|
|
PDF ML2283CIP Data sheet ( Hoja de datos )
| Número de pieza | ML2283CIP | |
| Descripción | Serial I/O 8-Bit A/D Converters | |
| Fabricantes | Micro Linear | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de ML2283CIP (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
|
No Preview Available !
May 1997
ML2280*, ML2283**
Serial I/O 8-Bit A/D Converters
GENERAL DESCRIPTION
The ML2280 and ML2283 are 8-bit successive
approximation A/D converters with serial I/O and
configurable input multiplexers with up to 4 input
channels.
All errors of the sample-and-hold incorporated on the
ML2280 and ML2283 are accounted for in the analog-to-
digital converters accuracy specification.
The voltage reference can be externally set to any value
between GND and VCC, thus allowing a full conversion
over a relatively small voltage span if desired.
The ML2283 is an enhanced double polysilicon, CMOS,
pin-compatible second source for the ADC0833 A/D
converter. All parameters are guaranteed over temperature
with a power supply voltage of 5V ±10%.
BLOCK DIAGRAM
ML2281
CONTROL
AND
TIMING
OUTPUT
SHIFT-REGISTER
CS
CLK
DO
FEATURES
s Conversion time: 6µs
s ML2280 capable of digitizing a 5V, 40kHz sine wave
s Total unadjusted error with external
reference: ±1/2LSB or ±1LSB
s Sample-and-hold: 375ns acquisition
s 0 to 5V analog input range with single 5V
power supply
s 2.5V reference provides 0 to 5V analog input range
s No zero- or full-scale adjust required
s Low power: 12.5mW MAX
s Analog input protection: 25mA (min) per input
s Differential analog voltage inputs (ML2280)
s Programmable multiplexer with differential or single
ended analog inputs (ML2283)
s 0.3" width 8- or 14-pin DIP, or 8-Pin SOIC (ML2280)
s Superior pin-compatible replacement for ADC0833
* This Part Is Obsolete
** This Part Is End Of Life As Of August 1, 2000
ML2283
4-BIT
INPUT
SHIFT-REGISTER
CONTROL
AND
TIMING
DI
SARS
CLK
CS
VIN+
A/D WITH SAMPLE & HOLD FUNCTION
+Σ
–
8pF
+
COMP
–
SUCCESSIVE
APPROXIMATION
REGISTER
VIN–
8pF
D/A
CONVERTER
VREF/2
VCC GND
CH0
4-CHANNEL
CH1
S.E.
OR
2-CHANNEL
CH2
DIFF
MULTIPLEXER
CH3
OUTPUT
SHIFT-REGISTER
DO
SE
A/D
CONVERTER
WITH
SAMPLE & HOLD
FUNCTION
AGND VREF/2
VCC
DGND
SHUNT
REGULATOR
V+
1
1 page  
ML2280, ML2283
ELECTRICAL CHARACTERISTICS (Continued)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
NOTE 3
MAX
UNITS
AC ELECTRICAL CHARACTERISTICS
fCLK
tACQ
tC
SNR
THD
Clock Frequency
(Note 4)
Sample-and-Hold Acquisition
Conversion Time
Not including MUX adddressing time
Signal to Noise Ratio
ML2280
Total Harmonic Distortion
ML2280
VIN = 40kHz, 5V sine. fCLK = 1.333MHz
(fSAMPLING @ 120kHz). Noise is sum of all
nonfundamental components up to 1/2
of fSAMPLING (Note 11)
VIN = 40kHz, 5V sine. fCLK = 1.333MHz
(fSAMPLING @ 120kHz). THD is sum of 2,
3, 4, 5 harmonics relative to fundamental
(Note 11)
10
1333
kHz
1/2 1/fCLK
8 1/fCLK
47 dB
–60 dB
IMD
Intermodulation Distortion
ML2280
VIN = fA + fB. fA = 40kHz, 2.5V sine.
fB = 39.8kHz, 2.5V Sine, fCLK = 1.333MHz
(fSAMPLING @ 120kHz). IMD is (fA + fB),
(fA – fB), (2fA + fB), (2fA – fB), (fA + 2fB),
(fA – 2fB) relative to fundamental (Note 11)
–60
Clock Duty Cycle
(Notes 4, 9)
40 60
dB
%
tSET-UP
CS Falling Edge or Data Input (Note 4)
Valid to CLK Rising Edge
130 ns
tHOLD
Data Input Valid after
CLK Rising Edge
(Note 4)
80 ns
tPD1,
tPD0
CLK Falling Edge to Output
Data Valid
CL = 100pF (Note 4 & 10)
Data MSB first
Data LSB first
90 200 ns
50 110 ns
t1H,
Rising Edge of CS to Data
CL = 10pF, RL = 10kW (see high impedance
t0H Output and SARS Hi-Z
test circuits) (Note 5)
40 90 ns
CL = 100pF, RL = 2kW (Note 5)
80 160 ns
CIN Capacitance of Logic Input
5 pF
COUT Capacitance of Logic Outputs
5 pF
Note 1: When the input voltage (VIN) at any pin exceeds the power supply rails (VIN < GND < or VIN > VCC) the absolute value of current at that pin should be limited to
25mA or less.
Note 2: 0°C to 70°C and –40°C to 85°C operating temperature range devices are 100% tested with temperature limits guaranteed by 100% testing, sampling, or by
correlation with worst-case test conditions.
Note 3: Typicals are parametric norm at 25°C.
Note 4: Parameter guaranteed and 100% tested.
Note 5: Parameter guaranteed. Parameters not 100% tested are not in outgoing quality level calculation.
Note 6: Total unadjusted error includes offset, full-scale, linearity, multiplexer and sample-and-hold errors.
Note 7:
For VIN– • VIN+ the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input (see Block Diagram) which will forward conduct for
analog input voltages one diode drop below ground or one diode drop greater than the VCC supply. Be careful, during testing at low VCC 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. The spec allows
50mV forward bias of either diode. This means that as long as the analog VIN or VREF does not exceed the supply voltage by more than 50mV, the output code will
be correct. To achieve an absolute 0V to 5V input voltage range will therefore require a minimum supply voltage of 4.950VDC over temperature variations, initial
tolerance and loading.
Note 8: Leakage current is measured with the clock not switching.
Note 9: A 40% to 60% clock duty cycle range insures proper operation at all clock frequencies. In the case that an available clock has a duty cycle outside of these limits,
the minimum time the clock is high or the minimum time the clock is low must be at least 300ns. The maximum time the clock can be high or low is 60µs.
Note 10: Since data, MSB first, is the output of the comparator used in the successive approximation loop, an additional delay is built in (see Block Diagram) to allow for
comparator response time..
Note 11: Because of multiplexer addressing, test conditions for the ML2283 is VIN = 30kHz, 5V sine (fSAMPLING ª 89kHz)
5
5 Page 
When the start bit has been shifted into the start location
of the MUX register, the input channel has been assigned
and a conversion is about to begin. An interval of 1/2
clock period is used for sample & hold settling through the
selected MUX channels. The SAR status output goes high
at this time to signal that a conversion is now in progress
and the DI input is ignored.
The DO output comes out of High impedance and
provides a leading zero for this one clock period.
When the conversion begins, the output of the
comparator, which indicates whether the analog input is
greater than or less than each successive voltage from the
internal DAC, appears at the DO output on each falling
edge of the clock. This data is the result of the conversion
being shifted out (with MSB coming first) and can be read
by external logic or µP immediately.
After 8 clock periods, the conversion is completed. The SAR
status line returns low to indicate this 1/2 clock cycle later.
The serial data is always shifted out MSB first during the
conversion. After the conversion has been completed, the
data can be shifted out a second time with LSB first. The
2280 data is shifted out only once, MSB first.
All internal registers are cleared when the CS input is
high. If another conversion is desired, CS must make a
high to low transition followed by address information.
The DI input and DO output can be tied together and
controlled through a bidirectional µP I/O bit with one
connection. This is possible because the DI input is only
latched in during the MUX addressing interval while the
DO output is still in the high impedance state.
ML2280, ML2283
REFERENCE
The ML2280 and ML2283 are intended primarily for use in
circuits requiring absolute accuracy. In this type of system,
the analog inputs vary between very specific voltage limits
and the reference voltage for the A/D converter must remain
stable with time and temperature. For ratiometric
applications, see the ML2281 and ML2284 which have a
VREF input that can be tied to VCC.
The voltage applied to the VREF/2 pin defines the voltage
span of the analog input (the difference between VIN+ and
VIN–) over which the 256 possible output codes apply. A
full-scale conversion (an all 1s output code) will result when
the voltage difference between a selected “+”input and “–”
input is approximately twice the voltage at the VREF/2 pin.
This internal gain of 2 from the applied reference to the full-
scale input voltage allows biasing a low voltage reference
diode from the 5VDC converter supply. To accommodate a
5V input span, only a 2.5V reference is required. The output
code changes in accordance with the following equation:
Output
Code
=
256
VIN2((+V)R−EFV/I2N)(−)
where the output code is the decimal equivalent of the 8-bit
binary output (ranging from 0 to 255) and the term VREF/2 is
the voltage to ground.
The VREF/2 pin is the center point of a two resistor divider
(each resistor is 10kW) connected from VCC to ground. Total
ladder input resistance is the parallel combination of these
two equal resist. As show in Figure 8, a reference diode
requiring an external biasing resistor if its current
requirements meet the indicated level.
The minimum value of VREF/2 can be quite small (See
Typical Performance Curves) to allow direct conversions of
transducer outputs providing less than a 5V output span.
Particular care must be taken with regard to noise pickup,
circuit layout and system error voltage sources when
operating with a reduced span due to the increased
sensitivity of the converter (1LSB equals VREF/256).
VCC
5V
VCC
5V
ML2280
ML2283
10kΩ
10kΩ
VREF/2
IZ
1.2V
+
VZ
ML2280
ML2283
10kΩ
10kΩ
VREF/2
2.5V
GND
–
GND
VFULL-SCALE ≅ 2.4V
VFULL-SCALE ≅ 5.0V
NOTE:
NO
EXTERNAL
BIASING
RESISTOR
NEENED
IF: VZ
<
VCC
2
AND IZ min. <
VCC/2 – VZ
5kΩ
Figure 8. Reference Biasing
11
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet ML2283CIP.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| ML2283CIP | Serial I/O 8-Bit A/D Converters | Micro Linear |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |