Obsolescence Notice
This product is obsolete.
This information is available for your
convenience only.
For more information on
Zarlink’s obsolete products and
replacement product lists, please visit
http://products.zarlink.com/obsolete_products/
THIS DOCUMENT IS FOR MAINTENANCE
PURPOSES ONLY AND IS NOT
RECOMMENDED FOR NEW DESIGNS
JULY 1994
DS2431-2.1
MV95308
30MHz 8-BIT CMOS VIDEO DAC
The MV95308 is a CMOS 8-bit, 30MHz Digital to
Analog converter, designed for use in both video graphics
and general digital television applications.
A very low external component count has been
achieved by including the loop amplifier and reference
voltage source on chip.
The device contains a data input register and registered
video controls (BLANK, REFWHITE, OVERBRT and SYNC).
These control inputs and associated internal circuitry allows
the MV95308 to be used in video graphics systems by
providing the necessary video pedestal levels. The STRDAC
input allows the video pedestals to be disabled in
conventional DAC applications.
This device is capable of directly driving 75
Ω
lines with
standard RS-343A or RS-170 video levels, using the
appropriate R
SET
external resistor.
Pull up resistors have been added to tie all unused
control inputs into their inactive (High) states.
BLANK
CLK
MSB D
7
D
6
D
5
D
4
D
3
D
2
D
1
LSB D
0
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
DD
REFWHITE
0VERBR T
SYNC
STRD AC
I
OUT
GND
I
OUT
R
SET
V
REF
DP20
MP20
Fig.1 Pin connections - top view
FEATURES
s
Low Power Consumption (180mW Typ)
s
30MHz Pipeline Operation
s
±
1 LSB Differential Linearity Error
s
±
1 LSB Integral Linearity Error
s
RS-343A/RS-170 Compatible Levels
s
On Chip Reference Voltage Source
s
Guaranteed Monotonic
s
Drives 75
Ω
Loads Directly
s
Single 5V Power Supply
ORDERING INFORMATION
MV95308 ADG
(Military - Ceramic DIL Package)
MV95308 CDP
(Commercial - Plastic DIL Package)
MV95308 CMP
(Commercial - Miniature Plastic DIL
Package)
APPLICATIONS
s
Data Conversion (general)
s
Computer Graphics
s
Waveform Synthesis
s
Consumer TV
s
Instrumentation
ABSOLUTE MAXIMUM RATINGS
(Reference to GND)
DC Supply Voltage, V
DD
-0.3 to +7V
Digital Input Voltage
-0.3 to V
DD
+0.3V
Analog Output Short Circuit Duration
Indefinite
Ambient Operating Temperature A grade -55
°
C to +125
°
C
C grade
0
°
C to + 70
°
C
Storage Temperature Range
-55
°
C to +125
°
C
Fig.2 Block diagram of MV95308
MV95308
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions (unless otherwise stated):
As specified in recommended operating conditions. Full temperature range: A grade = -55
°
C to +125
°
C, C grade = 0 to 70
°
C
DC CHARACTERISTICS
Parameter
Resolution
Integral linearity error
Differential linearity error
Gain error
Analog output
Grey scale current range
10% Over Bright level relative to
White level
White level relative to Blank level
Black level relative to Blank level
White level relative to Black level
Blank level
Sync level
LSB size
Output compliance
Digital inputs
High level I/P voltage
Low level I/P voltage
High level I/P current
Low level I/P current
Internal voltage reference (V
REF
)
V
REF
temperature coefficient
Symbol
Temp
(
°
C)
Full
25
Full
25
Full
25
25
25
25
25
25
25
LSB
V
OC
V
IH
V
IL
I
IH
I
IL
V
REF
25
25
25
25
25
25
25
25
Full
107
26
275
20
Min.
8
±
0.5
±
0.5
±
1%
8.8
255
27
10
276
100
21
7.5
255
92.5
111
40
0
2.58
±
1
±
1
±
5%
Value
Typ.
Max.
Units
Bits
LSB
LSB
LSB
LSB
%
mA
LSB
LSB
IRE
LSB
IRE
LSB
IRE
LSB
IRE
LSB
IRE
LSB
mV
V
V
V
µ
A
µ
A
V
V
ppm/
°
C
Conditions
INL
DNL
Of full scale
28
277
22
144424443
75
Ω
singly
terminated load
R
SET
= 1.8k
Ω
(graphics mode)
115
-0.3
3
GND-0.3
+1.5
V
DD
+0.3
1.2
+1
-1
1.05
1.10
0.95
0.90
1.0
40
AC CHARACTERISTICS
(Refer to Fig. 3)
Parameter
Max clock rate
Clock high time
Clock low time
Data and control setup time
Data and control hold time
Analog output delay
Analog output rise/fall time
Analog output settling time
Glitch energy
V
DD
supply current
Symbol
f
MAX
t
CLKH
t
CLKL
t
SU
t
H
t
DLY
t
RF
t
S
IDD
Temp
(
°
C)
Full
25
25
25
25
25
25
25
25
25
Min.
30
10
10
8
2
10
3
15
100
30
36
Value
Typ.
Max.
Units
MHz
ns
ns
ns
ns
ns
ns
ns
pV-sec
mA
mA
Conditions
maximum
guaranteed freq.
6
fc = 15MHz
fc = 30MHz
75
Ω
5.0V
±
0.5V
1.8k
Ω
1.2k
Ω
THERMAL CHARACTERISTICS
Thermal Resistance
Chip to case
θ
jC
Chip to ambient
θ
jA
DP
20
75
MP
30
93
°
C/W
°
C/W
RECOMMENDED OPERATING CONDITIONS
R
LOAD
(I
OUT
and I
OUT
)
V
DD
R
SET
(graphics applications)
R
SET
(straight DAC applications)
2
MV95308
CIRCUIT DESCRIPTION
As illustrated in the function block diagram, Fig. 2, the
MV95308 contains an 8-bit D-to-A converter, input registers,
a loop amplifier and a voltage reference.
On the falling edge of each clock cycle, as shown in Fig. 3,
eight data bits are latched into the device and passed to the
8-bit D-to-A converter. Also latched on the falling edge of the
clock signal, the SYNC and BLANK inputs add the
necessary weighted currents to the analog outputs to
produce the required output levels for use in video
applications. Table 1 details how the SYNC, BLANK,
REFWHITE and OVERBRT inputs modify the DAC output
levels.
To obtain a high data throughput rate, the decoding logic of
the MV95308 is fully pipelined. This introduces a one clock
cycle delay between the latching of the input data and the
resultant DAC output.
It also ensures synchronisation of the internal data and a
minimal output glitch energy.
The DAC employed by the MV95308 eliminates the need
for precision component ratios by using segmented architecture
in which equal weight bit currents are either routed to I
OUT
or
I
OUT
. The use of identical current sources and current steering
their outputs means that monotonicity is guaranteed.
The MV95308 eliminates the need for an external voltage
reference by providing a nominally 1.0V reference on chip. An
on-chip loop amplifier also provides stability of the full scale
output current against power supply and temperature
variations. The full scale output current is set by an external
resistor R
SET
. By adjustment of this value it is possible to
implement RS-343A or RS-170 video levels as explained in the
application notes.
Fig.3 Timing diagram
Description
REFWHITE + 10%
REFWHITE
FULL WHITE
OVERBRIGHT
FULL BLACK
BLANK
DATA-SYNC
SYNC
STRDAC MODE
STRDAC
1
1
1
1
1
1
1
1
0
SYNC
1
1
1
1
1
1
0
0
X
BLANK
1
1
1
1
1
0
1
0
1
REFWHITE
0
0
1
1
1
X
1
X
1
OVERBRT
0
1
1
0
1
X
1
X
X
OUTPUT
DATA
X
X
$FF
DATA
$00
X
DATA
X
DATA
I
OUT
(LSB)
414
387
387
DATA +
132 + 27
132
111
DATA + 21
0
DATA
Table 1: Video output truth table
3
