AD7324 Analog Devices, AD7324 Datasheet
AD7324
Specifications of AD7324
Available stocks
Related parts for AD7324
AD7324 Summary of contents
Page 1
... The ADC contains a 2.5 V internal reference. The AD7324 also allows for external reference operation reference is applied to the REFIN/OUT pin, the AD7324 can accept a true bipolar ±12 V analog input. Minimum ± supplies are required for the ±12 V input range. The ADC has a high speed serial interface that can operate at throughput rates MSPS ...
Page 2
... Sequencer Operation ..................................................................... 25 Reference ..................................................................................... 27 V ............................................................................................ 27 DRIVE Modes of Operation ....................................................................... 28 Normal Mode .............................................................................. 28 Full Shutdown Mode .................................................................. 28 Autoshutdown Mode ................................................................. 29 Autostandby Mode ..................................................................... 29 Power vs. Throughput Rate ....................................................... 30 Serial Interface ................................................................................ 31 Microprocessor Interfacing ........................................................... 32 AD7324 to ADSP-218x .............................................................. 32 AD7324 to ADSP-BF53x ........................................................... 32 Application Hints ........................................................................... 33 Layout and Grounding .............................................................. 33 Power Supply Configuration .................................................... 33 Outline Dimensions ....................................................................... 34 Ordering Guide .......................................................................... 34 Rev Page ...
Page 3
... All dc accuracy specifications are typical for mode. Single-ended/pseudo differential mode 1 LSB = FSR/4096, unless otherwise noted. Differential mode 1 LSB = FSR/8192, unless otherwise noted. Differential mode Single-ended/pseudo differential mode Differential mode Single-ended/pseudo differential mode Single-ended/pseudo differential mode (LSB = FSR/8192) AD7324 = 2 REF ...
Page 4
... AD7324 1 Parameter Min 2 Differential Nonlinearity 2, 5 Offset Error 2, 5 Offset Error Match Gain Error 2, 5 Gain Error Match Positive Full-Scale Error 2, 6 Positive Full-Scale Error Match 2, 6 Bipolar Zero Error 2, 6 Bipolar Zero Error Match 2, 6 Negative Full-Scale Error ...
Page 5
... MSPS SAMPLE −16 5. DRIVE f = 250 kSPS SAMPLE −16 5. DRIVE SCLK on or off −16 5. DRIVE SCLK on or off −16 5. DRIVE AD7324 < 4.75 V ...
Page 6
... AD7324 1 Parameter Min POWER DISSIPATION Normal Mode (Operational) Full Shutdown Mode 1 Temperature range is −40°C to +85°C. 2 See the Terminology section. 3 Sample tested during initial release to ensure compliance. 4 For dc accuracy specifications, the LSB size for differential mode is FSR/8192. For single-ended mode/pseudo differential mode, the LSB size is FSR/4096, unless otherwise noted ...
Page 7
... SEL2 Figure 2. Serial Interface Timing Diagram Rev Page 2 3.0 V internal/external, REF 1 ) and timed from a voltage level of 1.6 V. DRIVE at 20 ns, the mark space ratio needs to be limited QUIET DB1 DB0 THREE-STATE DON’T LSB CARE AD7324 ...
Page 8
... JC Pb-Free Temperature, Soldering Reflow ESD 1 If the analog inputs are being driven from alternative V circuitry, Schottky diodes should be placed in series with the AD7324 V and V supplies. See Power Supply Configuration section Transient currents 100 mA do not cause SCR latch-up. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only ...
Page 9
... V Positive Power Supply Voltage. This is the positive supply voltage for the analog input section Analog Supply Voltage, 2 5.25 V. This is the supply voltage for the ADC core on the AD7324. CC This supply should be decoupled to AGND. Specifications apply from Logic Power Supply Input. The voltage supplied at this pin determines at what voltage the interface DRIVE operates ...
Page 10
... AD7324 TYPICAL PERFORMANCE CHARACTERISTICS 0 4096 POINT FFT V CC – 25°C A INT/EXT 2.5V REFERENCE –40 ±10V RANGE F = 50kHz IN SNR = 77.30dB –60 SINAD = 76.85dB THD = –86.96dB SFDR = –88.22dB –80 –100 –120 –140 0 50 100 150 200 250 300 FREQUENCY (kHz) Figure 4 ...
Page 11
... RANGE = ±10V 8k 10k SAMPLES T = 25° 228 303 0 0 –2 – CODE Figure 15. Histogram of Codes, True Differential Mode AD7324 ±2.5V DIFF ±2. ±12V SS = 25°C 1000 500 600 = ±12V ...
Page 12
... AD7324 8k 7600 1201 –3 –2 –1 0 CODE Figure 16. Histogram of Codes, Single-Ended Mode –50 –55 –60 –65 – –75 – –85 DIFFERENTIAL MODE F IN – –95 A –100 0 200 400 600 RIPPLE FREQUENCY (kHz) Figure 17 ...
Page 13
... RANGE –85 R ±2.5V RANGE –90 R ±2.5V RANGE –95 10 100 INPUT FREQUENCY (kHz) Figure 22. THD vs. Analog Input Frequency for Various Source Impedances, Single-Ended Mode = 100Ω 50Ω 2000Ω 1000Ω 100Ω 50Ω, IN 1000 Rev Page AD7324 ...
Page 14
... N-bit converter with a sine wave input is given by Signal to (Noise + Distortion) = (6. 1.76) dB For a 13-bit converter, this is 80.02 dB. Total Harmonic Distortion Total harmonic distortion (THD) is the ratio of the rms sum of harmonics to the fundamental. For the AD7324 defined as where sixth harmonics. ...
Page 15
... Figure 14 shows the worst- case across all eight channels for the AD7324. The analog input range is programmed to be the same on all channels. Intermodulation Distortion ...
Page 16
... AD7324 THEORY OF OPERATION CIRCUIT INFORMATION The AD7324 is a fast, 4-channel, 12-bit plus sign, bipolar input, serial ADC. The AD7324 can accept bipolar input ranges that include ±10 V, ±5 V, and ±2 can also accept +10 V unipolar input range. A different analog input range can be programmed on each analog input channel via the on-chip registers ...
Page 17
... The analog inputs of the AD7324 can be configured as single- ended, true differential, or pseudo differential via the control register mode bits (see Table 10). The AD7324 can accept true bipolar input signals. On power-up, the analog inputs operate as four single-ended analog input channels. If true differential or pseudo differential is required, a write to the control register is necessary after power-up to change this configuration ...
Page 18
... AD7324, the value of R includes the on resistance of the input multiplexer and is typically 300 Ω. R any extra source impedance on the analog input. The AD7324 enters track mode on the 14 When running the AD7324 at a throughput rate of 1 MSPS with MHz SCLK signal, the ADC has approximately 1 ...
Page 19
... RANGE SELECTED. Figure 32. Typical Connection Diagram ANALOG INPUT Single-Ended Inputs The AD7324 has a total of four analog inputs when operating in single-ended mode. Each analog input can be independently programmed to one of the four analog input ranges. In applications where the signal source is high impedance recommended to buffer the signal before applying it to the ADC analog inputs ...
Page 20
... V − pin for the different analog input ranges when configured IN in the pseudo differential mode. For example, when the AD7324 is configured to operate in pseudo differential mode and the ±5 V range is selected with ±16 pin can vary from −6 +6.5 V. Rev Page ± ...
Page 21
... THD starts to degrade. Due to the programmable nature of the analog inputs on the AD7324, the choice of op amp used to drive the inputs is a function of the particular application and depends on the input configuration and the analog input voltage ranges selected. ...
Page 22
... ADDRESSING REGISTERS A serial transfer on the AD7324 consists of 16 SCLK cycles. The three MSBs on the DIN line during the 16 SCLK transfer are decoded to determine which register is addressed. The three MSBs consist of the write bit, Register Select 1 bit, and Register Select 2 bit. The register select bits are used to determine which of the three on-board registers is selected ...
Page 23
... SEQUENCE REGISTER The sequence register on the AD7324 is a 4-bit, write-only register. Each of the four analog input channels has one corresponding bit in the sequence register. To select a channel for inclusion in the sequence, set the corresponding channel bit the sequence register. ...
Page 24
... write to the range register is selected by setting the write bit to 1 and the register select bits to 0 and 1. After the initial write to the range register occurs, each time an analog input is selected, the AD7324 automatically configures the analog input to the appropriate range, as indicated by the range register. The ± ...
Page 25
... Seq1 to 0 and Seq2 to 1. The AD7324 continues to convert the selected sequence without interruption provided that the sequence register remains unchanged, and Seq1 = 0 and Seq2 = 1 in the control register ...
Page 26
... Bit ADD1 to Bit ADD0 in the control register. In this configuration, there is no need for a write to the sequence register. To operate the AD7324 in this mode, set Seq1 to 1 and Seq2 the control register, and then select the final channel in the sequence by programming Bit ADD1 to Bit ADD0 in the control register ...
Page 27
... The AD7324 is specified for a 2 reference range. When reference is selected, the ranges are ±12 V, ±6 V, ±3 V, and +12 V. For these ranges, the V must be equal to or greater than the maximum analog input range selected, see Table 6 ...
Page 28
... NORMAL MODE (PM1 = PM0 = 0) This mode is intended for the fastest throughput rate performance, with the AD7324 being fully powered up at all times. Figure 46 shows the general operation of the AD7324 in normal mode. The conversion is initiated on the falling edge and the track-and-hold enters hold mode as described in the Interface section ...
Page 29
... DATA INTO CONTROL REGISTER DIN CONTROL REGISTER IS LOADED ON THE FIRST 15 CLOCKS, PM1 = 1, PM0 = the case with the autoshutdown mode, the AD7324 enters standby on the 15 updated (see Figure 48). The part retains information in the registers during standby. Once in autostandby mode, the CS signal must remain low to keep the part in autostandby mode. ...
Page 30
... AD7324 POWER VS. THROUGHPUT RATE The power consumption of the AD7324 varies with throughput rate. The static power consumed by the AD7324 is very low, and a significant power savings can be achieved as the throughput rate is reduced. Figure 49 and Figure 50 shows the power vs. throughput rate for the AD7324 respectively ...
Page 31
... REG WRITE DIN SEL1 Data is clocked into the AD7324 on the SCLK falling edge. The 3 MSBs on the DIN line are decoded to select which register is being addressed. The control register is a 12-bit register. If the control register is addressed by the 3 MSBs, the data on the DIN ...
Page 32
... AD7324 MICROPROCESSOR INTERFACING The serial interface on the AD7324 allows the part to be directly connected to a range of different microprocessors. This section explains how to interface the AD7324 with some common microcontroller and DSP serial interface protocols. AD7324 TO ADSP-218x The ADSP-21xx family of DSPs interface directly to the AD7324 without requiring glue logic ...
Page 33
... All AGND pins on the AD7324 should be connected to the AGND plane. Digital and analog ground pins should be joined in only one place. If the AD7324 system where multiple devices require an AGND and DGND connection, the connection should still be made at only one point ...
Page 34
... This board is a complete unit allowing control and communicate with all Analog Devices evaluation boards ending in the CB designators. To order a complete evaluation kit, the particular ADC evaluation board (for example, EVAL-AD7324CB), the EVAL-CONTROL BRD2, and transformer must be ordered. See the relevant evaluation board technical note for more information ...
Page 35
... NOTES Rev Page AD7324 ...
Page 36
... AD7324 NOTES ©2005–2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04864-0-1/10(A) Rev Page ...