERISTICS
I
OUT
TRI-STATE
Output Current
V
OUT
= 0V
-3.0
A (max)
V
OUT
= 5V
3.0
A (max)
I
SOURCE
Output Source Current
V
OUT
= 0V
-6.5
mA (min)
I
SINK
Output Sink Current
V
OUT
= V
CC
8.0
mA (min)
I
CC
Supply Current
ADC08031, ADC08034,
CS = HIGH
3.0
mA (max)
and ADC08038
ADC08032 (Note 16)
7.0
mA (max)
REFERENCE CHARACTERISTICS
V
REF
OUT
Nominal Reference Output
V
REF
OUT Option
Available Only on
2.6
V
ADC08034 and
ADC08038
Electrical Characteristics
The following specifications apply for V
CC
= V
REF
= +5 V
DC
, and t
r
= t
f
= 20 ns 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
Limits
Units
(Note 8)
(Note 9)
(Limits)
f
CLK
Clock Frequency
10
kHz (min)
1
MHz (max)
Clock Duty Cycle
40
% (min)
(Note 14)
60
% (max)
T
C
Conversion Time (Not Including
f
CLK
= 1 MHz
8
1/f
CLK
(max)
MUX Addressing Time)
8
s (max)
t
CA
Acquisition Time
1
/
2
1/f
CLK
(max)
t
SELECT
CLK High while CS is High
50
ns
t
SET-UP
CS Falling Edge or Data Input
25
ns (min)
Valid to CLK Rising Edge
t
HOLD
Data Input Valid after CLK
20
ns (min)
Rising Edge
t
pd1
, t
pd0
CLK Falling Edge to Output
C
L
= 100 pF:
Data Valid (Note 15)
Data MSB First
250
ns (max)
Data LSB First
200
ns (max)
t
1H
, t
0H
TRI-STATE Delay from Rising Edge
C
L
= 10 pF, R
L
= 10 k
50
ns
of CS to Data Output and SARS Hi-Z
(see TRI-STATE Test Circuits)
C
L
= 100 pF, R
L
= 2 k
180
ns (max)
C
IN
Capacitance of Logic Inputs
5
pF
C
OUT
Capacitance of Logic Outputs
5
pF
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.
Note 2: Operating Ratings indicate conditions for which the device is functional. These ratings do not guarantee specific performance limits. For guaranteed speci-
fications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance character-
istics may degrade when the device is not operated under the listed test conditions.
Note 3: All voltages are measured with respect to AGND = DGND = 0 V
DC
, unless otherwise specified.
Note 4: When the input voltage V
IN
at any pin exceeds the power supplies (V
IN
<
(AGND or DGND) or V
IN
>
V
CC
) the current at that pin should be limited to 5 mA.
The 20 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5 mA to four pins.
Note 5: 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. For these de-
ADC08031/ADC08032/ADC08034/ADC08038
www.national.com
4
Electrical Characteristics
(Continued)
vices, T
JMAX
= 125C. The typical thermal resistances (
JA
) of these parts when board mounted follow: ADC08031 and ADC08032 with BIN and CIN suffixes
120C/W, ADC08038 with CIN suffix 80C/W. ADC08031 with CIWM suffix 140C/W, ADC08032 140C/W, ADC08034 140C/W, ADC08038 with CIWM suffix 91C/W.
Note 6: Human body model, 100 pF capacitor discharged through a 1.5 k
resistor.
Note 7: See AN450 "Surface Mounting Methods and Their Effect on Product Reliability" or Linear Data Book section "Surface Mount" for other methods of soldering
surface mount devices.
Note 8: Typicals are at T
J
= 25C and represent the most likely parametric norm.
Note 9: Guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 10: Total unadjusted error includes offset, full-scale, linearity, multiplexer.
Note 11: Cannot be tested for the ADC08032.
Note 12: For V
IN(-)
V
IN(+)
the digital code will be 0000 0000. Two on-chip diodes are tied to each analog input (see Block Diagram) which will forward-conduct for
analog input voltages one diode drop below ground or one diode drop greater than V
CC
supply. During testing at low V
CC
levels (e.g., 4.5V), high level analog inputs
(e.g., 5V) can cause an input diode to conduct, especially at elevated temperatures, which will cause errors for analog inputs near full-scale. The spec allows 50 mV
forward bias of either diode; this means that as long as the analog V
IN
does not exceed the supply voltage by more than 50 mV, the output code will be correct. Ex-
ceeding this range on an unselected channel will corrupt the reading of a selected channel. Achievement of an absolute 0 V
DC
to 5 V
DC
input voltage range will there-
fore require a minimum supply voltage of 4.950 V
DC
over temperature variations, initial tolerance and loading.
Note 13: Channel leakage current is measured after a single-ended channel is selected and the clock is turned off. For off channel leakage current the following two
cases are considered: one, with the selected channel tied high (5 V
DC
) and the remaining seven off channels tied low (0 V
DC
), total current flow through the off chan-
nels is measured; two, with the selected channel tied low and the off channels tied high, total current flow through the off channels is again measured. The two cases
considered for determining on channel leakage current are the same except total current flow through the selected channel is measured.
Note 14: A 40% to 60% duty cycle range insures proper operation at all clock frequencies. In the case that an available clock has a duty cycle outside of these limits
the minimum time the clock is high or low must be at least 450 ns. The maximum time the clock can be high or low is 100 s.
Note 15: Since data, MSB first, is the output of the comparator used in the successive approximation loop, an additional delay is built in (see Block Diagram) to allow
for comparator response time.
Note 16: For the ADC08032 V
REF
IN is internally tied to V
CC
, therefore, for the ADC08032 reference current is included in the supply current.
Typical Performance Characteristics
Linearity Error vs
Reference Voltage
DS010555-32
Linearity Error vs
Temperature
DS010555-33
Linearity Error vs
Clock Frequency
DS010555-34
Power Supply Current vs
Temperature (ADC08038,
ADC08034, ADC08031)
DS010555-35
Note: For ADC08032 add I
REF
Output Current vs
Temperature
DS010555-36
Power Supply Current
vs Clock Frequency
DS010555-37
ADC08031/ADC08032/ADC08034/ADC08038
www.national.com
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