FUNCTIONAL BLOCK DIAGRAM

REV. A

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a

12-Bit Ultrahigh Speed

Monolithic D/A Converter

AD568

FEATURES

Ultrahigh Speed: Current Settling to 1 LSB in 35 ns

High Stability Buried Zener Reference on Chip

Monotonicity Guaranteed Over Temperature

10.24 mA Full-Scale Output Suitable for Video

Applications

Integral and Differential Linearity Guaranteed Over

Temperature

0.3" “Skinny DIP” Packaging

Variable Threshold Allows TTL and CMOS

Interface

MIL-STD-883 Compliant Versions Available

PRODUCT DESCRIPTION

The AD568 is an ultrahigh-speed, 12-bit digital-to-analog con-

verter (DAC) settling to 0.025% in 35 ns. The monolithic de-

vice is fabricated using Analog Devices’ Complementary Bipolar

(CB) Process. This is a proprietary process featuring high-speed

NPN and PNP devices on the same chip without the use of di-

electric isolation or multichip hybrid techniques. The high speed

of the AD568 is maintained by keeping impedance levels low

enough to minimize the effects of parasitic circuit capacitances.

The DAC consists of 16 current sources configured to deliver a

10.24 mA full-scale current. Multiple matched current sources

and thin-film ladder techniques are combined to produce bit

weighting. The DAC’s output is a 10.24 mA full scale (FS) for

current output applications or a 1.024 V FS unbuffered voltage

output. Additionally, a 10.24 V FS buffered output may be gen-

erated using an onboard 1 k

Ω span resistor with an external op

amp. Bipolar ranges are accomplished by pin strapping.

Laser wafer trimming insures full 12-bit linearity. All grades of

the AD568 are guaranteed monotonic over their full operating

temperature range. Furthermore, the output resistance of the

DAC is trimmed to 100

Ω ± 1.0%. The gain temperature coeffi-

cient of the voltage output is 30 ppm/

°C max (K).

The AD568 is available in three performance grades. The

AD568JQ and KQ are available in 24-pin cerdip (0.3") packages

and are specified for operation from 0

°C to +70°C. The

AD568SQ features operation from –55

°C to +125°C and is also

packaged in the hermetic 0.3" cerdip.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

PRODUCT HIGHLIGHTS

1. The ultrafast settling time of the AD568 allows leading edge

performance in waveform generation, graphics display and

high speed A/D conversion applications.

2. Pin strapping provides a variety of voltage and current output

ranges for application versatility. Tight control of the abso-

lute output current reduces trim requirements in externally-

scaled applications.

3. Matched on-chip resistors can be used for precision scaling in

high speed A/D conversion circuits.

4. The digital inputs are compatible with TTL and +5 V

CMOS logic families.

5. Skinny DIP (0.3") packaging minimizes board space require-

ments and eases layout considerations.

6. The AD568 is available in versions compliant with MIL-

STD-883. Refer to the Analog Devices Military Products

Databook or current AD568/883B data sheet for detailed

specifications.