FUNCTIONAL BLOCK DIAGRAM CONTROL INPUTS
I2L CONTROL LOGIC LSB
DIGITAL INPUT DATA (BUS) DB2
FEATURES Complete 8-Bit DAC Voltage Output–2 Calibrated Ranges Internal Precision Bandgap Reference Single-Supply Operation: +5 V to +15 V Full Microprocessor Interface Fast: 1 s Voltage Settling to ؎1/2 LSB Low Power: 75 mW No User Trims Guaranteed Monotonic Over Temperature All Errors Specified TMIN to TMAX Small 16-Pin DIP and 20-Pin PLCC Packages Single Laser-Wafer-Trimmed Chip for Hybrids Low Cost MIL-STD-883 Compliant Versions Available
DACPORT Low Cost, Complete µP-Compatible 8-Bit DAC AD558* MSB
I2L LATCHES MSB 8-BIT VOLTAGE-SWITCHING D-TO-A CONVERTER
OUTPUT AMP VOUT VOUTSENSE A
BAND GAP REFERENCE
The AD558 DACPORT® is a complete voltage-output 8-bit digital-to-analog converter, including output amplifier, full microprocessor interface and precision voltage reference on a single monolithic chip. No external components or trims are required to interface, with full accuracy, an 8-bit data bus to an analog system.
1. The 8-bit I2L input register and fully microprocessorcompatible control logic allow the AD558 to be directly connected to 8- or 16-bit data buses and operated with standard control signals. The latch may be disabled for direct DAC interfacing.
The performance and versatility of the DACPORT is a result of several recently-developed monolithic bipolar technologies. The complete microprocessor interface and control logic is implemented with integrated injection logic (I2L), an extremely dense and low power logic structure that is process-compatible with linear bipolar fabrication. The internal precision voltage reference is the patented low voltage bandgap circuit which permits fullaccuracy performance on a single +5 V to +15 V power supply. Thin-film silicon-chromium resistors provide the stability required for guaranteed monotonic operation over the entire operating temperature range (all grades), while recent advances in laser-wafer-trimming of these thin-film resistors permit absolute calibration at the factory to within ± 1 LSB; thus no user-trims for gain or offset are required. A new circuit design provides voltage settling to ± 1/2 LSB for a full-scale step in 800 ns. The AD558 is available in four performance grades. The AD558J and K are specified for use over the 0°C to +70°C temperature range, while the AD558S and T grades are specified for –55°C to +125°C operation. The “J” and “K” grades are available either in 16-pin plastic (N) or hermetic ceramic (D) DIPS. They are also available in 20-pin JEDEC standard PLCC packages. The “S” and “T” grades are available in the 16-pin hermetic ceramic DIP package. *Protected by U.S. Patent Nos. 3,887,863; 3,685,045; 4,323,795; Patents Pending. DACPORT is a registered trademark of Analog Devices, Inc.
2. The laser-trimmed on-chip SiCr thin-film resistors are calibrated for absolute accuracy and linearity at the factory. Therefore, no user trims are necessary for full rated accuracy over the operating temperature range. 3. The inclusion of a precision low voltage bandgap reference eliminates the need to specify and apply a separate reference source. 4. The voltage switching structure of the AD558 DAC section along with a high speed output amplifier and laser trimmed resistors give the user a choice of 0 V to +2.56 V or 0 V to +10 V output ranges, selectable by pin-strapping. Circuitry is internally compensated for minimum settling time on both ranges; typically settling to ± 1/2 LSB for a full-scale 2.55 volt step in 800 ns. 5. The AD558 is designed and specified to operate from a single +4.5 V to +16.5 V power supply. 6. Low digital input currents, 100 µA max, minimize bus loading. Input thresholds are TTL/low voltage CMOS compatible over the entire operating VCC range. 7. All AD558 grades are available in chip form with guaranteed specifications from +25°C to TMAX. MIL-STD-883, Class B visual inspection is standard on Analog Devices bipolar chips. Contact the factory for additional chip information.
8. The AD558 is available in versions compliant with MILSTD-883. Refer to Analog Devices Military Products Databook or current AD558/883B data sheet for detailed specifications.
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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