MM74C905 12-Bit Successive Approximation Register
October 1987
Revised January 1999
MM74C905
12-Bit Successive Approximation Register
General Description
The MM74C905 CMOS 12-bit successive approximation
register contains all the digit control and storage necessary
for successive approximation analog-to-digital conversion.
Because of the unique capability of CMOS to switch to
each supply rail without any offset voltage, it can also be
used in digital systems as the control and storage element
in repetitive routines.
Features
s
Wide supply voltage range:
s
Guaranteed noise margin:
s
High noise immunity:
3.0V to 15V
1.0V
Fan out of 2 driving 74L
0.45 V
CC
(typ)
s
Low power TTL compatibility:
s
Provision for register extension or truncation
s
Operates in START/STOP or continuous conversion
mode
s
Drive ladder switches directly. For 10 bits or less with
50k/100k R/2R ladder network
Ordering Code:
Order Number
MM74C905N
Package Number
N24A
Package Description
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-010, 0.600” Wide
Connection Diagram
Pin Assignments for DIP
© 1999 Fairchild Semiconductor Corporation
DS005910.prf
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MM74C905
Truth Table
Time
t
n
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
D
X
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X
X
X
H
=
HIGH Level
L
=
LOW Level
X
=
Don’t Care
NC
=
No Change
Inputs
S
L
H
H
H
H
H
H
H
H
H
H
H
H
H
X
X
E
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
D0
X
X
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X
X
Q11
X
L
D11
D11
D11
D11
D11
D11
D11
D11
D11
D11
D11
D11
D11
H
Q10
X
H
L
D10
D10
D10
D10
D10
D10
D10
D10
D10
D10
D10
D10
NC
Q9
X
H
H
L
D9
D9
D9
D9
D9
D9
D9
D9
D9
D9
D9
NC
Q8
X
H
H
H
L
D8
D8
D8
D8
D8
D8
D8
D8
D8
D8
NC
Q7
X
H
H
H
H
L
D7
D7
D7
D7
D7
D7
D7
D7
D7
NC
Outputs
Q6
X
H
H
H
H
H
L
D6
D6
D6
D6
D6
D6
D6
D6
NC
Q5
X
H
H
H
H
H
H
L
D5
D5
D5
D5
D5
D5
D5
NC
Q4
X
H
H
H
H
H
H
H
L
D4
D4
D4
D4
D4
D4
NC
Q3
X
H
H
H
H
H
H
H
H
L
D3
D3
D3
D3
D3
NC
Q2
X
H
H
H
H
H
H
H
H
H
L
D2
D2
D2
D2
NC
Q1
X
H
H
H
H
H
H
H
H
H
H
L
D1
D1
D1
NC
Q0
X
H
H
H
H
H
H
H
H
H
H
H
L
D0
D0
NC
CC
X
H
H
H
H
H
H
H
H
H
H
H
H
L
L
NC
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2
MM74C905
Absolute Maximum Ratings
(Note 1)
Voltage at Any Pin
Operating Temperature Range (T
A
)
Storage Temperature Range (T
S
)
Power Dissipation (P
D
)
Dual-In-Line
Small Outline
Operating V
CC
Range
700 mW
500 mW
3.0V to 15V
−0.3V
to V
CC
+0.3V
−40°C
to
+85°C
−65°C
to
+150°C
Absolute Maximum V
CC
Lead Temperature (T
L
)
(Soldering, 10 seconds)
16V
260°C
Note 1:
“Absolute Maximum Ratings” are those values beyond which the
safety of the device cannot be guaranteed. Except for “Operating Tempera-
ture Range” they are not meant to imply that the devices should be oper-
ated at these limits. The table of “Electrical Characteristics” provides
conditions for actual device operation.
DC Electrical Characteristics
Min/Max limits apply across temperature range unless otherwise noted
Symbol
CMOS TO CMOS
V
IN(1)
V
IN(0)
V
OUT(1)
V
OUT(0)
I
IN(1)
I
IN(0)
I
CC
V
IN(1)
V
IN(0)
V
OUT(1)
V
OUT(0)
I
SOURCE
I
SOURCE
I
SINK
I
SINK
Logical “1” Input Voltage
Logical “0” Input Voltage
Logical “1” Output Voltage
Logical “0” Output Voltage
Logical “1” Input Current
Logical “0” Input Current
Supply Current
Logical “1” Input Voltage
Logical “0” Input Voltage
Logical “1” Output Voltage
Logical “0” Output Voltage
Output Source Current
(P-Channel)
Output Source Current
(P-Channel)
Output Sink Current
(N-Channel)
Output Sink Current
(N-Channel)
R
SOURCE
R
SINK
Q11–Q0 Outputs
Q11–Q0 Outputs
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V, I
O
= −10 µA
V
CC
=
10V, I
O
= −10 µA
V
CC
=
5.0V, I
O
=
10
µA
V
CC
=
10V, I
O
=
10
µA
V
CC
=
15V, V
IN
=
15V
V
CC
=
15V, V
IN
=
0V
V
CC
=
15V
V
CC
=
4.75V
V
CC
=
4.75V
V
CC
=
4.75V, I
O
= −360 µA
V
CC
=
4.75V, I
O
=
360
µA
V
CC
=
5.0V, V
OUT
=
0V
T
A
=
25°C
V
CC
=
10V, V
OUT
=
0V
T
A
=
25°C
V
CC
=
5.0V, V
OUT
=
V
CC
T
A
=
25°C
V
CC
=
10V, V
OUT
=
V
CC
T
A
=
25°C
V
CC
=
10V
±5%
V
OUT
=
V
CC
−
0.3V
T
A
=
25°C
V
CC
=
10V
±5%
V
OUT
=
0.3V
T
A
=
25°C
80
230
Ω
150
350
Ω
8.0
16
mA
1.75
3.6
mA
−8.0
−15
mA
−1.75
−3.3
2.4
0.4
V
CC
−
1.5
0.8
−1.0
0.005
−0.005
0.05
300
4.5
9.0
0.5
1.0
1.0
3.5
8.0
1.5
2.0
V
V
V
V
V
V
V
V
µA
µA
µA
V
V
V
V
mA
Parameter
Conditions
Min
Typ
Max
Units
CMOS/LPTTL INTERFACE
OUTPUT DRIVE (See Family Characteristics Data Sheet)
3
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MM74C905
AC Electrical Characteristics
T
A
=
25
°
C, C
L
=
50 pF, unless otherwise specified
Symbol
t
pd
Parameter
Propagation Delay Time from
Clock Input to Outputs
(Q0–Q11) (t
pd(Q)
)
t
pd
t
pd
Propagation Delay Time from
Clock Input to D0 (t
pd(D0)
)
Propagation Delay Time from
Register Enable (E) to Output
(Q11) (t
pd(E)
)
t
pd
t
S
t
S
t
W
t
r
, t
f
f
MAX
C
CK
C
IN
C
PD
Propagation Delay Time from
Clock to CC (t
pd(CC)
)
Data Input Set-Up Time
Start Input Set-Up Time
Minimum Clock Pulse Width
Maximum Clock Rise and Fall Time
Maximum Clock Frequency
Clock Input Capacitance
Input Capacitance
Power Dissipation Capacitance
(Note 2)
Conditions
Min
Typ
200
80
180
70
190
75
190
75
80
30
80
30
250
100
125
50
15
5.0
2.0
5.0
4.0
10
10
5
100
Max
350
150
325
125
350
150
350
0.50
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
µs
µs
MHz
MHz
pF
pF
pF
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
V
CC
=
5.0V
V
CC
=
10V
Clock Input (Note 3)
Any other Input (Note 3)
(Note 4)
Note 2:
AC Parameters are guaranteed by DC correlated testing.
Note 3:
Capacitance is guaranteed by periodic testing.
Note 4:
C
PD
determines the no load AC power consumption of any CMOS device. For complete explanation, see Family Characteristics Application Note—
AN-90.
Typical Performance Characteristics
R
SINK
vs Temperature
R
SOURCE
vs Temperature
•These points are guaranteed by automatic testing.
•These points are guaranteed by automatic testing.
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4
MM74C905
Timing Diagram
5
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