LT6402-12 Linear Technology Corporation, LT6402-12 Datasheet
LT6402-12
Related parts for LT6402-12
LT6402-12 Summary of contents
Page 1
... The LT6402-12 can be used in data acquisition systems required to function at frequencies down to DC. The LT6402-12 operates supply and consumes 30mA. It comes in a compact 16-lead 3mm × 3mm QFN package and operates over a –40°C to 85°C temperature range. Distortion vs Frequency, Differential Input – ...
Page 2
... LT6402-12 ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage ( CCA CCB ...................................................5.5V EEA EEB EEC Input Current (+INA, –INA, +INB, –INB, , ENABLE) ................................................±10mA V OCM Output Current (Continuous) +OUT, –OUT ...................................................±100mA +OUTFILTERED, –OUTFILTERED ......................±30mA Output Short-Circuit Duration (Note 2) ............ Indefi nite Operating Temperature Range (Note 3).... –40°C to 85°C Specifi ...
Page 3
... Single-Ended Single-Ended Differential (+OUT, –OUT 1.2V to 3.6V OCM Differential (+OUT, –OUT 1.4V to 3.4V OCM Single-Ended Measured from V to Average of +OUT and –OUT OCM ENABLE = 0.8V ENABLE = 2V ENABLE = 0.8V ENABLE = 5.5V LT6402-12 = 0V, ENABLE = 0.8V, +INA = EEA EEB EEC unless otherwise noted. LOAD MIN TYP MAX l 0.5 l 4.3 l ...
Page 4
... LT6402-12 AC ELECTRICAL CHARACTERISSTICS ⎯ E ⎯ N ⎯ A ⎯ B ⎯ L ⎯ 0.8V, +INA shorted to +INB (+IN), –INA shorted to –INB (–IN), V unless otherwise noted. SYMBOL PARAMETER Input/Output Characteristics –3dBBW –3dB Bandwidth 0.1dBBW Bandwidth for 0.1dB Flatness 0.5dBBW Bandwidth for 0.5dB Flatness SR Slew Rate t 1% Settling s1% ...
Page 5
... The LT6402I is guaranteed to meet specifi ed performance from –40°C to 85°C. Note 5: Since the LT6402- feedback amplifi er with low output impedance, a resistive load is not required when driving an ADC. Therefore, typical output power is very small. In order to compare the ...
Page 6
... LT6402-12 TYPICAL PERFORMANCE CHARACTERISTICS Third Order Intermodulation Distortion vs Frequency, Differential Input LOAD –65 2 TONES 2V COMPOSITE P-P –70 1MHz TONE SPACING –75 UNFILTERED OUTPUTS –80 –85 FILTERED OUTPUTS –90 – FREQUENCY (MHz) 64026 G04 Output Third Order Intercept vs Frequency, Differential Input 400Ω ...
Page 7
... UNFILTERED OUTPUTS 110 100 PSRR 90 80 CMRR 100 1000 FREQUENCY (MHz) 640212 G20 LT6402-12 Reverse Isolation vs Frequency 0 UNFILTERED OUTPUTS –10 –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 1 10 100 1000 FREQUENCY (MHz) 640212 G15 Input Refl ...
Page 8
... OUT P-P –80 HD3 –85 HD2 –90 –95 –100 1 1.2 1.4 1.6 1.8 OUTPUT COMMON MODE VOLTAGE (V) 640212 G23 10MHz 8192 Point FFT, LT6402-12 Driving an LTC2249 14-Bit ADC 0 8192 POINT FFT – 10MHz, –1dBFS IN –20 FILTERED OUTPUTS –30 –40 –50 –60 –70 –80 –90 –100 – ...
Page 9
... Block Diagram). This fi lter has a –3dB bandwidth of 75MHz. ENABLE (Pin 11): This pin is a TTL logic input referenced to the V pin. If low, the LT6402-12 is enabled and draws CC EEC typically 30mA of supply current. If high, the LT6402-12 is disabled and draws typically 250μA. ...
Page 10
... V CCB CCC EEA Referring to the block diagram, the LT6402-12 uses a closed-loop topology which incorporates 3 internal am- plifi ers. Two of the amplifi ers (A and B) are identical and drive the differential outputs. The third amplifi used to set the output common mode voltage. Gain and input impedance are set by the 200Ω ...
Page 11
... Driving ADCs The LT6402-12 has been specifi cally designed to interface directly with high speed Analog to Digital Converters (ADCs). In general, these ADCs have differential inputs, with an input impedance of 1kΩ or higher. In addition, there is generally some form of lowpass or bandpass fi ...
Page 12
... ADC to limit input noise at the ADC, thereby improving system signal to noise ratio. Both the unfi ltered and fi ltered outputs of the LT6402-12 can easily drive the high impedance inputs of these differential ADCs. If the fi ltered outputs are used, then cutoff frequency and the type of fi ...
Page 13
... F08 Figure 8. LT6402-12 Output Filter Modifi ed for Bandpass Filtering (1 External Inductor, 1 External Capacitor) Output Common Mode Adjustment The LT6402-12’s output common mode voltage is set by the V pin high-impedance input, capable of setting OCM the output common mode voltage anywhere in a range from 1 ...
Page 14
... P low-noise ADCs. This additional output swing improves system SNR 4dB. Input Bias Voltage and Bias Current The input pins of the LT6402-12 are internally biased to the voltage applied to the V pin. No external biasing OCM resistors are needed, even for AC-coupled operation. The ...
Page 15
... Plastic QFN (3mm × 3mm) (Reference LTC DWG # 05-08-1691) 0.70 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 0.75 ± 0.05 (4 SIDES) 1.45 ± 0.10 (4-SIDES) 0.200 REF 0.00 – 0.05 LT6402-12 BOTTOM VIEW—EXPOSED PAD PIN 1 NOTCH R = 0.20 TYP R = 0.115 OR 0.25 × 45° CHAMFER TYP 15 16 0.40 ± 0. (UD16) QFN 0904 0.25 ± 0.05 ...
Page 16
... R10 ENABLE EEC CCB EEB 24.9Ω –INB –OUT R8 [ –INA –OUTFILTERED L1 R7 LT6402-12 [1] [ +INB +OUTFILTERED R9 24.9Ω +INA +OUT CCC OCM CCA EEA ...