±1LSB 18-Bit Serial DACs VREFA ±1LSB INL Max 1.0 VDD 2.7V to 5.5V ±10V Range 0.8 0.6 VOUTA 0.4 INL (LSB) LT1468 3-Wire SPI with Data Readback 0.2 0 –0.2 –0.4 VOUTB –0.6 90°C 25°C –45°C –0.8 LT1468 –1.0 0 65536 131072 196608 262143 CODE VREFB Single and Dual 18-Bit Precision DACs The LTC®2756 single and LTC2758 dual current output digital-to-analog converters (DACs) offer true 18-bit precision DC specifications with maximum ±1LSB INL and DNL over temperature. The fast settling time and low glitch impulse allows generation of high frequency and low noise output waveforms. Integrated precision resistors allow reference inversion, gain and offset adjustment and bipolar level-shift, eliminating expensive external precision resistors and gain stages. The 3-wire bidirectional serial SPI interface provides a software interface to set the DAC output span and enables readback of internal registers. Features Maximum 18-Bit INL Error: ±1LSB over Temperature Guaranteed Monotonic over Temperature Program or Pin-Strap Six Output Ranges: 0V to 5V, 0V to 10V, –2.5V to 7.5V, ±2.5V, ±5V, ±10V 18-Bit Settling Time: 2.1μs Glitch Impulse: 0.4nV•s (3V), 2nV•s (5V) Temperature Drift: ±0.2LSB INL Drift from –40°C to 85°C ±0.25ppm/°C Gain Drift ±0.15ppm/°C Bipolar Zero Drift Power Supply Rejection: ±0.8LSB/V Voltage-Controlled Offset and Gain Trims Serial Interface with Readback of All Registers Clear and Power-On Reset to 0V Regardless of Output Range 2.7V to 5.5V Single Supply Operation 48-Pin 7mm × 7mm LQFP Package (LTC2758) 28-Lead SSOP Package (LTC2756) SoftSpan™ Selectable Output Spans n n 10V n 5V n n 0 n n n n –5V n n n –10V n n n n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and SoftSpan is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Single/Dual/Quad IOUT R-2R Multiplying DACs Single Serial I/O Single Parallel I/O Dual Serial I/O 18-Bit 2756 2757 2758 16-Bit 1592 2751-16 2752 14-Bit 1589 2751-14 12-Bit 1588 2751-12 Dual Parallel I/O Quad Serial I/O Quad Parallel I/O 2753-16 2754-16 2755-16 2753-14 1590 2755-14 2753-12 2754-12 2755-12 DAC Architecture The LTC2756 and LTC2758 use a current output R-2R or 4-quadrant multiplying DAC architecture. This architecture offers many advantages for high precision applications. The reference load impedance is constant and can be driven with an unbuffered reference or a slow low precision op amp with no impact on static or dynamic performance. Internal feedback and level-shift resistors simplify the output loop design and eliminate the need for external precision resistors. The unbuffered output and selectable voltage range give designers maximum flexibility to choose the best amplifier for their applications. REF 5V + LT1012 – RIN 150pF RCOM REF ROFS RFB 27pF SPI WITH READBACK IOUT1 18-BIT DAC WITH SPAN SELECT 5V IOUT2 VDD GND – LT1468 VOUT + 0.1µF LTC2756 VOSADJ GEADJ GAIN ADJUST SPAN I/O S2-S0 OFFSET ADJUST www.linear.com/2758 n 1-800-4-LINEAR 0811