ADC0844/ADC0848
8-Bit P Compatible A/D Converters with Multiplexer
Options
General Description
The ADC0844 and ADC0848 are CMOS 8-bit successive ap-
proximation A/D converters with versatile analog input multi-
plexers. The 4-channel or 8-channel multiplexers can be
software
configured
for
single-ended,
differential
or
pseudo-differential modes of operation.
The differential mode provides low frequency input common
mode rejection and allows offsetting the analog range of the
converter. In addition, the A/D's reference can be adjusted
enabling the conversion of reduced analog ranges with 8-bit
resolution.
The A/Ds are designed to operate from the control bus of a
wide variety of microprocessors. TRI-STATE
output latches
that directly drive the data bus permit the A/Ds to be config-
ured as memory locations or I/O devices to the microproces-
sor with no interface logic necessary.
Features
n
Easy interface to all microprocessors
n
Operates ratiometrically or with 5 V
DC
voltage reference
n
No zero or full-scale adjust required
n
4-channel or 8-channel multiplexer with address logic
n
Internal clock
n
0V to 5V input range with single 5V power supply
n
0.3" standard width 20-pin or 24-pin DIP
n
28 Pin Molded Chip Carrier Package
Key Specifications
n
Resolution
8 Bits
n
Total Unadjusted Error
1
/
2
LSB and
1 LSB
n
Single Supply
5 V
DC
n
Low Power
15 mW
n
Conversion Time
40 s
Block and Connection Diagrams
TRI-STATE
is a registered trademark of National Semiconductor Corp.
DS005016-1
*ADC0848 shown in DIP Package CH5-CH8 not included on the ADC0844
June 1999
ADC0844/ADC0848
8-Bit
P
Compatible
A/D
Converters
with
Multiplexer
Options
1999 National Semiconductor Corporation
DS005016
www.national.com
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
CC
)
6.5V
Voltage
Logic Control Inputs
-0.3V to +15V
At Other Inputs and Outputs
-0.3V to V
CC
+0.3V
Input Current at Any Pin (Note 3)
5 mA
Package Input Current (Note 3)
20 mA
Storage Temperature
-65C to +150C
Package Dissipation at T
A
=25C
875 mW
ESD Susceptibility (Note 4)
800V
Lead Temperature
(Soldering, 10 seconds)
Dual-In-Line Package (Plastic)
260C
Dual-In-Line Package (Ceramic)
300C
Molded Chip Carrier Package
Vapor Phase (60 seconds)
215C
Infrared (15 seconds)
220C
Operating Conditions
(Notes 1, 2)
Supply Voltage (V
CC
)
4.5 V
DC
to 6.0 V
DC
Temperature Range
T
MIN
T
A
T
MAX
ADC0844CCN, ADC0848BCN,
0C
T
A
70C
ADC0848CCN
ADC0844BCJ, ADC0844CCJ,
-40C
T
A
85C
ADC0848BCV, ADC0848CCV
Electrical Characteristics
The following specifications apply for V
CC
= 5 V
DC
unless otherwise specified.Boldface limits apply from T
MIN
to T
MAX
; all
other limits T
A
= T
j
= 25C.
Parameter
Conditions
ADC0844BCJ
ADC0844CCJ
ADC0844CCN
ADC0848BCN, ADC0848CCN
ADC0848BCV, ADC0848CCV
Limit
Units
Typ
Tested
Design
Typ
Tested
Design
(Note 5)
Limit
Limit
(Note 5)
Limit
Limit
(Note 6)
(Note 7)
(Note 6)
(Note 7)
CONVERTER AND MULTIPLEXER CHARACTERISTICS
Maximum Total
V
REF
=5.00 V
DC
Unadjusted Error
(Note 8)
ADC0844BCN, ADC0848BCN, BCV
1
/
2
1
/
2
LSB
ADC0844CCN, ADC0848CCN, CCV
1
1
LSB
ADC0844CCJ
1
LSB
Minimum Reference
2.4
1.1
2.4
1.2
1.1
k
Input Resistance
Maximum Reference
2.4
5.9
2.4
5.4
5.9
k
Input Resistance
Maximum Common-Mode
(Note 9)
V
CC
+0.05
V
CC
+0.05
V
CC
+0.05
V
Input Voltage
Minimum Common-Mode
(Note 9)
GND-0.05
GND-0.05
GND-0.05
V
Input Voltage
DC Common-Mode Error
Differential Mode
1/16
1
/
4
1/16
1
/
4
1
/
4
LSB
Power Supply Sensitivity
V
CC
=5V
5%
1/16
1
/
8
1/16
1
/
8
1
/
8
LSB
Off Channel Leakage
(Note 10)
Current
On Channel=5V,
-1
-0.1
-1
A
Off Channel=0V
On Channel=0V,
1
0.1
1
A
Off Channel=5V
DIGITAL AND DC CHARACTERISTICS
V
IN(1)
, Logical "1" Input
V
CC
=5.25V
2.0
2.0
2.0
V
Voltage (Min)
V
IN(0)
, Logical "0" Input
V
CC
=4.75V
0.8
0.8
0.8
V
Voltage (Max)
I
IN(1)
, Logical "1" Input
V
IN
=5.0V
0.005
1
0.005
1
A
Current (Max)
I
IN(0)
, Logical "0" Input
Current (Max)
V
IN
=0V
-0.005
-1
-0.005
-1
A
V
OUT(1)
, Logical "1"
V
CC
=4.75V
Output Voltage (Min)
I
OUT
=-360 A
2.4
2.8
2.4
V
I
OUT
=-10 A
4.5
4.6
4.5
V
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3
Electrical Characteristics
(Continued)
The following specifications apply for V
CC
= 5 V
DC
unless otherwise specified.Boldface limits apply from T
MIN
to T
MAX
; all
other limits T
A
= T
j
= 25C.
Parameter
Conditions
ADC0844BCJ
ADC0844CCJ
ADC0844CCN
ADC0848BCN, ADC0848CCN
ADC0848BCV, ADC0848CCV
Limit
Units
Typ
Tested
Design
Typ
Tested
Design
(Note 5)
Limit
Limit
(Note 5)
Limit
Limit
(Note 6)
(Note 7)
(Note 6)
(Note 7)
DIGITAL AND DC CHARACTERISTICS
V
OUT(0)
, Logical "0"
V
CC
=4.75V
0.4
0.34
0.4
V
Output Voltage (Max)
I
OUT
=1.6 mA
I
OUT
, TRI-STATE Output
V
OUT
=0V
-0.01
-3
-0.01
-0.3
-3
A
Current (Max)
V
OUT
=5V
0.01
3
0.01
0.3
3
A
I
SOURCE
, Output Source
V
OUT
=0V
-14
-6.5
-14
-7.5
-6.5
mA
Current (Min)
I
SINK
, Output Sink
V
OUT
=V
CC
16
8.0
16
9.0
8.0
mA
Current (Min)
I
CC
, Supply Current (Max)
CS =1, V
REF
Open
1
2.5
1
2.3
2.5
mA
AC Electrical Characteristics
The following specifications apply for V
CC
= 5V
DC
, t
r
= t
f
= 10 ns unless otherwise specified. Boldface limits apply from T
MIN
to T
MAX
; all other limits T
A
= T
j
= 25C.
Tested
Design
Parameter
Conditions
Typ
Limit
Limit
Units
(Note 5)
(Note 6)
(Note 7)
t
C
, Maximum Conversion Time (See Graph)
30
40
60
s
t
W(WR)
, Minimum WR Pulse Width
(Note 11)
50
150
ns
t
ACC
, Maximum Access Time (Delay from Falling Edge of
C
L
= 100 pF
145
225
ns
RD to Output Data Valid)
(Note 11)
t
1H
, t
0H
, TRI-STATE Control (Maximum Delay from Rising
C
L
= 10 pF, R
L
= 10k
125
200
ns
Edge of RD to Hi-Z State)
(Note 11)
t
WI
, t
RI
, Maximum Delay from Falling Edge of WR or RD to
(Note 11)
200
400
ns
Reset of INTR
t
DS
, Minimum Data Set-Up Time
(Note 11)
50
100
ns
t
DH
, Minimum Data Hold Time
(Note 11)
0
50
ns
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. DC and AC electrical specifications do not apply when operating
the device beyond its specified operating conditions.
Note 2: All voltages are measured with respect to the ground pins.
Note 3: When the input voltage (V
IN
) at any pin exceeds the power supply rails (V
IN
<
V
-
or V
IN
>
V
+
) the absolute value of the 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 exceed the power supply boundaries with a 5 mA current limit to four.
Note 4: Human body model, 100 pF discharged through a 1.5 k
resistor.
Note 5: Typicals are at 25C and represent most likely parametric norm.
Note 6: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 7: Design limits are guaranteed by not 100% tested. These limits are not used to calculate outgoing quality levels.
Note 8: Total unadjusted error includes offset, full-scale, linearity, and multiplexer error.
Note 9: For V
IN
(-)
V
IN
(+) the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input, which will forward-conduct for analog input
voltages one diode drop below ground or one diode drop greater than V
CC
supply. Be careful during testing at low V
CC
levels (4.5V), as high level analog inputs (5V)
can cause this input diode to conduct, especially at elevated temperatures, and 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. To achieve an
absolute 0 V
DC
to 5 V
DC
input voltage range will therefore require a minimum supply voltage of 4.950 V
DC
over temperature variations, initial tolerance and loading.
Note 10: Off channel leakage current is measured after the channel selection.
Note 11: The temperature coefficient is 0.3%/C.
www.national.com
4
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