ADC0841
8-Bit P Compatible A/D Converter
General Description
The ADC0841 is a CMOS 8-bit successive approximation
A/D converter. Differential inputs provide low frequency input
common mode rejection and allow offsetting the analog
range of the converter. In addition, the reference input can
be adjusted enabling the conversion of reduced analog
ranges with 8-bit resolution.
The A/D is designed to operate with the control bus of a va-
riety of microprocessors. TRI-STATE
output latches that di-
rectly drive the data bus permit the A/D to be configured as
a memory location or I/O device to the microprocessor 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
Internal clock
n
0V to 5V input range with single 5V power supply
n
0.3" standard width 20-pin package
n
20 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 Corporation.
NSC800
TM
is a trademark of National Semiconductor Corporation.
DS008557-1
Dual-In-Line Package (N)
DS008557-2
(N.C.-No Connection)
Top View
Molded Chip Carrier Package (V)
DS008557-3
Top View
May 1998
ADC0841
8-Bit
P
Compatible
A/D
Converter
1999 National Semiconductor Corporation
DS008557
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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 V
CC
+0.3V
At Other Inputs and Outputs
-0.3V to V
CC
+0.3V
Input Current Per Pin (Note 3)
5 mA
Input Current Per Package (Note 3)
20 mA
Storage Temperature
-65C to +150C
Package Dissipation at T
A
=25C
875 mW
Lead Temp. (Soldering, 10 seconds)
Dual-In-Line Package (Plastic)
Molded Chip Carrier Package
Vapor Phase (60 seconds)
Infrared (15 seconds)
260C
215C
220C
ESD Susceptibility (Note 10)
800V
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
ADC0841BCN, ADC0841CCN
0C
T
A
70C
ADC0841BCV, ADC0841CCV
-40C
T
A
85C
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.
ADC0841BCN, ADC0841CCN
ADC0841BCV, ADC0841CCV
Parameter
Conditions
Typ
Tested
Design
Units
(Note 6)
Limit
Limit
(Note 7)
(Note 8)
CONVERTER AND MULTIPLEXER CHARACTERISTICS
Maximum Total
V
REF
=5.00 V
DC
Unadjusted Error
(Note 4)
ADC0841BCN, BCV
1
/
2
1
/
2
LSB
ADC0841CCN, CCV
1
1
LSB
Minimum Reference
2.4
1.2
1.1
k
Input Resistance
Maximum Reference
2.4
5.4
5.9
k
Input Resistance
Maximum Common-Mode
(Note 5)
V
CC
+0.05
V
CC
+0.05
V
Input Voltage
Minimum Common-Mode
(Note 5)
GND-0.05
GND-0.05
V
Input Voltage
DC Common-Mode Error
Differential Mode
1/16
1
/
4
1
/
4
LSB
Power Supply Sensitivity
V
CC
=5V
5%
1/16
1
/
8
1
/
8
LSB
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.
ADC0841BCN, ADC0841CCN
ADC0841BCV, ADC0841CCV
Symbol
Parameter
Conditions
Typ
Tested
Design
Units
(Note 6)
Limit
Limit
(Note 7)
(Note 8)
DIGITAL AND DC CHARACTERISTICS
V
IN(1)
Logical "1" Input
V
CC
=5.25V
2.0
2.0
V
Voltage (Min)
V
IN(0)
Logical "0" Input
V
CC
=4.75V
0.8
0.8
V
Voltage (Max)
I
IN(1)
Logical "1" Input
V
IN
=5.0V
0.005
1
A
Current (Max)
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2
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.
ADC0841BCN, ADC0841CCN
ADC0841BCV, ADC0841CCV
Symbol
Parameter
Conditions
Typ
Tested
Design
Units
(Note 6)
Limit
Limit
(Note 7)
(Note 8)
DIGITAL AND DC CHARACTERISTICS
I
IN(0)
Logical "0" Input
V
IN
=0V
-0.005
-1
A
Current (Max)
V
OUT(1)
Logical "1"
V
CC
=4.75V
Output Voltage (Min)
I
OUT
=-360 A
2.8
2.4
V
I
OUT
=-10 A
4.6
4.5
V
V
OUT(0)
Logical "0"
V
CC
=4.75V
0.34
0.4
V
Output Voltage (Max)
I
OUT
=1.6 mA
I
OUT
TRI-STATE Output
V
OUT
=0V
-0.01
-0.3
-3
A
Current (Max)
V
OUT
=5V
0.01
0.3
3
A
I
SOURCE
Output Source
V
OUT
=0V
-14
-7.5
-6.5
mA
Current (Min)
I
SINK
Output Sink
V
OUT
=V
CC
16
9.0
8.0
mA
Current (Min)
I
CC
Supply Current (Max)
CS =1, V
REF
Open
1
2.3
2.5
mA
AC 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
Symbol
Parameter
Conditions
Typ
Limit
Limit
Units
(Note 6)
(Note 7)
(Note 8)
t
C
Maximum Conversion Time (See Graph)
30
40
60
s
t
W(WR)
Minimum WR Pulse Width
(Note 9)
50
150
ns
t
ACC
Maximum Access Time (Delay from Falling Edge
C
L
= 100 pF
145
225
ns
of RD to Output Data Valid)
(Note 9)
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)
t
r
= 20 ns (Note 9)
t
WI
, t
RI
Maximum Delay from Falling Edge of WR or RD to
(Note 9)
200
400
ns
Reset of INTR
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: During over-voltage conditions (V
IN
<
0V and V
IN
>
V
CC
) the maximum input current at any one pin is
5 mA. If the current is limited to
5 mA at all the pins
no more than four pins can be in this condition in order to meet the Input Current Per Package (
20 mA) specification.
Note 4: Total unadjusted error includes offset, full-scale, and linearity.
Note 5: 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 6: Typicals are at 25C and represent most likely parametric norm.
Note 7: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 8: Design limits are guaranteed but not 100% production tested. These limits are not used to calculate outgoing quality levels.
Note 9: The temperature coefficient is 0.3%/C.
Note 10: Human body model, 100 pF discharged through 1.5 k
resistor.
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