SIPEX SP674AT883

HS574A/SP674A
12–Bit Sampling A/D Converters
■ Complete 12–bit A/D Converters with Sample–
■
■
■
■
Hold, Reference, Clock and Tri–state Outputs
Low Power Dissipation — 110mW Maximum
12–Bit Linearity Over Temperature
Fast Conversion time:
25µs Max (HS574A)
15µs Max (SP674A)
Monolithic Construction
DESCRIPTION…
The HS574A/SP674A Series are complete 12–bit successive–approximation A/D converters
integrated on a single die with tri-state output latches, an internal reference, clock and a sample–
hold. They feature 12–bit linearity over temperature, low power dissipation and fast conversion
time. They are available in commercial and military temperature ranges.
STS
28
DB11
27
DB10
DB9
25
26
DB8
24
DB7
23
DB6
22
NIBBLE A
DB5
21
DB4
20
DB3
19
DB2
18
NIBBLE B
DB1
17
DB0
16
DGND
15
NIBBLE C
THREE–STATE BUFFERS AND CONTROL
12–BIT SAR
12–BIT
CAPACITANCE
DAC
COMP
OSC
OFFSET/GAIN
TRIM
REF
CONTROL LOGIC
7.5K
15K
7.5K
N/C
1
VLOGIC
2
12/8
3
CS
4
5
A0
R/C
6
7
8
CE
VCC
REF
OUT
9
AGND
10
REF
IN
11
VEE
15K
7.5K
12
BIP
OFF
13
10V
IN
14
20V
IN
3
ABSOLUTE MAXIMUM RATINGS
VCC to Digital Common .................................................. 0 to +16.5V
VLOGIC to Digital Common ................................................... 0 to +7V
Analog Common to Digital Common ......................................... ±1V
Control Inputs to Digital Common ................. –0.5V to VLOGIC +0.5V
(CE, CS, A0, 12/8, R/C)
Analog Inputs to Analog Common ...................................... ±16.5V
(REF IN, BIP OFF, 10VIN)
20VIN to Analog Common ........................................................ ±24V
REF OUT ............................................... Indefinite short to common
Momentary short to VCC
Power Dissipation ............................................................. 1000mW
Lead Temperature, Soldering ................................... 300˚C, 10Sec
ΘJ/C ................................................................................... 45˚C/W
MTBF–25˚C Ground Base ................................ 2.915 million hours
MTBF–125˚C Missile Launch ...................... 10.16 thousand hours
•
CAUTION:
ESD (ElectroStatic Discharge) sensitive
device. Permanent damage may occur on
unconnected devices subject to high energy
electrostatic fields. Unused devices must be
stored in conductive foam or shunts.
Personnel should be properly grounded prior
to handling this device. The protective foam
should be discharged to the destination
socket before devices are removed.
Inputs exceeding +30% or –30% of FS will cause erratic performance.
SPECIFICATIONS
(Typical @ 25°C with VCC = +15V, VEE = 0V, VLOGIC = +5V unless otherwise noted)
PARAMETER
MIN.
TYP.
MAX.
UNIT
CONDITIONS
RESOLUTION
All models
12
Bits
ANALOG INPUTS
Input Ranges
Bipolar
±5, ±10
V
Unipolar
0 to +10, 0 to +20
V
Input Impedance
10 Volt Input
3.75
6.25
KΩ
20 Volt Input
15
25
KΩ
DIGITAL INPUTS
Logic Inputs CE, CS R/C, AO, 12/8
Logic 1
+2.4
+5.5
V
Logic 0
–0.3
+0.8
V
Current
±0.1
±50
µA
0V to +5.5V Input
Capacitance
5
pF
12/8 Control Input
Hardwire to VLOGIC or DIGITAL COMMON (SP574A only)
DIGITAL OUTPUTS
Logic Outputs DB11–DB0, STS
Logic 1
+2.4
V
ISOURCE ≤ 500µA
Logic 0
+0.4
V
ISINK ≤ 1.6mA
Leakage (High Z State)
±40
µA
Data bits only
Capacitance
5
pF
Parallel Data Output Codes
Unipolar
Positive true binary
Bipolar
Positive true offset binary
REFERENCE
Internal
10.00 ±0.1
V
Output Current
2
mA
Note 1
CONVERSION TIME
HS574A
12–Bit Conversion
13
25
µs
8–Bit Conversion
10
19
µs
SP674A
12–Bit Conversion
9
15
µs
8–Bit Conversion
6
11.25
µs
4
SPECIFICATIONS (continued)
(Typical @ 25°C with VCC = +15V, VEE = 0V, VLOGIC = +5V unless otherwise noted)
PARAMETER
MIN.
TYP.
MAX.
UNIT
ACCURACY
Linearity Error @ 25°C
–J, –S
±1.0
LSB
–K, –L, –T, –U
±0.5
LSB
Differential Linearity Error
–J, –S
11
Bits
11
Bits
–K, –L, –T, –U
12
Bits
12
Bits
Offset
Unipolar
±2
LSB
Bipolar
–J, –S
±10
LSB
–K, –L, –T, –U
±4
LSB
Full Scale (Gain) Error
±0.3
%FS
–J
±0.5
%FS
±0.22
%FS
–K
±0.4
%FS
±0.12
%FS
–L
±0.35
%FS
±0.05
%FS
–S
±0.8
%FS
±0.5
%FS
–T
±0.6
%FS
±0.25
%FS
–U
±0.4
%FS
±0.12
%FS
STABILITY
Unipolar Offset
–J
±10
ppm/°C
–K, –L, –S
±5
ppm/°C
–T, –U
±2.5
ppm/°C
Bipolar Offset
–J, –S
±10
ppm/°C
–K, –L, –T
±5
ppm/°C
–U
±2.5
ppm/°C
Gain (Scale Factor)
–J, –S
±50
ppm/°C
–K, –T
±25
ppm/°C
–L, –U
±10
ppm/°C
PSRR
VLOGIC
±0.5
LSB
VCC
–J, –S
±2
LSB
–K, –L, –T, –U
±1
LSB
POWER REQUIREMENTS
+4.5
+5.5
V
VLOGIC
ILOGIC
HS574A
1
3
mA
SP674A
1
3
mA
VCC
+11.4
+16.5
V
ICC
HS574A
7
9
mA
SP674A
7
9
mA
CONDITIONS
@ 25°C and TMIN to TMAX
@ 25°C and TMIN to TMAX
Note 2
@ 25°C
TMIN to TMAX
@ 25°C
TMIN to TMAX
Note3
% of full scale; TMIN to TMAX
Note 4
No adjustment @ 25°C
With adjustment @ 25°C
No adjustment @ 25°C
With adjustment @ 25°C
No adjustment @ 25°C
With adjustment @ 25°C
No adjustment @ 25°C
With adjustment @ 25°C
No adjustment @ 25°C
With adjustment @ 25°C
No adjustment @ 25°C
With adjustment @ 25°C
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
TMIN to TMAX
+4.5V ≤ VLOGIC ≤ +5.5V
Note 5
5
SPECIFICATIONS (continued)
(Typical @ 25°C with VCC = +15V, VEE = 0V, VLOGIC = +5V unless otherwise noted)
PARAMETER
Power Dissipation
HS574A
SP674A
ENVIRONMENTAL
Operating Temperature Range
–J, –K, –L
–S, –T, –U
Storage Temperature Range
–J, –K, –L
–A, –S, –T, –U
MIN.
TYP.
MAX.
110
110
150
150
UNIT
CONDITIONS
mW
mW
0
–55
+70
+125
°C
°C
–40
–65
+85
+150
°C
°C
Notes:
1.
Available for external loads. External load should not change during conversion. When supplying an
external load and operating on a +12V supply, a buffer amplifier must be provided for the reference
output.
2.
Minimum resolution for which no missing codes are guaranteed.
3.
Externally adjustable to zero. See Calibration information.
4.
Fixed 50Ω resistor between REF OUT and REF IN.
5.
+13.5V ≤ VCC ≤ +16.5V or +11.4V ≤ VCC ≤ +12.6V.
6.
Specifications are identical for all models unless otherwise noted.
PIN ASSIGNMENTS…
PIN
FUNCTION
PIN
FUNCTION
1
VLOGIC
28
STS
2
12/8
27
DB11(MSB)
3
CS
26
DB10
4
A0
25
DB9
5
R/C
24
DB8
6
CE
23
DB7
7
VCC
22
DB6
8
REF OUT
21
DB5
9
ANA GND(AC)
20
DB4
10
REF IN
19
DB3
11
N/C*
18
DB2
12
BIP OFF
17
DB1
13
10VIN
16
DB0(LSB)
14
20VIN
15
DIG. GND
*HS574A – This pin is not connected to the device; it
can be tied to –15V, ground, or left floating.
*SP674A – This pin is not connected to the device; VEE
is generated internally.
6
FEATURES…
The HS574A/SP674A feature standard bipolar
and unipolar input ranges of 10V and 20V. Input
ranges are controlled by a bipolar offset pin and
laser-trimmed for specified linearity, gain and
offset accuracy. Power requirements are +5V
and +12V to +15V with a maximum dissipation
of 150mW at the specified voltages. Conversion
times of 8µs, 10µs, 15µs and 25µs are available,
as are units with 10, 25 or 50ppm/°C temperature
coefficients for flexible matching to specific
application requirements.
the LSB at the beginning of the conversion cycle
to provide an output voltage from the CDAC that
is equal to the input signal voltage (which is
divided by the input voltage divider network).
The comparator determines whether the addition
of each successively–weighted bit voltage causes
the CDAC output voltage summation to be greater
or less than the input voltage; if the sum is less,
the bit is left on; if more, the bit is turned off.
After testing all the bits, the SAR contains a 12–
bit binary code which accurately represents the
input signal to within ±1⁄2 LSB.
The HS574A/SP674A are available in six product grades for each conversion time. The –J, –K
and –L models are specified over 0˚C to + 70˚C
commercial temperature range; the –S, –T and –
U models are specified over the –55˚C to +125˚C
military temperature range. Processing in accordance with MIL–STD–883C is also available.
The HS574A/SP674A are packaged in a 28–pin
CerDIP. Please consult the factory for other
packaging options.
The internal reference provides the voltage reference to the CDAC with excellent stability over
temperature and time. The reference is trimmed
to 10.00 Volts ±1% and can supply up to 2mA to
an external load in addition to that required to
drive the reference input resistor (1mA) and
offset resistor (1mA) when operating with ±15V
supplies. If the HS574A/SP674A is used with
±12V supplies, or if external current must be
supplied over the full temperature range, an
external buffer amplifier is recommended. Any
external load on the HS574A/SP674A reference
must remain constant during conversion.
CIRCUIT OPERATION…
The HS574A/SP674A are complete 12–bit analog-to-digital converters with integral voltage
reference, comparator, successive–approximation register (SAR), sample–and–hold, clock,
output buffers and control circuitry. The high
level of integration of the HS574A/SP674A
means they require few external components.
When the control section of the HS574A/SP674A
initiates a conversion command, the clock is
enabled and the successive–approximation register is reset to all zeros. Once the conversion
cycle begins, it can not be stopped or re–started
and data is not available from the output buffers.
The SAR, timed by the clock, sequences through
the conversion cycle and returns an end–of–
convert flag to the control section of the ADC.
The clock is then disabled by the control section,
the output status goes low, and the control section is enabled to allow the data to be read by
external command.
The internal HS574A/SP674A 12–bit CDAC is
sequenced by the SAR starting from the MSB to
The sample and hold is a default function by
virtue of the CDAC architecture. Therefore the
majority of the S/H specifications are included
within the A/D specifications.
Sample–and–Hold Function
Although there is no sample-and-hold circuit in
the classical sense, the sampling nature of the
capacitive DAC makes the HS574A/SP674A
appear to have a built in sample and hold. This
sample and hold action substantially increases
the usefulness of the HS574A/SP674A over that
of similar competing devices.
Note that even though the user may use an
external sample and hold for very high frequency inputs, the internal sample and hold still
provides a very useful isolation function. Once
the internal sample is taken by the CDAC capacitance, the input of the HS574A/SP674A is disconnected from the input. This prevents transients occurring during conversion from being
inflicted upon the attached buffer. All other 574/
674 circuits will cause a transient load current on
7
CE
∆VERROR = ∆t dv
dt
SAMPLE
POINT
R/C
t(ACQ)
ACQUISITION
TIME
∆VERROR
WAIT FOR
CONVERT SIGNAL
∆t
CONVERSION
WAIT FOR
BUS READ
VIN
CDAC VOLTAGE
0 VOLTS
ACQUISITION TIME =
APERTURE DELAY TIME =
0.12 x tCONVERT
Figure 1. Aperture Uncertainty
Figure 3. Sample–and–Hold Function
the input which will upset the buffer output and
may add error to the conversion itself.
acquisition of the input by the CDAC (this time
is defined as tACQ). Following these two cycles,
the input sample is taken and held. The A/D
conversion follows this cycle with the duration
controlled by the internal clock cycle, which is
determined by the specific product model. Note
that because the sample is taken relative to the
R/C transition, tACQ is also the traditional “aperture delay” of this internal sample and hold.
Since tACQ is measured in clock cycles, its
duration will vary with the internal clock
frequency. This results in TACQ = 2.9µ sec
±1.1µsecs between units and over temperatures.
Furthermore, the isolation of the input after the
acquisition time in the HS574A/SP674A allows
the user an opportunity to release the hold on an
external sample-and-hold and start it tracking
the next sample. This will increase system
throughput with the user's existing components.
When using an external S/H, the HS574A/
SP674A acts as any other 574–type device because the internal S/H is transparent. The sample/
hold function in the HS574A/SP674A is inherent to the capacitor DAC structure, and its timing
characteristics are determined by the internally
generated clock. However, for multiplexer operation, the internal S/H may eliminate the need
for an external S/H. The operation of the S/H
function is internal to the HS574A/SP674A and
is controlled through the normal R/C control line
(refer to Figure 3). When the R/C line makes a
negative transition, the HS574A/SP674A starts
the timing of the sampling and conversion. The
first two clock cycles are allocated to signal
25pF
REQ = 4KΩ at any range.
T = REQ x CEQ = 100ns.
Figure 2. Equivalent SP574A Input Circuit
8
Offset, gain and linearity errors of the S/H circuit, as well as the effects of its droop rate, are
included in the overall specs for the HS574A/
SP674A.
USING THE SPX74A SERIES
Typical Interface Circuit
The HS574A/SP674A is a complete A/D converter that is fully operational when powered up
and issued a Start Convert Signal. Only a few
external components are necessary. Figure 4
depicts a typical interface circuit for operating
the HS574A/SP674A in a unipolar input mode.
Figure 5 depicts a typical interface circuit for
operating the HS574A/SP674A in a bipolar input mode. Further information is given in the
following sections on these connections, but first
a few considerations concerning board layout to
achieve the best operation.
For each application of this device, strict attention must be given to power supply decoupling,
board layout (to reduce pickup between analog
OUTPUT BITS
MSB
12/8
CS
A0
R/C
27
26
25 24 23
22
21 20 19 18 17 16
LSB
2
NIBBLE A
3
CONTROL
LOGIC
4
5
NIBBLE B
NIBBLE C
THREE–STATE BUFFERS AND CONTROL
6
CE
12–BITS
OSCILLATOR
28
12–BIT SAR
R1
100K
+15V
ANALOG
INPUTS
STROBE
12–BITS
0 TO 10V 10V
IN 13
100K
STS
1
-15V
SAMPLE/HOLD
20V
IN 14
VLOGIC
+5V
1µF
CDAC
15
COMP
DGND
LSB
MSB
BIP
0 TO 20V OFF
12
100Ω
VREF
OUT
OFFSET/GAIN
TRIM NETWORK
REF
8
REF
AMP
R2
100Ω
10
VREF
IN
VCC 7
11
1µF
+15V
9
AGND
NO CONNNECTION
PERMITTED
Figure 4. Unipolar Input Connections
and digital sections), and grounding. Digital
timing, calibration and the analog signal source
must be considered for correct operation.
on the component side is recommended. Keep
analog signal traces away from digital lines. It is
best to lay the PC board out such that there is an
analog section and a digital section with a single
point ground connection between the two through
an RF bead. If this is not possible, run analog
To achieve specified accuracy, a double–sided
printed circuit board with a copper ground plane
OUTPUT BITS
MSB
12/8
CS
A0
R/C
CE
27
26
25
24
23
22
21 20 19 18
17 16
LSB
2
NIBBLE A
3
4
5
CONTROL
LOGIC
NIBBLE B
NIBBLE C
THREE–STATE BUFFERS AND CONTROL
6
12–BITS
OSCILLATOR
28
12–BIT SAR
1
ANALOG
INPUTS
12–BITS
±5V
10V
IN 13
SAMPLE/HOLD
±10V
20V
IN 14
MSB
+5V
1µF
STROBE
CDAC
STS
VLOGIC
COMP
15
DGND
LSB
BIP
OFF 12
100Ω
R1
VREF
OUT 8
100Ω
R2
OFFSET/GAIN
TRIM NETWORK
REF
REF
AMP
10
VREF
IN
VCC 7
11
1µF
+15V
9
AGND
NO CONNECTION
PERMITTED
Figure 5. Bipolar Input Connections
9
signals between ground traces and cross digital
lines at right angles only.
7) and analog common (pin 9) is sufficient. VEE
is generated internally so pin 11 may be grounded
or connected to a negative supply if the SPx74A
is being used to upgrade an already existing
design.
Grounding Considerations
Any ground path from the analog and digital
ground should be as low resistance as possible to
accommodate the ground currents present with
this device.
CALIBRATION AND CONNECTION
PROCEDURES
Unipolar
The calibration procedure consists of adjusting
the converter’s most negative output to its ideal
value for offset adjustment, and then adjusting
the most positive output to its ideal value for gain
adjustment.
The analog ground current is approximately 6mA
DC while the digital ground is 3mA DC. The
analog and digital common pins should be tied
together as close to the package as possible to
guarantee best performance. The code–dependent currents flow through the VLOGIC and VCC
terminals and not through the analog and digital
common pins.
Starting with offset adjustment and referring to
Figure 4, the midpoint of the first LSB increment
should be positioned at the origin to get an output
code of all 0s. To do this, an input of +1⁄2 LSB or
+1.22mV for the 10V range and +2.44mV for the
20V range should be applied to the SPx74A.
Adjust the offset potentiometer R1 for code transition flickers between 0000 0000 0000 and
0000 0000 0001.
Power Supplies
The supply voltages for the SPx74A must be
kept as quiet as possible from noise pickup and
also regulated from transients or drops. Because
the part has 12–bit accuracy, voltage spikes on
the supply lines can cause several LSB deviations on the output. Switching power supply
noise can be a problem. Careful filtering and
shielding should be employed to prevent the
noise from being picked up by the converter.
The gain adjustment should be done at positive
full scale. The ideal input corresponding to the
last code change is applied. This is 11⁄2LSB
below the nominal full scale which is +9.9963V
for the 10V range and +19.9927V for the 20V
range. Adjust the gain potentiometer R2 for flicker
between codes 1111 1111 1110 and 1111 1111
1111. If calibration is not necessary for the
intended application, replace R2 with a 50Ω, 1%
metal film resistor and remove the network ana-
Capacitor bypass pairs are needed from each
supply pin to its respective ground to filter noise
and counter the problems caused by the variations in supply current. A 10µF tantalum and a
0.1µF ceramic type in parallel between VLOGIC
(pin 1) and digital common (pin15), and VCC (pin
NIBBLE B ZERO
OVERRIDE
NIBBLE A, B
INPUT BUFFERS
NIBBLE C
12/8
READ CONTROL
CS
A0
R/C
H
CE
EOC8
CK
Q
D
Q
A0 LATCH
EOC12
Figure 6. SPx74A Control Logic
10
D Q
CK
R
DELAY
STS
log input to pin 13 for the 0V to 10V range or to
pin 14 for the 0V to 20V range.
Bipolar
The gain and offset errors listed in the specifications may be adjusted to zero using the potentiometers R1 and R2 (See Figure 5). If adjustment
is not needed, either or both pots may be replaced
by a 50Ω, 1% metal film resistor.
To calibrate, connect the analog input signal to
pin 13 for a ±5V range or to pin 14 for a ±10V
range. First apply a DC input voltage 1⁄2 LSB
above negative full scale which is –4.9988V for
the ±5V range or –9.9976V for the ±10V range.
Adjust the offset potentiometer R1 for flicker
between output codes 0000 0000 0000 and 0000
0000 0001. Next, apply a DC input voltage 11⁄2
LSB below positive full scale which is +4.9963V
for the ±5 range or +9.9927V for the ±10V range.
Adjust the gain potentiometer R2 for flicker
between codes 1111 1111 1110 and 1111 1111
1111.
Alternative
The 100Ω potentiometer R2 provides gain adjust
for 10V and 20V ranges. In some applications, a
full scale of 10.24V (for and LSB of 2.5mV) or
20.48 (for an LSB of 5.0mV) is more convenient.
For these, replace R2 by a 50Ω, 1% metal film
resistor. Then to provide gain adjust for the 10.24
range, add a 200Ω potentiometer and a 95Ω
fixed resistor, all in series with pin 13. For the
20.48V range, add a 500Ω potentiometer and a
200Ω fixed resistor in series with pin 14.
CONTROLLING THE SPx74A
The SPx74A can be operated by most microprocessor systems due to the control input pins and
on–chip logic. It may also be operated in the
“stand–alone” mode and enabled by the R/C
input pin. Full microprocessor control consists
of selecting an 8– or 12–bit conversion cycle,
initiating the conversion, and reading the output
data when ready. The output read has the options
of choosing either 12–bits at once or 8–bits
followed by 4–bits in a left–justified format. All
five control inputs are TTL/CMOS compatible
and include 12/8, CS, A0, R/C and CE. The use
of these inputs in controlling the converter’s
operation is shown in Table 1, and the internal
control logic is shown in a simplified schematic
in Figure 6.
Conversion Start
A conversion may be initiated by a logic transition on any of the three inputs: CE, CS R/C, as
shown in Table 1. The last of the three to reach
the correct state starts the conversion, so one,
two or all three may be dynamically controlled.
The nominal delay from each is the same and all
three may change state simultaneously. In order
to assure that a particular input controls the start
of conversion, the other two should be setup at
least 50ns earlier. Refer to the convert mode
timing specifications. The Convert Mode timing
diagram is shown in Figure 8.
The output signal STS is the status flag and goes
high only when a conversion is in progress.
While STS is high, the output buffers remain in
a high impedance state so that data can not be
read. Also, when STS is high, an additional Start
Convert will not reset the converter or reinitiate
a conversion. Note, if A0 changes state after a
conversion begins, an additional Start Convert
command will latch the new state of A0 and
possibly cause a wrong cycle length for that
conversion (8–versus 12–bits).
CE CS R/C 12/8 A0
OPERATION
0
x
x
x
x
None
x
1
x
x
x
None
0
0
x
0
Initiate 12–Bit Conversion
0
0
x
1
Initiate 8–Bit Conversion
1
0
x
0
Initiate 12–Bit Conversion
1
0
x
1
Initiate 8–Bit Conversion
1
0
x
0
Initiate 12–Bit Conversion
1
0
x
1
Initiate 8–Bit Conversion
1
0
1
1
x
Enable 12–Bit Output
1
0
1
0
0
Enable 8 MSB's Only
1
0
1
0
1
Enable 4 LSB's plus 4
Trailing Zeroes
Table 1. SPx74A Control Input Truth Table
11
Conversion Length
A conversion start transition latches the state of
A0 as shown in Figure 8 and Table 1. The latched
state determines if the conversion stops with 8–
bits (A0 high) or continues for 12–bits (A0 low).
If all 12–bits are read following an 8–bit conversion, the three LSB’s will be a logic “0” and DB3
will be a logic “1”. A0 is latched because it is also
involved in enabling the output buffers as explained elsewhere. No other control inputs are
latched.
Stand–Alone Operation
The simplest interface is a control line connected
to R/C. The other controls must be tied to known
states as follows: CE and 12/8 are wired high, A0
and CS are wired low. The output data arrives in
words of 12–bits each. The limits on R/C duty
cycle are shown in Figures 9 and 10. The duty
cycle may be within and including the extremes
shown in the specifications. In general, data may
be read when R/C is high unless STS is also high,
indicating a conversion is in progress.
Reading Output Data
The output data buffers remain in a high impedance state until the following four conditions are
met: R/C is high, STS is low, CE is high and CS
is low. The data lines become active in response
to these four conditions, and output data according to the conditions of the control lines 12/8 and
A0. The timing diagram for this process is shown
in Figure 11. When 12/8 is high, all 12 data
outputs become active simultaneously and the
A0 input is ignored. The 12/8 input is usually tied
high or low; it is TTL/CMOS compatible. When
12/8 is low, the output is separated into two 8–bit
bytes as shown below:
4 through 7 are forced to a zero and the four
LSB’s are enabled. The two byte format is “left
justified data” as shown above and can be considered to have a decimal point or binary to the
left of byte 1.
A0 may be toggled without damage to the converter at any time. Break–before–make action is
guaranteed between the two data bytes. This
assures that the outputs which are strapped together in Figure 11 will never be enabled at the
same time.
In Figure 11, it can be seen that a read operation
usually begins after the conversion is complete
and STS is low. If earlier access is needed, the
read can begin no later than the addition of times
tDD and tHS before STS goes low.
A0
ADDRESS BUS
STS
2
12/8
DB11 (MSB)
4
28
27
26
A0
25
24
BYTE 1
xxxx xxxx
BYTE2
xxxx 0000
MSB
LSB
23
DATA
BUS
22
SPx74A
21
20
19
18
This configuration makes it easy to connect to an
8–bit address bus as shown in Figure 7. The A0
control can be connected to the least significant
bit of the data bus in order to store the output data
into two consecutive memory locations. When
A0 is pulled low, the 8 MSB’s are enabled only.
When A0 is high, the 8 MSB’s are disabled, bits
12
17
DB0 (LSB)
DIG
COM
16
15
Figure 7. Interfacing SPx74A to 8–Bit Interface Bus
CONVERT MODE TIMING
tHEC
CE
tSSC
CS
tSRC
R/C
tHRC
A0
tSAC
tHAC
STS
tDSC
tC
HIGH IMPEDANCE
DB11–
DB0
CHARACTERISTICS
Typical @ 25˚C, VCC = +15V or +10V, VLOGIC = +5V, VEE = 0V, unless otherwise specified.
PARAMETER
tDSC STS Delay from CE
MIN.
TYP.
MAX.
200
UNITS
ns
tHEC CE Pulse Width
50
tSSC CS to CE Setup
50
ns
tHSC CS Low during CE High
50
ns
ns
tSRC R/C to CE Setup
50
ns
tHRC R/C Low during CE High
50
ns
tSAC A0 to CE Setup
0
ns
tHAC A0 Valid during CE High
50
tC
NOTES:
1.
2.
3.
4.
Conversion Time1, 3, 4
CONDITIONS
ns
See specifications
Parameters guaranteed by design and sample tested.
Parameters 100% tested @ 25˚C on special orders.
100% tested.
TMIN to TMAX.
Figure 8. Convert Mode Timing
13
STAND–ALONE MODE TIMING CHARACTERISTICS
Typical @ 25˚C, VCC= +15V or +12V, VLOGIC = +5V, VEE =0V, unless otherwise specified.
PARAMETER
tHRL Low R/C Pulse Width 2
tDS
MIN.
50
TYP.
UNITS
ns
200
ns
1000
ns
STS Delay from R/C 2
tHDR Data Valid After R/C Low 2
tHS
MAX.
25
STS Delay After Data Valid 2
tHRH High R/C Pulse Width
CONDITIONS
ns
300
150
ns
tDDR Data Access Time
150
ns
NOTES:
1. Parameters guaranteed by design and sample tested.
2. Parameters 100% tested @ 25˚C on special orders.
tHRL
R/C
tDS
tC
STS
tHDR
tHS
DB11–DB0
DATA VALID
DATA VALID
Figure 9. Low Pulse for R/C — Outputs Enabled After Conversion
R/C
tHRH
tDS
tC
STS
tDDR
DB11–DB0
HIGH–Z
tHDR
DATA VALID
HIGH–Z
Figure 10. High Pulse For R/C — Outputs Enabled While R/C is High, Otherwise High Impedance
14
READ MODE TIMING
CE
CS
tSSR
tHSR
tHRR
R/C
tSRR
A0
tSAR
tHAR
STS
tHD
HIGH
DB11–
DB0
IMPEDANCE
DATA
VALID
tDD
tHL
CHARACTERISTICS
Typical @ 25˚C, VCC = +15V or +12V, VLOGIC = +5V, VEE = 0V, unless otherwise specified.
tDD
PARAMETER
Access Time From CE2
tHD
Data Valid After CE Low2
tHL
Output Float Delay2
tSSR CS to CE Setup
MIN.
TYP.
MAX.
150
UNITS
ns
150
ns
25
ns
50
0
ns
tSRR R/C to CE Setup
0
0
ns
tSAR A0 to CE Setup
50
tHSR CS Valid After CE Low
0
0
ns
tHRR R/C High After CE Low
0
50
ns
tHAR A0 Valid After CE Low
50
tHS
300
STS Delay After Data Valid
CONDITIONS
ns
ns
1000
ns
NOTES:
1.
Parameters guaranteed by design and sample tested.
2.
Parameters 100% tested @ 25˚C on special orders.
Figure 11. Read Mode Timing
15
ORDERING INFORMATION
Model .................... No Missing Codes to; ... Linearity ...................... Gain TC ......................... Temperature Range ............ Package Type
25µs Conversion Time
HS574AA .............. 11 Bits .............................. ±1.0 LSB ...................... 50ppm/°C .............. –40°C to +85°C ............ 28–pin, 0.6" Ceramic DIP
HS574AB .............. 12 Bits .............................. ±0.5 LSB ...................... 27ppm/°C .............. –40°C to +85°C ............ 28–pin, 0.6" Ceramic DIP
HS574AC .............. 12 Bits .............................. ±0.5 LSB ...................... 10ppm/°C .............. –40°C to +85°C ............ 28–pin, 0.6" Ceramic DIP
HS574AJ ............... 11 Bits .............................. ±1.0 LSB ...................... 50ppm/°C .............. 0°C to +70°C ................ 28–pin, 0.6" Ceramic DIP
HS574AK .............. 12 Bits .............................. ±0.5 LSB ...................... 27ppm/°C .............. 0°C to +70°C ................ 28–pin, 0.6" Ceramic DIP
HS574AL .............. 12 Bits .............................. ±0.5 LSB ...................... 10ppm/°C .............. 0°C to +70°C ................ 28–pin, 0.6" Ceramic DIP
HS574AS .............. 11 Bits .............................. ±1.0 LSB ...................... 50ppm/°C .............. –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
HS574AT .............. 12 Bits .............................. ±0.5 LSB ...................... 25ppm/°C .............. –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
HS574AU .............. 12 Bits .............................. ±0.5 LSB ...................... 12.5ppm/°C ........... –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
HS574AS/883* ...... 11 Bits .............................. ±1.0 LSB ...................... 50ppm/°C .............. –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
HS574AT/883* ...... 12 Bits .............................. ±0.5 LSB ...................... 25ppm/°C .............. –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
HS574AU/883* ..... 12 Bits .............................. ±0.5 LSB ...................... 12.5ppm/°C ........... –55°C to +125°C .......... 28–pin, 0.6" Ceramic DIP
15µs Conversion Time
SP674AA .............. 11 Bits .............................. ±1.0
SP674AB .............. 12 Bits .............................. ±0.5
SP674AC .............. 12 Bits .............................. ±0.5
SP674AJ ............... 11 Bits .............................. ±1.0
SP674AK .............. 12 Bits .............................. ±0.5
SP674AL ............... 12 Bits .............................. ±0.5
SP674AS .............. 11 Bits .............................. ±1.0
SP674AT ............... 12 Bits .............................. ±0.5
SP674AU .............. 12 Bits .............................. ±0.5
SP674AS/883* ...... 11 Bits .............................. ±1.0
SP674AT/883* ...... 12 Bits .............................. ±0.5
SP674AU/883* ...... 12 Bits .............................. ±0.5
LSB ...................... 50ppm/°C ..............
LSB ...................... 27ppm/°C ..............
LSB ...................... 10ppm/°C ..............
LSB ...................... 50ppm/°C ..............
LSB ...................... 27ppm/°C ..............
LSB ...................... 10ppm/°C ..............
LSB ...................... 50ppm/°C ..............
LSB ...................... 25ppm/°C ..............
LSB ...................... 12.5ppm/°C ...........
LSB ...................... 50ppm/°C ..............
LSB ...................... 25ppm/°C ..............
LSB ...................... 12.5ppm/°C ...........
–40°C to +85°C ............
–40°C to +85°C ............
–40°C to +85°C ............
0°C to +70°C ................
0°C to +70°C ................
0°C to +70°C ................
–55°C to +125°C ..........
–55°C to +125°C ..........
–55°C to +125°C ..........
–55°C to +125°C ..........
–55°C to +125°C ..........
–55°C to +125°C ..........
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
28–pin,
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
0.6"
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
DIP
DIP
DIP
DIP
DIP
DIP
DIP
DIP
DIP
DIP
DIP
DIP
* MIL–STD–883C processing.
NOTE: Electrical specifications for –AA, –AB and –AC grades are the same as –AJ, –AK, and –AL models respectively, with the exception of
extended operating temperature range performance from –40°C to +85°C.
Please consult the factory for other packaging options.
16