ADADC84_15 Datasheet, PDF (1/12 Pages) Analog Devices – FAST COMPLETE 12 BIT A/D CONVERTERS

FEATURES
PERFORMANCE
Complete 12-bit A/D converter with reference and clock
Fast successive approximation conversion: 10 µs or 5 µs
Buried Zener reference for long-term stability and low
Gain TC: 10 ppm/°C
Max nonlinearity: < ±0.012%
Low power: 880 mW typ
Low chip count—high reliability
Industry-standard pinout
Z models for ±12 V operation available
MIL-STD-883B processing available
VERSATILITY
Negative true parallel logic outputs
Short cycle capability
Precision +6.3 V reference for external applications
PRODUCT DESCRIPTION
The AD ADC84/AD ADC85 series devices are high speed, low cost
12-bit successive approximation analog-to-digital converters that
include an internal clock, reference, and comparator. Its hybrid IC
design utilizes MSI digital and linear monolithic chips in
conjunction with a 12-bit monolithic DAC to provide modular
performance and versatility with IC size, price, and reliability.
Important performance characteristics of the AD ADC84/
AD ADC85 series include maximum linearity error of ±0.012%;
gain TC below 15 ppm/°C at 25°C; typical power dissipation of
880 mW; and conversion time of less than 10 µs for the 12-bit
versions. Of considerable significance in severe and aerospace
applications is the guaranteed performance from –55°C to +125°C
of the AD ADC85S, which is also available with environmental
screening. Monotonic operation of the feedback DAC guarantees
no missing codes over temperature ranges of 0°C to +70°C, –25°C
to +85°C, and –55°C to +125°C.
The design of the AD ADC84/AD ADC85 includes scaling resistors
that provide analog input signal ranges of ±2.5 V, ±5 V, ±10 V, 0 V to
+5 V, or 0 V to +10 V. The 6.3 V precision reference, which can be
used for external applications, and the input buffer amplifier add
flexibility and value. All digital signals are fully DTL and TTL
compatible, and the data output is negative-true and available in
parallel form.
The AD ADC84/AD ADC85 are available in a performance grade
specified for 12-bit accuracy (±0.012% FSR max) with 10 µs
maximum conversion time.
Rev. B
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Fast, Complete
12-Bit A/D Converters
AD ADC84/AD ADC85
Figure 1. Functional Block Diagram
The AD ADC84 and AD ADC85C are specified for operation over
the 0°C to +70°C temperature range. The AD ADC85 and
AD ADC85S are specified for the –25°C to +85°C and –55°C to
+125°C ranges, respectively. The serial output function is no longer
supported on the AD ADC84/AD ADC85 after date code 9623.
PRODUCT HIGHLIGHTS
1. The AD ADC84/ AD ADC85 series devices are complete
12-bit ADCs. No external components are required to perform
a conversion.
2. The AD ADC84/ AD ADC85 directly replaces other devices of
this type with significant increases in performance.
3. The fast conversion rates of the AD ADC84 and AD ADC85
(10 μs) make them an excellent choice for applications
requiring high system throughput rates.
4. The internal buried Zener reference is laser trimmed to 6.3 V
±0.1% and ±10 ppm/°C typical TC. The reference is available
externally and can provide up to 1 mA.
5. The integrated package construction provides high quality and
reliability with small size and weight.
6. The monolithic 12-bit feedback DAC is used for reduced chip
count and higher reliability.
7. The AD ADC85S/883B comes processed to MIL-STD-883,
Class B requirements.
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