LTC2757 Linear Technology, LTC2757 Datasheet
LTC2757
Available stocks
Related parts for LTC2757
LTC2757 Summary of contents
Page 1
... In addition to its precision DC specifi cations, the LTC2757 also offers excellent AC specifi cations, including 2.1μs full-scale settling to 1LSB and 1.4nV The LTC2757 uses a bidirectional input/output parallel interface that allows readback of any on-chip register, including DAC output-range settings ...
Page 2
... D17-D0 to GND ............... –0. WR, UPD, D/S, READ, M-SPAN, CLR to GND .................................. –0. Operating Temperature Range LTC2757C .................................................... 0°C to 70°C LTC2757I..................................................–40°C to 85°C Maximum Junction Temperature .......................... 150°C Storage Temperature Range .................. –65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C ...
Page 3
... Range, Code = Full-Scale, –3dB Bandwidth Range ±10V, 10kHz Sine Wave REF (Note 10) Multiplying (Note 11 OUT1 www.DataSheet4U.com LTC2757 l denotes the = 25°C. A LTC2757B LTC2757A TYP MAX MIN TYP MAX 18 18 ±1 ±0.4 ±1 ±2 ±0.4 ±1 ±48 ±5 ± ...
Page 4
... LTC2757 ELECTRICAL CHARACTERISTICS specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T SYMBOL PARAMETER Power Supply V Supply Voltage DD I Supply Current Digital Inputs V Digital Input High Voltage IH V Digital Input Low Voltage ...
Page 5
... DAC code = FS. Output RMS amplifi LT1468. and from Note 11: Calculation from V OUT1 (Boltzmann constant resistance (Ω), T = temperature (°K), and B = bandwidth (Hz). Note 12: Guaranteed by design. Not production tested. www.DataSheet4U.com LTC2757 l denotes specifi cations that MIN TYP MAX UNITS ...
Page 6
... LTC2757 TYPICAL PERFORMANCE CHARACTERISTICS V = 5V 25°C, unless otherwise noted Integral Nonlinearity (INL) 1.0 ±10V RANGE 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 65536 131072 196608 262143 CODE 2757 G01 INL vs Temperature 1 10V RANGE 0.8 0.6 +INL 0.4 0.2 0 –INL –0.2 –0.4 –0.6 –0.8 –1.0 –40 – ...
Page 7
... RISING MAJOR CARRY TRANSITION. FALLING TRANSITION IS SIMILAR OR BETTER. Logic Threshold vs Supply Voltage 2 1.75 1.5 RISING 1.25 FALLING 1 0.75 0.5 2.5 3 3 (V) DD 2757 G16 www.DataSheet4U.com LTC2757 Multiplying Frequency Response vs Digital Code ALL BITS ON 0 D17 D16 D15 –20 D14 D13 D12 –40 D11 D10 D9 D8 – – – ...
Page 8
... M-SPAN (Pin 21): Manual Span Control Input. M-SPAN can be pin-strapped to confi gure the LTC2757 for opera- tion in a single, fi xed output range. To confi gure the part for single-span use, tie M-SPAN directly to V ...
Page 9
... DAC WITH SPAN SELECT 3 18 DAC CONTROL REGISTER REGISTER LOGIC 3 18 INPUT INPUT REGISTER REGISTER I/O PORT PORT 37, 38 8-16, 23-31 SPAN I/O DATA I/O S2-S0 D17-D0 www.DataSheet4U.com LTC2757 and REF . Normally 41 OSADJ 39 I OUT1 40 I OUT2F 6 I OUT2S 5 DAC I/O 2757 BD 2757f 9 ...
Page 10
... LTC2757 TIMING DIAGRAMS WR I/O INPUT UPD D/S CLR READ WR I/O INPUT I/O OUTPUT UPD D/S 10 Write, Update and Clear Timing VALID VALID Readback Timing VALID VALID www.DataSheet4U.com t 25 2757 TD01 ...
Page 11
... Manual Span Confi guration ), the DACs power-up in the manually-chosen range at the appropriate code. Manual Span Confi guration Multiple output ranges are not needed in some applica- tions. To confi gure the LTC2757 for single-span opera- and the D/S pin to GND. tion, tie the M-SPAN pin ...
Page 12
... Many systems require compensation for overall system Update DAC Register offset. This may be an order of magnitude or more greater Read Input Register than the offset of the LTC2757, which is so low Read DAC Register dominated by external output amplifi er errors even when - using the most precise op amps ...
Page 13
... This OSADJ pin should be driven with a Thevenin-equivalent impedance of 10k or less to preserve the settling performance of the LTC2757. It should be shorted to GND if not used. The GE pin has an input impedance of 2.56MΩ, and ADJ is intended for use with fi xed reference voltages only. It should be shorted to GND if not used ...
Page 14
... LTC2757 OPERATION—EXAMPLES 2. Load ±10V range with the output at 5V, changing to –5V. WR SPAN I/O INPUT DATA I/O 30000 INPUT UPD D/S READ = LOW 0V V OUT 3. Write and update mid-scale code range (V and DAC registers before updating. WR DATA I/O 20000 H INPUT HI-Z DATA I/O OUTPUT UPD ...
Page 15
... APPLICATIONS INFORMATION Op Amp Selection Because of the extremely high accuracy of the 18-bit LTC2757, careful thought should be given to op amp selection in order to achieve the exceptional performance of which the part is capable. Fortunately, the sensitivity of INL and DNL to op amp offset has been greatly reduced compared to previous generations of multiplying DACs ...
Page 16
... LTC2757 APPLICATIONS INFORMATION Table 5. Partial List of LTC Precision Amplifi ers Recommended for Use with the LTC2757 with Relevant Specifi cations AMPLIFIER μV nA LTC1150 10 0.05 LT1001 25 2 LT1012 25 0.1 LT1097 50 0.35 LT1468 75 10 Table 5 contains a partial list of LTC precision op amps recommended for use with the LTC2757. The easy-to-use design equations simplify the selection of op amps to meet the system’ ...
Page 17
... DC offset. Precision Voltage Reference Considerations Much in the same way selecting an operational amplifi er for use with the LTC2757 is critical to the performance of the system, selecting a precision voltage reference also requires due diligence. The output voltage of the LTC2757 is directly affected by the voltage reference ...
Page 18
... BARRIER DIODE 150pF ADJ 48 47 45, 46 43 REF R COM OFS LTC2757 18-BIT DAC WITH SPAN SELECT OSADJ 3, 37, 38 8-16, 23-31 39 SPAN I/O DATA I/O V OSADJ S2-S0 D17-D0 DAC with Two Optional Circuits OUT from GND with a Force/Sense Amplifi er OUT2 www ...
Page 19
... REF 7.15 – 7.25 C0.30 – 0.50 R0.08 – 0.20 GAUGE PLANE 0.25 0° – 7° 0.50 0.09 – 0.20 BSC SECTION A – PIN-1 INDENTIFIER IS A MOLDED INDENTATION, 0.50mm DIAMETER 5. DRAWING IS NOT TO SCALE www.DataSheet4U.com LTC2757 9.00 BSC 7.00 BSC 48 SEE NOTE: 4 7.00 BSC A A 1.35 – 1.45 0.17 – 0.27 0.05 – 0.15 9.00 BSC 1.60 MAX LX48 LQFP 0907 REVØ ...
Page 20
... REF REF OFS OFS OUT1 I OUT2F LTC2757 I OUT2S GND V OSADJ M-SPAN GND GND GND 2757 F03 COMMENTS Integrated 4-Quadrant Resistors Software-Selectable (SoftSpan) Ranges, ±1LSB INL, DNL, 16-Lead SSOP Package ±1LSB INL, DNL 10V –10V, ±10V Output Ranges Single DACs ± ...