![](http://datasheet.mmic.net.cn/290000/ZN448_datasheet_16190451/ZN448_1.png)
WR (START CONVERSION)
BUSY (END OF CONVERSION)
DB
0
(LSB)
RD (OUTPUT ENABLE)
DB
1
CLOCK
DB
2
DB
3
R
EXT
DB
4
V
IN
DB
5
V
REF
IN
DB
6
V
REF
OUT
DB
7
(MSB)
GROUND
+V
CC
(+5V)
18
1
17
2
16
3
15
4
14
5
13
6
12
7
11
8
10
9
WR (START CONVERSION)
BUSY (END OF CONVERSION)
DB
0
(LSB)
RD (OUTPUT ENABLE)
DB
1
CLOCK
DB
2
DB
3
R
EXT
DB
4
V
IN
DB
5
V
REF
IN
DB
6
V
REF
OUT
DB
7
(MSB)
GROUND
+V
CC
(+5V)
18
1
17
2
16
3
15
4
14
5
13
6
12
7
11
8
10
9
0
°
C to +70
°
C
0
°
C to +70
°
C
0
°
C to +70
°
C
0.5
1
1
ZN448/ZN449
8-BIT MICROPROCESSOR COMPATIBLE A-D CONVERTER
DS3013 - 2.2
The ZN448 and ZN449 are 8-bit successive
approximation A-D converters designed to be easily
interfaced to microprocessors. All active circuitry is contained
on-chip including a clock generator and stable 2.5V bandgap
reference, control logic and double buffered latches with
reference.
Only a reference resistor and capacitor, clock resistor and
capacitor and input resistors are required for operation with
either unipolar or bipolar input voltage.
FEATURES
I
Easy Interfacing to Microprocessor, or operates as a
'Stand-Alone' Converter
I
Fast: 9 microseconds Conversion time Guaranteed
I
Choice of Linearity: 0.5 LSB - ZN448, 1 LSB - ZN449
I
On-Chip Clock
I
Choice of On-Chip or External Reference Voltage
I
Unipolar or Bipolar Input Ranges
I
Commercial Temperature Range
ORDERING INFORMATION
Device type
ZN448E
ZN449D
ZN449E
Package
DP18
MP18
DP18
Operating
temperature
Linearity
error (LSB)
ZN448/9E (DP18)
ZN449D (MP18)
Fig.1 Pin connection - top view
Fig.2 System diagram
SUCCESSIVE
APPROXIMATION REGISTER
3-STATE BUFFERS
8-BIT DAC
2.5V
REFERENCE
CLOCK
GENERATOR
INTERFACE
AND
CONTROL
LOGIC
+
-
CK RC OR
EXT CLOCK
3
REXT
5
WR
4
BUSY
1
RD
2
18
17
16
15
14
13
12
DB0
11
DB7
VCC (+5V)
10
GROUND
9
VREF OUT
8
VREF IN
7
ANALOGUE
INPUT
6
COMPARATOR