Electronic Components Datasheet Search |
|
MAX1172CDJ Datasheet(PDF) 9 Page - Maxim Integrated Products |
|
MAX1172CDJ Datasheet(HTML) 9 Page - Maxim Integrated Products |
9 / 12 page 12-Bit, 30Msps, TTL-Output ADC _______________________________________________________________________________________ 9 AGND and DGND are the two grounds available on the MAX1172. These two internal grounds are isolated on the device. The use of ground planes is recommended to achieve optimum device performance. DGND is needed for the DVCC return path (40mA typical) and for the return path for all digital output logic interfaces. AGND and DGND should be separated from each other and connected together only at the device through a ferrite bead. A Schottky or hot carrier diode connected between AGND and VEE is required. The use of separate power supplies between VCC and DVCC is not recommended due to potential power-supply sequencing latchup con- ditions. Use of the recommended interface circuit shown in Figure 2 will provide optimum device performance for the MAX1172. Voltage Reference The MAX1172 requires the use of two voltage refer- ences: VFT and VFB. VFT is the force for the top of the voltage reference ladder (+2.5V typical), VFB (-2.5V typical) is the force for the bottom of the voltage refer- ence ladder. Both voltages are applied across an inter- nal reference ladder resistance of 800 Ω. The +2.5V voltage source for reference VFT must be current limit- ed to 20mA maximum if a different driving circuit is used in place of the recommended reference circuit shown in Figures 2 and 3. In addition, there are five reference ladder taps (VST, VRT1, VRT2, VRT3, and VSB). VST is the sense for the top of the reference ladder (+2.0V), VRT2 is the mid- point of the ladder (0.0V typical), and VSB is the sense for the bottom of the reference ladder (-2.0V). VRT1 and VRT3 are quarter-point ladder taps (+1.0V and -1.0V typical, respectively). The voltages seen at VST and VSB are the true full-scale input voltages of the device when VFT and VFB are driven to the recommended volt- ages (+2.5V and -2.5V typical, respectively). VST and VSB can be used to monitor the actual full-scale input voltage of the device. VRT1, VRT2, and VRT3 should not be driven to the expected ideal values, as is commonly done with standard flash converters. A decoupling capacitor of 0.01µF connected to AGND from each tap is recommended to minimize high-frequency noise injection. The analog input range will scale proportionally with respect to the reference voltage if a different input range is required. The maximum scaling factor for device operation is ±20% of the recommended refer- ence voltages of VFT and VFB. However, because the MAX1172 is laser trimmed to optimize performance with ±2.5V references, its accuracy will degrade if operated beyond a ±2% range. An example of a recommended reference driver circuit is shown in Figure 2. IC1 is REF-03, the +2.5V refer- ence with a tolerance of 0.6% or ±0.015V. The 10k Ω potentiometer supports an adjustable range of 150mV. IC2 is recommended to be an OP-07 or equivalent device. R2 and R3 must be matched to within 0.1% with good TC tracking to maintain a 0.3LSB matching between VFT and VFB. If 0.1% matching is not met, then potentiometer R4 can be used to adjust the VFB voltage to the desired level. Adjust R1 and R4 such that VST and VSB are exactly +2.0V and -2.0V, respectively. The following errors are defined: +FS error = top of ladder offset voltage = ∆(+FS - VST) -FS error = bottom of ladder offset voltage = ∆(-FS - VSB) Where the +FS (full scale) input voltage is defined as the output 1LSB above the transition of 1–10 and 1–11, and the -FS input voltage is defined as the output 1LSB below the transition of 0–00 and 0–01. VFT VIN VCC VEE Figure 3. Analog Equivalent Input Circuit |
Similar Part No. - MAX1172CDJ |
|
Similar Description - MAX1172CDJ |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |