DACPORT, Low-Cost Complete mP-Compatible 8-Bit DAC AD557

FEATURES

• Complete 8-Bit DAC
• Voltage Output—0 V to 2.56 V
• Internal Precision Band-Gap Reference
• Single-Supply Operation: +5 V (610%)
• Full Microprocessor Interface
• Fast: 1 ms Voltage Settling to 61/2 LSB
• Low Power: 75 mW
• No User Trims Required
• Guaranteed Monotonic Over Temperature
• All Errors Specified TMIN to TMAX
• Small 16-Pin DIP or 20-Pin PLCC Package
• Low Cost

GENERAL DESCRIPTION

The AD557 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.

The low cost and versatility of the AD557 DACPORT are the result of continued development in monolithic bipolar technologies.

The complete microprocessor interface and control logic is implemented with integrated injection logic (I2 L), 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 band-gap circuit which permits full-accuracy performance on a single +5 V power supply. Thin-film silicon-chromium resistors provide the stability required for guaranteed monotonic operation over the entire operating temperature range, while laser-wafer trimming of these thin-film resistors permits absolute calibration at the factory to within ±2.5 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 AD557 is available in two package configurations. The AD557JN is packaged in a 16-pin plastic, 0.3"-wide DIP. For surface mount applications, the AD557JP is packaged in a 20-pin JEDEC standard PLCC. Both versions are specified over the operating temperature range of 0°C to +70°C.

PRODUCT HIGHLIGHTS

1. The 8-bit I2 L input register and fully microprocessorcompatible control logic allow the AD557 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.

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 band-gap reference eliminates the need to specify and apply a separate reference source.

4. The AD557 is designed and specified to operate from a single +4.5 V to +5.5 V power supply.

5. Low digital input currents, 100 µA max, minimize bus loading. Input thresholds are TTL/low voltage CMOS compatible.

6. The single-chip, low power I2 L design of the AD557 is inherently more reliable than hybrid multichip or conventional single-chip bipolar designs.

ABSOLUTE MAXIMUM RATINGS*

V_CC to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to +18 V

Digital Inputs (Pins 1–10) . . . . . . . . . . . . . . . . . .0 V to +7.0 V

V_OUT . . . . . . . . . . . . . . . . . . . . . . . Indefinite Short to Ground Momentary Short to VCC

Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . .450 mW

Storage Temperature Range

N/P (Plastic) Packages . . . . . . . . . . . . . . . .–25°C to +100°C

Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . . 300°C

Thermal Resistance

Junction to Ambient/Junction to Case

N/P (Plastic) Packages . . . . . . . . . . . . . . . . . .140/55°C/W

*Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

PIN CONFIGURATIONS

DIP PLCC