ADC0804LCN [INTERSIL]

8-Bit, Microprocessor-Compatible, A/D Converters; 8位微处理器兼容, A / D转换器
ADC0804LCN
型号: ADC0804LCN
厂家: Intersil    Intersil
描述:

8-Bit, Microprocessor-Compatible, A/D Converters
8位微处理器兼容, A / D转换器

转换器 微处理器 光电二极管
文件: 总17页 (文件大小:572K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
ADC0803, ADC0804  
®
Data Sheet  
August 2002  
FN3094.4  
8-Bit, Microprocessor-Compatible, A/D  
Converters  
The ADC080X family are CMOS 8-Bit, successive-  
approximation A/D converters which use a modified  
potentiometric ladder and are designed to operate with the  
8080A control bus via three-state outputs. These converters  
appear to the processor as memory locations or I/O ports,  
and hence no interfacing logic is required.  
Features  
• 80C48 and 80C80/85 Bus Compatible - No Interfacing  
Logic Required  
• Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . . <100µs  
• Easy Interface to Most Microprocessors  
• Will Operate in a “Stand Alone” Mode  
• Differential Analog Voltage Inputs  
The differential analog voltage input has good common-  
mode-rejection and permits offsetting the analog zero-input-  
voltage value. In addition, the voltage reference input can be  
adjusted to allow encoding any smaller analog voltage span  
to the full 8 bits of resolution.  
• Works with Bandgap Voltage References  
• TTL Compatible Inputs and Outputs  
• On-Chip Clock Generator  
• Analog Voltage Input Range  
(Single + 5V Supply) . . . . . . . . . . . . . . . . . . . . . . 0V to 5V  
Typical Application Schematic  
• No Zero-Adjust Required  
• 80C48 and 80C80/85 Bus Compatible - No Interfacing  
Logic Required  
1
2
3
20  
19  
4
CS  
RD  
WR  
INTR  
DB  
DB  
DB  
DB  
DB  
DB  
DB  
DB  
V+  
CLK R  
CLK IN  
+5V  
150pF  
Pinout  
10K  
ADC0803, ADC0804  
(PDIP)  
5
11  
12  
13  
14  
15  
16  
17  
18  
7
6
5
4
3
2
1
0
TOP VIEW  
ANY  
µPROCESSOR  
6
7
8
9
10  
1
2
3
4
5
6
7
8
9
V+ OR V  
V
V
(+)  
(-)  
20  
CS  
RD  
IN  
IN  
REF  
DIFF  
INPUTS  
19  
18  
CLK R  
DB  
AGND  
WR  
0 (LSB)  
V
/2  
V
/2  
REF  
REF  
17 DB  
16 DB  
15 DB  
14 DB  
CLK IN  
INTR  
1
DGND  
2
V
(+)  
(-)  
IN  
3
V
IN  
4
8-BIT RESOLUTION  
OVER ANY  
13  
12  
DB  
DB  
AGND  
/2  
5
V
DESIRED  
REF  
6
ANALOG INPUT  
VOLTAGE RANGE  
DGND 10  
11 DB  
7 (MSB)  
Ordering Information  
o
PART NUMBER  
ERROR  
EXTERNAL CONDITIONS  
TEMP. RANGE ( C)  
PACKAGE  
PKG. NO  
E20.3  
1
ADC0803LCN  
± / LSB  
V
/2 Adjusted for Correct Full Scale  
REF  
0 to 70  
20 Ld PDIP  
2
Reading  
ADC0804LCN  
±1 LSB  
V
/2 = 2.500V  
REF  
(No Adjustments)  
0 to 70  
20 Ld PDIP  
E20.3  
DC  
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.  
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.  
Copyright © Intersil Americas Inc. 2002. All Rights Reserved  
1
ADC0803, ADC0804  
Functional Diagram  
2
READ  
RD  
“1” = RESET SHIFT REGISTER  
1
CS  
SET  
“0” = BUSY AND RESET STATE  
Q
RESET  
3
WR  
INPUT PROTECTION  
CLK R  
19  
FOR ALL LOGIC INPUTS  
CLK  
INPUT  
TO INTERNAL  
CIRCUITS  
CLK A  
CLKS  
G1  
RESET  
D
DFF1  
Q
CLK IN  
4
BV = 30V  
CLK  
GEN  
CLK OSC  
10  
START F/F  
DGND  
START  
CLK B  
MSB  
CONVERSION  
D
20  
9
V+  
REF  
(V  
)
LADDER  
AND  
DECODER  
SUCCESSIVE  
8-BIT  
APPROX.  
REGISTER  
AND LATCH  
SHIFT  
REGISTER  
IF RESET = “0”  
INTR F/F  
V
/2  
REF  
R
RESET  
Q
DAC  
OUT  
LSB  
AGND  
V
8
CLK A  
V+  
D
DFF2  
Q
COMP  
-
+
6
7
+
V
(+)  
(-)  
IN  
Q
5
-
XFER  
THREE-STATE  
SET  
G2  
OUTPUT LATCHES  
V
IN  
MSB  
LSB  
INTR  
CONV. COMPL.  
8 X 1/f  
11 12 13 14 15 16 17 18  
DIGITAL OUTPUTS  
THREE-STATE CONTROL  
“1” = OUTPUT ENABLE  
2
ADC0803, ADC0804  
Absolute Maximum Ratings  
Thermal Information  
o
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5V  
Thermal Resistance (Typical, Note 1)  
θ
( C/W)  
80  
JA  
+
Voltage at Any Input. . . . . . . . . . . . . . . . . . . . . . -0.3V to (V +0.3V)  
PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Maximum Junction Temperature  
o
Plastic Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150 C  
Operating Conditions  
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 C to 70 C  
o
o
Maximum Storage Temperature Range. . . . . . . . . . -65 C to 150 C  
o
o
o
Maximum Lead Temperature (Soldering, 10s). . . . . . . . . . . . .300 C  
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the  
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.  
NOTE:  
1. θ is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.  
JA  
Electrical Specifications (Notes 2, 8)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
o
CONVERTER SPECIFICATIONS V+ = 5V, T = 25 C and f  
= 640kHz, Unless Otherwise Specified  
CLK  
A
Total Unadjusted Error  
1
ADC0803  
V
V
/2 Adjusted for Correct Full Scale Reading  
/2 = 2.500V  
-
-
-
± /  
LSB  
LSB  
kΩ  
REF  
2
ADC0804  
-
±1  
REF  
V
/2 Input Resistance  
Input Resistance at Pin 9  
(Note 3)  
1.0  
1.3  
-
REF  
Analog Input Voltage Range  
DC Common-Mode Rejection  
Power Supply Sensitivity  
GND-0.05  
-
(V+) + 0.05  
1
V
1
Over Analog Input Voltage Range  
-
-
± /  
± /  
LSB  
LSB  
16  
16  
8
8
1
1
V+ = 5V ±10% Over Allowed Input Voltage  
± /  
± /  
Range  
o
o
CONVERTER SPECIFICATIONS V+ = 5V, 0 C to 70 C and f  
= 640kHz, Unless Otherwise Specified  
CLK  
Total Unadjusted Error  
1
ADC0803  
V
V
/2 Adjusted for Correct Full Scale Reading  
/2 = 2.500V  
-
-
-
± /  
LSB  
LSB  
kΩ  
REF  
2
ADC0804  
-
±1  
REF  
V
/2 Input Resistance  
Input Resistance at Pin 9  
(Note 3)  
1.0  
1.3  
-
REF  
Analog Input Voltage Range  
DC Common-Mode Rejection  
Power Supply Sensitivity  
GND-0.05  
-
(V+) + 0.05  
1
V
1
Over Analog Input Voltage Range  
-
-
± /  
± /  
LSB  
LSB  
8
4
8
1
1
V+ = 5V ±10% Over Allowed Input Voltage  
± /  
± /  
16  
Range  
o
AC TIMING SPECIFICATIONS V+ = 5V, and T = 25 C, Unless Otherwise Specified  
A
Clock Frequency, f  
V+ = 6V (Note 4)  
V+ = 5V  
100  
100  
62  
640  
640  
-
1280  
800  
73  
kHz  
kHz  
CLK  
Clock Periods per Conversion (Note 5),  
Clocks/Conv  
t
CONV  
Conversion Rate In Free-Running Mode, CR INTR tied to WR with CS = 0V, f  
= 640kHz  
-
-
-
8888  
-
Conv/s  
ns  
CLK  
Width of WR Input (Start Pulse Width),  
CS = 0V (Note 6)  
100  
t
W(WR)I  
Access Time (Delay from Falling Edge of  
RD to Output Data Valid), t  
C = 100pF (Use Bus Driver IC for Larger C  
-
-
-
-
-
135  
125  
300  
5
200  
250  
450  
-
ns  
ns  
ns  
pF  
pF  
L
L)  
ACC  
Three-State Control (Delay from Rising  
Edge of RD to Hl-Z State), t , t  
C = 10pF, R = 10K  
L
L
(See Three-State Test Circuits)  
1H 0H  
Delay from Falling Edge of WR to Reset of  
INTR, t , t  
WI RI  
Input Capacitance of Logic Control Inputs,  
C
IN  
Three-State Output Capacitance (Data  
Buffers), C  
5
-
OUT  
3
ADC0803, ADC0804  
Electrical Specifications (Notes 2, 8) (Continued)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
DC DIGITAL LEVELS AND DC SPECIFICATIONS V+ = 5V, and T  
CONTROL INPUTS (Note 7)  
to T  
, Unless Otherwise Specified  
MAX  
MIN  
Logic “1“ Input Voltage (Except Pin 4 CLK V+ = 5.25V  
2.0  
-
-
V+  
0.8  
3.5  
2.1  
V
V
V
V
IN), V  
INH  
Logic “0“ Input Voltage (Except Pin 4 CLK V+ = 4.75V  
IN), V  
-
INL  
CLK IN (Pin 4) Positive Going Threshold  
Voltage, V+  
2.7  
1.5  
0.6  
3.1  
1.8  
1.3  
CLK  
CLK IN (Pin 4) Negative Going Threshold  
Voltage, V-  
CLK  
CLK IN (Pin 4) Hysteresis, V  
2.0  
1
V
H
Logic “1” Input Current (All Inputs), I  
Logic “0” Input Current (All Inputs), I  
V
V
= 5V  
= 0V  
-
-1  
-
0.005  
-0.005  
1.3  
µΑ  
µA  
mA  
INHI  
lN  
lN  
-
INLO  
o
Supply Current (Includes Ladder Current), I+ f  
= 640kHz, T = 25 C and CS = Hl  
2.5  
CLK  
A
DATA OUTPUTS AND INTR  
Logic “0” Output Voltage, V  
Logic “1” Output Voltage, V  
l
l
= 1.6mA, V+ = 4.75V  
-
-
-
0.4  
V
OL  
O
= -360µA, V+ = 4.75V  
2.4  
-3  
-
-
V
OH  
O
Three-State Disabled Output Leakage (All  
Data Buffers), I  
V
V
V
V
= 0V  
= 5V  
-
µA  
µA  
mA  
mA  
OUT  
OUT  
OUT  
OUT  
LO  
-
-
3
-
o
Output Short Circuit Current, I  
Output Short Circuit Current, I  
NOTES:  
Short to GND, T = 25 C  
A
Short to V+, T = 25 C  
4.5  
9.0  
6
16  
SOURCE  
SINK  
o
-
A
2. All voltages are measured with respect to GND, unless otherwise specified. The separate AGND point should always be wired to the DGND,  
being careful to avoid ground loops.  
3. For V  
V  
the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input (see Block Diagram) which will  
IN(+)  
IN(-)  
forward conduct for analog input voltages one diode drop below ground or one diode drop greater than the V+ supply. Be careful, during testing  
at low V+ 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. As long as the analog V does not exceed the supply voltage by more than 50mV, the output code will  
IN  
be correct. To achieve an absolute 0V to 5V input voltage range will therefore require a minimum supply voltage of 4.950V over temperature  
variations, initial tolerance and loading.  
4. With V+ = 6V, the digital logic interfaces are no longer TTL compatible.  
5. With an asynchronous start pulse, up to 8 clock periods may be required before the internal clock phases are proper to start the conversion process.  
6. The CS input is assumed to bracket the WR strobe input so that timing is dependent on the WR pulse width. An arbitrarily wide pulse width will  
hold the converter in a reset mode and the start of conversion is initiated by the low to high transition of the WR pulse (see Timing Diagrams).  
7. CLK IN (pin 4) is the input of a Schmitt trigger circuit and is therefore specified separately.  
8. None of these A/Ds requires a zero-adjust. However, if an all zero code is desired for an analog input other than 0V, or if a narrow full scale span exists  
(for example: 0.5V to 4V full scale) the V  
input can be adjusted to achieve this. See the Zero Error description in this data sheet.  
IN(-)  
Timing Waveforms  
t = 20ns  
r
t
r
2.4V  
0.8V  
V+  
90%  
50%  
10%  
RD  
RD  
CS  
DATA  
OUTPUT  
t
1H  
90%  
V
OH  
C
L
10K  
DATA  
OUTPUTS  
GND  
FIGURE 1A. t  
1H  
FIGURE 1B. t , C = 10pF  
1H  
L
4
ADC0803, ADC0804  
Timing Waveforms (Continued)  
t = 20ns  
r
t
r
V+  
V+  
2.4V  
90%  
50%  
10%  
RD  
10K  
0.8V  
V+  
RD  
CS  
DATA  
OUTPUT  
t
0H  
C
DATA  
L
OUTPUTS  
10%  
V
OI  
FIGURE 1C. t  
FIGURE 1D. t , C = 10pF  
0H  
0H  
L
FIGURE 1. THREE-STATE CIRCUITS AND WAVEFORMS  
Typical Performance Curves  
1.8  
500  
400  
300  
200  
100  
o
o
-55 C TO 125 C  
1.7  
1.6  
1.5  
1.4  
1.3  
4.50  
4.75  
5.00  
5.25  
5.50  
0
200  
400  
600  
800  
1000  
LOAD CAPACITANCE (pF)  
V+ SUPPLY VOLTAGE (V)  
FIGURE 2. LOGIC INPUT THRESHOLD VOLTAGE vs SUPPLY  
VOLTAGE  
FIGURE 3. DELAY FROM FALLING EDGE OF RD TO OUTPUT  
DATA VALID vs LOAD CAPACITANCE  
1000  
3.5  
3.1  
R = 10K  
V
T(+)  
R = 50K  
2.7  
2.3  
1.9  
1.5  
o
o
-55 C TO 125 C  
V
T(-)  
R = 20K  
100  
10  
4.50  
4.75  
5.00  
5.25  
5.50  
100  
1000  
V+ SUPPLY VOLTAGE (V)  
CLOCK CAPACITOR (pF)  
FIGURE 4. CLK IN SCHMITT TRIP LEVELS vs SUPPLY  
VOLTAGE  
FIGURE 5. f  
vs CLOCK CAPACITOR  
CLK  
5
ADC0803, ADC0804  
Typical Performance Curves (Continued)  
16  
14  
7
6
5
4
3
2
1
0
V
= V  
IN(-)  
= 0V  
= 2mV  
IN(+)  
ASSUMES V  
OS  
V+ = 4.5V  
THIS SHOWS THE NEED  
FOR A ZERO ADJUSTMENT  
IF THE SPAN IS REDUCED  
12  
10  
8
6
V+ = 5V  
4
2
V+ = 6V  
1600 2000  
0
0
400  
800  
f
1200  
(kHz)  
0.01  
0.1  
1.0  
5
V
/2 (V)  
CLK  
REF  
FIGURE 6. FULL SCALE ERROR vs f  
FIGURE 7. EFFECT OF UNADJUSTED OFFSET ERROR  
CLK  
8
1.6  
V+ = 5V  
f
= 640kHz  
V+ = 5.5V  
CLK  
7
6
5
4
3
2
1.5  
1.4  
1.3  
1.2  
DATA OUTPUT  
BUFFERS  
I
V
SOURCE  
OUT  
= 2.4V  
V+ = 5.0V  
-I  
SINK  
1.1  
1.0  
V+ = 4.5V  
100  
V
= 0.4V  
0
OUT  
-50  
-25  
25  
50  
75  
o
100  
125  
-50  
-25  
0
25  
50  
75  
125  
o
T
AMBIENT TEMPERATURE ( C)  
A
T
AMBIENT TEMPERATURE ( C)  
A
FIGURE 8. OUTPUT CURRENT vs TEMPERATURE  
FIGURE 9. POWER SUPPLY CURRENT vs TEMPERATURE  
Timing Diagrams  
CS  
WR  
t
WI  
“BUSY”  
ACTUAL INTERNAL  
STATUS OF THE  
CONVERTER  
t
W(WR)I  
DATA IS VALID IN  
“NOT BUSY”  
OUTPUT LATCHES  
1 TO 8 x 1/f  
CLK  
INTERNAL T  
C
(LAST DATA READ)  
INTR  
INTR  
(LAST DATA NOT READ)  
ASSERTED  
1
t
VI  
/
f
CLK  
2
FIGURE 10A. START CONVERSION  
6
ADC0803, ADC0804  
Timing Diagrams (Continued)  
INTR RESET  
INTR  
t
RI  
CS  
RD  
THREE-STATE  
VALID  
VALID  
DATA  
DATA  
DATA  
(HI-Z)  
OUTPUTS  
t
ACC  
t
, t  
1H 0H  
FIGURE 10B. OUTPUT ENABLE AND RESET INTR  
+1 LSB  
1
3
5
4
1
+ / LSB  
2
D + 1  
D
5 6  
0
QUANTIZATION ERROR  
*
3 4  
1
D - 1  
- / LSB  
2
2
6
1 2  
-1 LSB  
A - 1  
A + 1  
A - 1  
ANALOG INPUT (V )  
IN  
A
A + 1  
A
ANALOG INPUT (V  
)
IN  
TRANSFER FUNCTION  
ERROR PLOT  
FIGURE 11A. ACCURACY = ±0 LSB; PERFECT A/D  
+1 LSB  
1
5
D + 1  
D
6
3
6
3
QUANTIZATION  
0
*
4
ERROR  
1
D - 1  
2
4
2
-1 LSB  
A - 1  
A + 1  
A - 1  
A
A + 1  
A
ANALOG INPUT (V  
)
ANALOG INPUT (V  
)
IN  
IN  
TRANSFER FUNCTION  
ERROR PLOT  
1
FIGURE 11B. ACCURACY = ± / LSB  
2
FIGURE 11. CLARIFYING THE ERROR SPECS OF AN A/D CONVERTER  
7
ADC0803, ADC0804  
connecting INTR to the WR input with CS = 0. To ensure start-  
Understanding A/D Error Specs  
up under all possible conditions, an external WR pulse is  
required during the first power-up cycle. A conversion-in-  
process can be interrupted by issuing a second start  
command.  
A perfect A/D transfer characteristic (staircase wave-form) is  
shown in Figure 11A. The horizontal scale is analog input  
voltage and the particular points labeled are in steps of 1  
LSB (19.53mV with 2.5V tied to the V  
/2 pin). The digital  
REF  
output codes which correspond to these inputs are shown as  
D-1, D, and D+1. For the perfect A/D, not only will center-  
value (A - 1, A, A + 1, . . .) analog inputs produce the correct  
Digital Operation  
The converter is started by having CS and WR simultaneously  
low. This sets the start flip-flop (F/F) and the resulting “1” level  
resets the 8-bit shift register, resets the Interrupt (INTR) F/F  
and inputs a “1” to the D flip-flop, DFF1, which is at the input  
end of the 8-bit shift register. Internal clock signals then  
transfer this “1” to the Q output of DFF1. The AND gate, G1,  
combines this “1” output with a clock signal to provide a reset  
signal to the start F/F. If the set signal is no longer present  
(either WR or CS is a “1”), the start F/F is reset and the 8-bit  
shift register then can have the “1” clocked in, which starts the  
conversion process. If the set signal were to still be present,  
this reset pulse would have no effect (both outputs of the start  
F/F would be at a “1” level) and the 8-bit shift register would  
continue to be held in the reset mode. This allows for  
output digital codes, but also each riser (the transitions  
1
between adjacent output codes) will be located ± / LSB  
2
away from each center-value. As shown, the risers are ideal  
and have no width. Correct digital output codes will be  
provided for a range of analog input voltages which extend  
1
± / LSB from the ideal center-values. Each tread (the range  
2
of analog input voltage which provides the same digital  
output code) is therefore 1 LSB wide.  
The error curve of Figure 11B shows the worst case transfer  
function for the ADC080X. Here the specification guarantees  
that if we apply an analog input equal to the LSB analog  
voltage center-value, the A/D will produce the correct digital  
code.  
asynchronous or wide CS and WR signals.  
After the “1” is clocked through the 8-bit shift register (which  
completes the SAR operation) it appears as the input to  
DFF2. As soon as this “1” is output from the shift register, the  
AND gate, G2, causes the new digital word to transfer to the  
Three-State output latches. When DFF2 is subsequently  
clocked, the Q output makes a high-to-low transition which  
causes the INTR F/F to set. An inverting buffer then supplies  
the INTR output signal.  
Next to each transfer function is shown the corresponding  
error plot. Notice that the error includes the quantization  
uncertainty of the A/D. For example, the error at point 1 of  
1
Figure 11A is + / LSB because the digital code appeared  
2
1
/ LSB in advance of the center-value of the tread. The  
2
error plots always have a constant negative slope and the  
abrupt upside steps are always 1 LSB in magnitude, unless  
the device has missing codes.  
When data is to be read, the combination of both CS and RD  
being low will cause the INTR F/F to be reset and the three-  
state output latches will be enabled to provide the 8-bit  
digital outputs.  
Detailed Description  
The functional diagram of the ADC080X series of A/D  
converters operates on the successive approximation  
principle (see Application Notes AN016 and AN020 for a  
more detailed description of this principle). Analog switches  
are closed sequentially by successive-approximation logic  
Digital Control Inputs  
The digital control inputs (CS, RD, and WR) meet standard  
TTL logic voltage levels. These signals are essentially  
equivalent to the standard A/D Start and Output Enable  
control signals, and are active low to allow an easy interface  
to microprocessor control busses. For non-microprocessor  
based applications, the CS input (pin 1) can be grounded and  
the standard A/D Start function obtained by an active low  
pulse at the WR input (pin 3). The Output Enable function is  
achieved by an active low pulse at the RD input (pin 2).  
until the analog differential input voltage [V  
- V ]  
lN(-)  
lN(+)  
matches a voltage derived from a tapped resistor string  
across the reference voltage. The most significant bit is  
tested first and after 8 comparisons (64 clock cycles), an 8-  
bit binary code (1111 1111 = full scale) is transferred to an  
output latch.  
The normal operation proceeds as follows. On the high-to-low  
transition of the WR input, the internal SAR latches and the  
shift-register stages are reset, and the INTR output will be set  
high. As long as the CS input and WR input remain low, the  
A/D will remain in a reset state. Conversion will start from 1 to  
8 clock periods after at least one of these inputs makes a low-  
to-high transition. After the requisite number of clock pulses to  
complete the conversion, the INTR pin will make a high-to-low  
transition. This can be used to interrupt a processor, or  
otherwise signal the availability of a new conversion. A RD  
operation (with CS low) will clear the INTR line high again.  
The device may be operated in the free-running mode by  
Analog Operation  
The analog comparisons are performed by a capacitive  
charge summing circuit. Three capacitors (with precise ratioed  
values) share a common node with the input to an auto-  
zeroed comparator. The input capacitor is switched between  
V
and V , while two ratioed reference capacitors are  
lN(-)  
lN(+)  
switched between taps on the reference voltage divider string.  
The net charge corresponds to the weighted difference  
between the input and the current total value set by the  
8
ADC0803, ADC0804  
successive approximation register. A correction is made to  
input at 5V, this DC current is at a maximum of approximately  
1
offset the comparison by / LSB (see Figure 11A).  
2
5µA. Therefore, bypass capacitors should not be used at  
the analog inputs or the V  
/2 pin for high resistance  
REF  
Analog Differential Voltage Inputs and Common-  
Mode Rejection  
sources (>1k). If input bypass capacitors are necessary for  
noise filtering and high source resistance is desirable to  
minimize capacitor size, the effects of the voltage drop across  
this input resistance, due to the average value of the input  
current, can be compensated by a full scale adjustment while  
the given source resistor and input bypass capacitor are both  
in place. This is possible because the average value of the  
input current is a precise linear function of the differential input  
voltage at a constant conversion rate.  
This A/D gains considerable applications flexibility from the  
analog differential voltage input. The V  
input (pin 7) can  
lN(-)  
be used to automatically subtract a fixed voltage value from  
the input reading (tare correction). This is also useful in 4mA  
- 20mA current loop conversion. In addition, common-mode  
noise can be reduced by use of the differential input.  
1
The time interval between sampling V  
and V  
lN(-)  
is 4 /  
IN(+)  
2
clock periods. The maximum error voltage due to this slight  
time difference between the input voltage samples is given by:  
Input Source Resistance  
Large values of source resistance where an input bypass  
capacitor is not used will not cause errors since the input  
currents settle out prior to the comparison time. If a low-  
pass filter is required in the system, use a low-value series  
resistor (1k) for a passive RC section or add an op amp  
RC active low-pass filter. For low-source-resistance  
applications (1k), a 0.1µF bypass capacitor at the inputs  
will minimize EMI due to the series lead inductance of a long  
wire. A 100series resistor can be used to isolate this  
capacitor (both the R and C are placed outside the feedback  
loop) from the output of an op amp, if used.  
4.5  
CLK  
V (MAX) = (V  
)(2πf  
) ------------  
E
PEAK  
CM  
f
where:  
V is the error voltage due to sampling delay,  
E
V
f
is the peak value of the common-mode voltage,  
PEAK  
is the common-mode frequency.  
CM  
For example, with a 60Hz common-mode frequency, f , and  
CM  
1
a 640kHz A/D clock, f  
, keeping this error to / LSB (~5mV)  
CLK  
4
would allow a common-mode voltage, V  
, given by:  
PEAK  
Stray Pickup  
V  
E(MAX)(f  
)
CLK  
The leads to the analog inputs (pins 6 and 7) should be kept  
as short as possible to minimize stray signal pickup (EMI).  
Both EMI and undesired digital-clock coupling to these inputs  
can cause system errors. The source resistance for these  
inputs should, in general, be kept below 5k. Larger values of  
source resistance can cause undesired signal pickup. Input  
bypass capacitors, placed from the analog inputs to ground,  
will eliminate this pickup but can create analog scale errors as  
these capacitors will average the transient input switching  
currents of the A/D (see Analog Input Current). This scale  
error depends on both a large source resistance and the use  
of an input bypass capacitor. This error can be compensated  
by a full scale adjustment of the A/D (see Full Scale  
V
= -------------------------------------------------- ,  
PEAK  
(2πf  
)(4.5)  
CM  
or  
3  
3
(5 × 10 )(640 × 10 )  
= --------------------------------------------------------- 1.9V .  
(6.28)(60)(4.5)  
V
PEAK  
The allowed range of analog input voltage usually places  
more severe restrictions on input common-mode voltage  
levels than this.  
An analog input voltage with a reduced span and a relatively  
large zero offset can be easily handled by making use of the  
differential input (see Reference Voltage Span Adjust).  
Analog Input Current  
Adjustment) with the source resistance and input bypass  
capacitor in place, and the desired conversion rate.  
The internal switching action causes displacement currents to  
flow at the analog inputs. The voltage on the on-chip  
capacitance to ground is switched through the analog  
differential input voltage, resulting in proportional currents  
Reference Voltage Span Adjust  
For maximum application flexibility, these A/Ds have been  
designed to accommodate a 5V, 2.5V or an adjusted voltage  
reference. This has been achieved in the design of the IC as  
shown in Figure 12.  
entering the V  
IN(+)  
input and leaving the V input. These  
IN(-)  
current transients occur at the leading edge of the internal  
clocks. They rapidly decay and do not inherently cause errors  
as the on-chip comparator is strobed at the end of the clock  
perIod.  
1
Notice that the reference voltage for the IC is either / of the  
2
voltage which is applied to the V+ supply pin, or is equal to  
Input Bypass Capacitors  
the voltage which is externally forced at the V  
/2 pin. This  
REF  
Bypass capacitors at the inputs will average these charges  
and cause a DC current to flow through the output resistances  
of the analog signal sources. This charge pumping action is  
allows for a pseudo-ratiometric voltage reference using, for  
the V+ supply, a 5V reference voltage. Alternatively, a  
voltage less than 2.5V can be applied to the V  
/2 input.  
REF  
worse for continuous conversions with the V  
at full scale. For a 640kHz clock frequency with the V  
input voltage  
IN(+)  
The internal gain to the V  
/2 input is 2 to allow this factor  
REF  
IN(+)  
of 2 reduction in the reference voltage.  
9
ADC0803, ADC0804  
Such an adjusted reference voltage can accommodate a  
5V  
(V  
)
REF  
reduced span or dynamic voltage range of the analog input  
voltage. If the analog input voltage were to range from 0.5V to  
3.5V, instead of 0V to 5V, the span would be 3V. With 0.5V  
R
applied to the V  
lN(-)  
pin to absorb the offset, the reference  
2R  
20  
6
7
1
voltage can be made equal to / of the 3V span or 1.5V. The  
V
± 10V  
V
V+  
IN  
IN(+)  
2
+
A/D now will encode the V  
lN(+)  
signal from 0.5V to 3.5V with  
10µF  
ADC0803-  
ADC0804  
the 0.5V input corresponding to zero and the 3.5V input  
corresponding to full scale. The full 8 bits of resolution are  
therefore applied over this reduced analog input voltage  
range. The requisite connections are shown in Figure 13. For  
expanded scale inputs, the circuits of Figures 14 and 15 can  
be used.  
2R  
V
IN(-)  
FIGURE 14. HANDLING ±10V ANALOG INPUT RANGE  
V+  
REF  
(V  
)
20  
5V  
(V  
)
REF  
R
R
R
20  
6
7
V
±5V  
V
V+  
IN  
IN(+)  
9
+
V
/2  
REF  
10µF  
DIGITAL  
CIRCUITS  
ADC0803-  
ADC0804  
V
IN(-)  
ANALOG  
CIRCUITS  
FIGURE 15. HANDLING ±5V ANALOG INPUT RANGE  
R
DECODE  
Reference Accuracy Requirements  
The converter can be operated in a pseudo-ratiometric mode  
or an absolute mode. In ratiometric converter applications,  
the magnitude of the reference voltage is a factor in both the  
output of the source transducer and the output of the A/D  
converter and therefore cancels out in the final digital output  
code. In absolute conversion applicatIons, both the initial  
value and the temperature stability of the reference voltage  
are important accuracy factors in the operation of the A/D  
8
10  
AGND  
DGND  
converter. For V  
/2 voltages of 2.5V nominal value, initial  
REF  
FIGURE 12. THE V  
DESIGN ON THE IC  
REFERENCE  
5V  
errors of ±10mV will cause conversion errors of ±1 LSB due  
to the gain of 2 of the V /2 input. In reduced span  
REF  
applications, the initial value and the stability of the V  
V
REF  
(5V)  
/2  
REF  
input voltage become even more important. For example, if  
the span is reduced to 2.5V, the analog input LSB voltage  
value is correspondingly reduced from 20mV (5V span) to  
ICL7611  
300  
-
“SPAN”/2  
TO V  
TO V  
/2  
REF  
FS  
+
ADJ.  
0.1µF  
10mV and 1 LSB at the V  
/2 input becomes 5mV. As can  
REF  
be seen, this reduces the allowed initial tolerance of the  
reference voltage and requires correspondingly less  
absolute change with temperature variations. Note that  
spans smaller than 2.5V place even tighter requirements on  
the initial accuracy and stability of the reference source.  
IN(-)  
ZERO SHIFT VOLTAGE  
FIGURE 13. OFFSETTING THE ZERO OF THE ADC080X AND  
PERFORMING AN INPUT RANGE (SPAN)  
ADJUSTMENT  
In general, the reference voltage will require an initial  
adjustment. Errors due to an improper value of reference  
voltage appear as full scale errors in the A/D transfer  
10  
ADC0803, ADC0804  
function. IC voltage regulators may be used for references if  
Loads less than 50pF, such as driving up to 7 A/D converter  
clock inputs from a single CLK R pin of 1 converter, are  
allowed. For larger clock line loading, a CMOS or low power  
TTL buffer or PNP input logic should be used to minimize the  
loading on the CLK R pin (do not use a standard TTL buffer).  
the ambient temperature changes are not excessive.  
Zero Error  
The zero of the A/D does not require adjustment. If the  
minimum analog input voltage value, V  
, is not ground, a  
lN(MlN)  
Restart During a Conversion  
zero offset can be done. The converter can be made to output  
0000 0000 digital code for this minimum input voltage by  
If the A/D is restarted (CS and WR go low and return high)  
during a conversion, the converter is reset and a new  
conversion is started. The output data latch is not updated if  
the conversion in progress is not completed. The data from  
the previous conversion remain in this latch.  
biasing the A/D V  
IN(-)  
input at this V value (see  
lN(MlN)  
Applications section). This utilizes the differential mode  
operation of the A/D.  
The zero error of the A/D converter relates to the location of  
the first riser of the transfer function and can be measured by  
Continuous Conversions  
grounding the V  
input and applying a small magnitude  
input. Zero error is the difference  
IN(-)  
In this application, the CS input is grounded and the WR  
input is tied to the INTR output. This WR and INTR node  
should be momentarily forced to logic low following a power-  
up cycle to insure circuit operation. See Figure 17 for details.  
positive voltage to the V  
IN(+)  
between the actual DC input voltage which is necessary to  
just cause an output digital code transition from 0000 0000 to  
1
1
0000 0001 and the ideal / LSB value ( / LSB = 9.8mV for  
2
2
V
/2 = 2.500V).  
10K  
REF  
5V (V  
)
REF  
Full Scale Adjust  
ADC0803 - ADC0804  
150pF  
The full scale adjustment can be made by applying a  
1
2
3
4
5
6
7
8
9
CS  
V+ 20  
1
+
differential input voltage which is 1 / LSB down from the  
2
RD  
CLK R  
19  
18  
17  
16  
15  
14  
10µF  
desired analog full scale voltage range and then adjusting  
DB  
DB  
DB  
DB  
DB  
WR  
0
1
2
3
4
LSB  
the magnitude of the V  
/2 input (pin 9) for a digital output  
N.O.  
REF  
code which is just changing from 1111 1110 to 1111 1111.  
When offsetting the zero and using a span-adjusted V  
CLK IN  
INTR  
START  
/2  
MlN  
REF  
V
V
(+)  
(-)  
IN  
IN  
DATA  
ANALOG  
INPUTS  
voltage, the full scale adjustment is made by inputting V  
OUTPUTS  
to the V  
IN(+)  
input of the A/D and applying a voltage to the  
IN(-)  
AGND  
/2  
DB 13  
5
DB 12  
6
V
input which is given by:  
V
REF  
(V  
V  
256  
)
MAX  
MIN  
V
f
= V  
1.5 ----------------------------------------- ,  
MSB  
IN(+) SADJ  
MAX  
10 DGND  
DB 11  
7
where:  
FIGURE 17. FREE-RUNNING CONNECTION  
V
V
= the high end of the analog input range, and  
MAX  
= the low end (the offset zero) of the analog range.  
(Both are ground referenced.)  
MIN  
Driving the Data Bus  
This CMOS A/D, like MOS microprocessors and memories,  
will require a bus driver when the total capacitance of the  
data bus gets large. Other circuItry, which is tied to the data  
bus, will add to the total capacitive loading, even in three-  
state (high-impedance mode). Back plane busing also  
greatly adds to the stray capacitance of the data bus.  
Clocking Option  
The clock for the A/D can be derived from an external source  
such as the CPU clock or an external RC network can be  
added to provIde self-clocking. The CLK IN (pin 4) makes  
use of a Schmitt trigger as shown in Figure 16.  
There are some alternatives available to the designer to  
handle this problem. Basically, the capacitive loading of the  
data bus slows down the response time, even though DC  
specifications are still met. For systems operating with a  
relatively slow CPU clock frequency, more time is available  
in which to establish proper logic levels on the bus and  
therefore higher capacitive loads can be driven (see Typical  
Performance Curves).  
CLK R  
1
19  
4
f
ADC0803-  
ADC0804  
CLK  
1.1 RC  
R
R
10kΩ  
CLK IN  
C
CLK  
FIGURE 16. SELF-CLOCKING THE A/D  
At higher CPU clock frequencies time can be extended for  
I/O reads (and/or writes) by inserting wait states (8080) or  
using clock-extending circuits (6800).  
Heavy capacitive or DC loading of the CLK R pin should be  
avoided as this will disturb normal converter operation.  
11  
ADC0803, ADC0804  
Finally, if time is short and capacitive loading is high, external  
significant bits (MS) and one with the 4 least-significant bits  
(LS). The output is then interpreted as a sum of fractions  
times the full scale voltage:  
bus drivers must be used. These can be three-state buffers  
(low power Schottky is recommended, such as the 74LS240  
series) or special higher-drive-current products which are  
designed as bus drivers. High-current bipolar bus drivers  
with PNP inputs are recommended.  
MS LS  
V
=
-------- + --------- (5.12)V .  
OUT  
16 256  
10kΩ  
Power Supplies  
150pF  
5.120V  
1
2
3
20  
19  
18  
17  
16  
15  
14  
13  
12  
11  
Noise spikes on the V+ supply line can cause conversion  
errors as the comparator will respond to this noise. A  
low-inductance tantalum filter capacitor should be used  
close to the converter V+ pin, and values of 1µF or greater  
are recommended. If an unregulated voltage is available in  
the system, a separate 5V voltage regulator for the converter  
(and other analog circuitry) will greatly reduce digital noise  
on the V+ supply. An lCL7663 can be used to regulate such  
a supply from an input as low as 5.2V.  
+
10µF  
TANTALUM  
LSB  
N.O.  
4
5
START  
(+)  
ADC0803-  
ADC0804  
V
6
IN  
0.1µF  
5V  
7
AGND  
8
2.560V  
/2  
9
V
REF  
MSB  
Wiring and Hook-Up Precautions  
10  
0.1µF  
1.3kΩ  
LEDs  
(8)  
Standard digital wire-wrap sockets are not satisfactory for  
breadboarding with this A/D converter. Sockets on PC  
boards can be used. All logic signal wires and leads should  
be grouped and kept as far away as possible from the  
analog signal leads. Exposed leads to the analog inputs can  
cause undesired digital noise and hum pickup; therefore,  
shielded leads may be necessary in many applications.  
DGND  
(8)  
FIGURE 18. BASIC TESTER FOR THE A/D  
For example, for an output LED display of 1011 0110, the  
MS character is hex B (decimal 11) and the LS character is  
hex (and decimal) 6, so:  
11  
6
V
= ------ + --------- (5.12) = 3.64V.  
   
A single-point analog ground should be used which is  
separate from the logic ground points. The power supply  
bypass capacitor and the self-clockIng capacitor (if used)  
OUT  
16 256  
Figures 19 and 20 show more sophisticated test circuits.  
should both be returned to digital ground. Any V  
/2  
REF  
V
bypass capacitors, analog input filter capacitors, or input  
signal shielding should be returned to the analog ground  
8-BIT  
A/D UNDER  
TEST  
ANALOG OUTPUT  
10-BIT  
DAC  
point. A test for proper grounding is to measure the zero  
R
1
R
error of the A/D converter. Zero errors in excess of / LSB  
4
“B”  
ANALOG  
INPUTS  
-
can usually be traced to improper board layout and wiring  
(see Zero Error for measurement). Further information can  
be found in Application Note AN018.  
+
“C”  
A1  
R
R
100R  
100X ANALOG  
-
Testing the A/D Converter  
+
ERROR VOLTAGE  
“A”  
A2  
There are many degrees of complexity associated with testing  
an A/D converter. One of the simplest tests is to apply a  
known analog input voltage to the converter and use LEDs to  
display the resulting digital output code as shown in Figure 18.  
FIGURE 19. A/D TESTER WITH ANALOG ERROR OUTPUT. THIS  
CIRCUIT CAN BE USED TO GENERATE “ERROR  
PLOTS” OF FIGURE 11.  
For ease of testing, the V  
/2 (pin 9) should be supplied  
REF  
with 2.560V and a V+ supply voltage of 5.12V should be  
used. This provides an LSB value of 20mV.  
DIGITAL  
INPUTS  
DIGITAL  
OUTPUTS  
V
ANALOG  
10-BIT  
DAC  
A/D UNDER  
TEST  
If a full scale adjustment is to be made, an analog input  
1
voltage of 5.090V (5.120 - 1 / LSB) should be applied to  
2
the V  
V
pin with the V  
pin grounded. The value of the  
IN(-)  
IN(+)  
/2 input voltage should be adjusted until the digital  
FIGURE 20. BASIC “DIGITAL” A/D TESTER  
REF  
output code is just changing from 1111 1110 to 1111 1111.  
This value of V /2 should then be used for all the tests.  
Typical Applications  
REF  
Interfacing 8080/85 or Z-80 Microprocessors  
The digital-output LED display can be decoded by dividing  
the 8 bits into 2 hex characters, one with the 4 most-  
12  
ADC0803, ADC0804  
This converter has been designed to directly interface with  
Interfacing 6800 Microprocessor Derivatives (6502,  
etc.)  
8080/85 or Z-80 Microprocessors. The three-state output  
capability of the A/D eliminates the need for a peripheral  
interface device, although address decoding is still required  
to generate the appropriate CS for the converter. The A/D  
can be mapped into memory space (using standard  
The control bus for the 6800 microprocessor derivatives does  
not use the RD and WR strobe signals. Instead it employs a  
single R/W line and additional timing, if needed, can be derived  
from the φ2 clock. All I/O devices are memory-mapped in the  
6800 system, and a special signal, VMA, indicates that the  
current address is valid. Figure 23 shows an interface  
memory-address decoding for CS and the MEMR and  
MEMW strobes) or it can be controlled as an I/O device by  
using the I/OR and I/OW strobes and decoding the address  
bits A0 A7 (or address bits A8 A15, since they will  
contain the same 8-bit address information) to obtain the CS  
input. Using the I/O space provides 256 additional  
addresses and may allow a simpler 8-bit address decoder,  
but the data can only be input to the accumulator. To make  
use of the additional memory reference instructions, the A/D  
should be mapped into memory space. See AN020 for more  
discussion of memory-mapped vs I/O-mapped interfaces. An  
example of an A/D in I/O space is shown in Figure 21.  
schematic where the A/D is memory-mapped in the 6800  
1
system. For simplicity, the CS decoding is shown using /  
2
DM8092. Note that in many 6800 systems, an already decoded  
4/5 line is brought out to the common bus at pin 21. This can be  
tied directly to the CS pin of the A/D, provided that no other  
devices are addressed at HEX ADDR: 4XXX or 5XXX.  
In Figure 24 the ADC080X series is interfaced to the MC6800  
microprocessor through (the arbitrarily chosen) Port B of the  
MC6820 or MC6821 Peripheral Interface Adapter (PlA). Here  
the CS pin of the A/D is grounded since the PlA is already  
memory-mapped in the MC6800 system and no CS decoding  
is necessary. Also notice that the A/D output data lines are  
connected to the microprocessor bus under program control  
through the PlA and therefore the A/D RD pin can be grounded.  
The standard control-bus signals of the 8080 (CS, RD and  
WR) can be directly wired to the digital control inputs of the  
A/D, since the bus timing requirements, to allow both starting  
the converter, and outputting the data onto the data bus, are  
met. A bus driver should be used for larger microprocessor  
systems where the data bus leaves the PC board and/or  
must drive capacitive loads larger than 100pF.  
Application Notes  
NOTE #  
DESCRIPTION  
It is useful to note that in systems where the A/D converter is  
1 of 8 or fewer I/O-mapped devices, no address-decoding  
circuitry is necessary. Each of the 8 address bits (A0 to A7)  
can be directly used as CS inputs, one for each I/O device.  
AN016  
“Selecting A/D Converters”  
AN018  
“Do’s and Don’ts of Applying A/D Converters”  
AN020  
“A Cookbook Approach to High Speed Data Acquisition  
and Microprocessor Interfacing”  
Interfacing the Z-80 and 8085  
The Z-80 and 8085 control buses are slightly different from  
that of the 8080. General RD and WR strobes are provided  
and separate memory request, MREQ, and I/O request,  
IORQ, signals have to be combined with the generalized  
strobes to provide the appropriate signals. An advantage of  
operating the A/D in I/O space with the Z-80 is that the CPU  
will automatically insert one wait state (the RD and WR  
strobes are extended one clock period) to allow more time  
for the I/O devices to respond. Logic to map the A/D in I/O  
space is shown in Figure 22. By using MREQ in place of  
IORQ, a memory-mapped configuration results.  
AN030  
“The ICL7104 - A Binary Output A/D Converter for  
Microprocessors”  
Additional I/O advantages exist as software DMA routines are  
available and use can be made of the output data transfer  
which exists on the upper 8 address lines (A8 to A15) during  
I/O input instructions. For example, MUX channel selection for  
the A/D can be accomplished with this operating mode.  
The 8085 also provides a generalized RD and WR strobe, with  
an IO/M line to distinguish I/O and memory requests. The circuit  
of Figure 22 can again be used, with IO/M in place of IORQ for  
a memory-mapped interface, and an extra inverter (or the logic  
equivalent) to provide IO/M for an I/O-mapped connection.  
13  
ADC0803, ADC0804  
INT (14)  
I/O WR (27) (NOTE)  
I/O RD (25) (NOTE)  
10K  
ADC0803 - ADC0804  
+
10µF  
1
2
3
4
5
6
7
8
9
CS  
V+ 20  
5V  
RD  
CLK R  
19  
18  
17  
16  
15  
14  
LSB  
DB  
DB  
DB  
DB  
DB  
WR  
DB (13) (NOTE)  
0
DB (16) (NOTE)  
1
DB (11) (NOTE)  
2
DB (9) (NOTE)  
3
DB (5) (NOTE)  
4
DB (18) (NOTE)  
5
DB (20) (NOTE)  
6
DB (7) (NOTE)  
7
0
1
2
3
4
CLK IN  
INTR  
V
V
(+)  
(-)  
IN  
IN  
ANALOG  
INPUTS  
AGND  
/2  
DB 13  
5
DB 12  
6
150pF  
V
REF  
MSB  
10 DGND  
DB 11  
7
5V  
V+  
OUT  
B
T
T
T
T
T
T
AD (36)  
15  
AD (39)  
14  
AD (38)  
13  
AD (37)  
12  
AD (40)  
11  
AD (1)  
10  
5
4
3
2
1
0
5
4
3
2
1
0
B
B
B
B
B
8131  
BUS  
COMPARATOR  
NOTE: Pin numbers for 8228 System Controller: Others are 8080A.  
FIGURE 21. ADC080X TO 8080A CPU INTERFACE  
14  
ADC0803, ADC0804  
IRQ (4)[D]††  
R/W (34) [6]  
10µF  
10K  
ADC0803 - ADC0804  
+
1
2
3
4
5
6
7
8
9
CS  
V+ 20  
A B C  
RD  
CLK R  
19  
18  
17  
16  
15  
14  
5V (8) 1 2 3  
LSB  
DB  
DB  
DB  
DB  
DB  
WR  
D
D
D
D
D
D
D
D
(33) [31]  
(32) [29]  
(31) [K]  
(30) [H]  
(29) [32]  
(28) [30]  
(27) [L]  
(26) [J]  
0
1
2
3
4
0
1
2
3
4
5
6
7
CLK IN  
INTR  
RD  
RD  
ANALOG  
INPUTS  
2
3
V
V
(+)  
(-)  
IN  
IN  
IORQ  
WR  
ADC0803-  
ADC0804  
AGND  
/2  
DB 13  
5
DB 12  
6
V
REF  
150pF  
MSB  
10 DGND  
DB 11  
7
WR  
1
2
3
4
74C32  
A
A
A
A
(22) [34]  
(23) [N]  
(24) [M]  
(25) [33]  
12  
13  
14  
15  
6
1
/
DM8092  
2
5
VMA (5) [F]  
Numbers in parentheses refer to MC6800 CPU Pinout.  
†† Numbers or letters in brackets refer to standard MC6800 System Common Bus Code.  
FIGURE 22. MAPPING THE A/D AS AN  
I/O DEVICE FOR USE  
FIGURE 23. ADC080X TO MC6800 CPU INTERFACE  
WITH THE Z-80 CPU  
18  
CB  
CB  
1
2
19  
10K  
ADC0803 - ADC0804  
MC6820  
(MCS6520)  
1
2
3
4
5
6
7
8
9
CS  
V+ 20  
5V  
RD  
CLK R  
PIA  
19  
18  
17  
16  
15  
14  
10  
11  
12  
13  
14  
15  
16  
17  
LSB  
DB  
DB  
DB  
DB  
DB  
PB  
WR  
0
1
2
3
4
0
1
2
3
4
5
6
7
PB  
PB  
PB  
PB  
PB  
PB  
PB  
CLK IN  
INTR  
V
V
(+)  
(-)  
IN  
IN  
ANALOG  
INPUTS  
AGND  
/2  
DB 13  
5
DB 12  
6
V
REF  
150pF  
MSB  
10 DGND  
DB 11  
7
FIGURE 24. ADC080X TO MC6820 PIA INTERFACE  
15  
ADC0803, ADC0804  
Die Characteristics  
DIE DIMENSIONS  
PASSIVATION  
101 mils x 93 mils  
Type: Nitride over Silox  
Nitride Thickness: 8kÅ  
Silox Thickness: 7kÅ  
METALLIZATION  
Type: Al  
Thickness: 10kÅ ±1kÅ  
Metallization Mask Layout  
ADC0803, ADC0804  
AGND  
V
(-)  
V
(+)  
IN  
INTR  
CLK IN  
IN  
WR  
V
/2  
REF  
RD  
CS  
DGND  
DB  
7 (MSB)  
DB  
6
5
V+ OR V  
V+ OR V  
REF  
REF  
DB  
CLK R  
DB  
DB  
DB  
DB  
DB  
0
4
3
2
1
16  
ADC0803, ADC0804  
Dual-In-Line Plastic Packages (PDIP)  
E20.3 (JEDEC MS-001-AD ISSUE D)  
N
20 LEAD DUAL-IN-LINE PLASTIC PACKAGE  
E1  
INDEX  
AREA  
INCHES  
MILLIMETERS  
1 2  
3
N/2  
SYMBOL  
MIN  
-
MAX  
0.210  
-
MIN  
-
MAX  
5.33  
-
NOTES  
-B-  
A
A1  
A2  
B
4
-A-  
0.015  
0.115  
0.014  
0.045  
0.008  
0.980  
0.005  
0.300  
0.240  
0.39  
2.93  
0.356  
1.55  
0.204  
24.89  
0.13  
7.62  
6.10  
4
D
E
BASE  
0.195  
0.022  
0.070  
0.014  
1.060  
-
4.95  
0.558  
1.77  
0.355  
26.9  
-
-
PLANE  
A2  
A
-C-  
C
-
SEATING  
PLANE  
L
C
L
B1  
C
8
D1  
B1  
-
eA  
A1  
A
D1  
e
D
5
eC  
C
eB  
B
D1  
E
5
0.010 (0.25) M  
B S  
0.325  
0.280  
8.25  
7.11  
6
E1  
e
5
NOTES:  
0.100 BSC  
0.300 BSC  
2.54 BSC  
7.62 BSC  
-
1. Controlling Dimensions: INCH. In case of conflict between English  
e
e
6
A
B
and Metric dimensions, the inch dimensions control.  
-
0.430  
0.150  
-
10.92  
3.81  
7
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.  
L
0.115  
2.93  
4
9
3. Symbols are defined in the “MO Series Symbol List” in Section 2.2  
of Publication No. 95.  
N
20  
20  
4. Dimensions A, A1 and L are measured with the package seated in  
Rev. 0 12/93  
JEDEC seating plane gauge GS-3.  
5. D, D1, and E1 dimensions do not include mold flash or protrusions.  
Mold flash or protrusions shall not exceed 0.010 inch (0.25mm).  
e
6. E and  
are measured with the leads constrained to be perpen-  
A
-C-  
dicular to datum  
.
7. e and e are measured at the lead tips with the leads uncon-  
B
C
strained. e must be zero or greater.  
C
8. B1 maximum dimensions do not include dambar protrusions. Dam-  
bar protrusions shall not exceed 0.010 inch (0.25mm).  
9. N is the maximum number of terminal positions.  
10. Corner leads (1, N, N/2 and N/2 + 1) for E8.3, E16.3, E18.3, E28.3,  
E42.6 will have a B1 dimension of 0.030 - 0.045 inch (0.76 - 1.14mm).  
All Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems.  
Intersil Corporation’s quality certifications can be viewed at website www.intersil.com/quality/iso.asp.  
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice.  
Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. How-  
ever, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No  
license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.  
For information regarding Intersil Corporation and its products, see web site www.intersil.com  
17  

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