mx7705 Maxim Integrated Products, Inc., mx7705 Datasheet
mx7705
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mx7705 Summary of contents
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... The device offers an SPI™-/QSPI™-/ MICROWIRE™-compatible serial interface. The MX7705 operates from a single 2.7V to 5.25V supply. The operating supply current is 320µA (typ) with a 3V supply. Power-down mode reduces the supply current to 2µ ...
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Low-Power, 2-Channel, Sigma-Delta ADC ABSOLUTE MAXIMUM RATINGS V to GND ..............................................................-0.3V to +6V DD All Other Pins to GND.................................-0. Maximum Current Input into Any Pin ..................................50mA Continuous Power Dissipation (T = +70°C) A PDIP (derate 10.5mW/°C above ...
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ELECTRICAL CHARACTERISTICS (continued 5V, GND = 1.225V for V DD REF+ 2.4576MHz, CLKDIV bit = GND = 0.1µF, C REF+ PARAMETER SYMBOL AIN Input Capacitance AIN Input Sampling Rate Input ...
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Low-Power, 2-Channel, Sigma-Delta ADC ELECTRICAL CHARACTERISTICS (continued 5V, GND = 1.225V for V DD REF+ 2.4576MHz, CLKDIV bit = GND = 0.1µF, C REF+ PARAMETER SYMBOL CLKIN INPUT CLKIN ...
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ELECTRICAL CHARACTERISTICS (continued 5V, GND = 1.225V for V DD REF+ 2.4576MHz, CLKDIV bit = GND = 0.1µF, C REF+ PARAMETER SYMBOL POWER REQUIREMENTS Power-Supply Voltage Power-Supply Current (Note 12) ...
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Low-Power, 2-Channel, Sigma-Delta ADC TIMING CHARACTERISTICS ( 5V, GND = 1.225V for V DD REF+ 2.4576MHz, CLKDIV bit = GND = 0.1µF, C REF+ (Figures 8, 9) PARAMETER SYMBOL DRDY ...
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... Note 6: Gain-error drift does not include unipolar offset drift or bipolar zero drift. Effectively the drift of the part if only zero- scale calibrations are performed. Note 7: The analog input voltage range on AIN+ is given with respect to the voltage on AIN- on the MX7705. Note 8: This common-mode voltage range is allowed, provided that the input voltage on analog inputs does not go more positive than (V + 30mV) or more negative than (GND - 30mV) ...
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Low-Power, 2-Channel, Sigma-Delta ADC Table 1. Output RMS Noise vs. Gain and Output Data Rate (V FILTER FIRST -3dB FREQUENCY NOTCH AND OUTPUT DATA RATE BUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz 25Hz 6.55Hz 100Hz 26.2Hz 200Hz 52.4Hz UNBUFFERED ...
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Table 2. Peak-to-Peak Resolution vs. Gain and Output Data Rate (V FILTER FIRST NOTCH AND -3dB FREQUENCY OUTPUT DATA RATE BUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz 25Hz 6.55Hz 100Hz 26.2Hz 200Hz 52.4Hz UNBUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz ...
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Low-Power, 2-Channel, Sigma-Delta ADC Table 3. Output RMS Noise vs. Gain and Output Data Rate (V FILTER FIRST NOTCH AND -3dB FREQUENCY OUTPUT DATA RATE BUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz 25Hz 6.55Hz 100Hz 26.2Hz 200Hz 52.4Hz UNBUFFERED ...
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Table 4. Peak-to-Peak Resolution vs. Gain and Output Data Rate (V FILTER FIRST NOTCH AND -3dB FREQUENCY OUTPUT DATA RATE BUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz 25Hz 6.55Hz 100Hz 26.2Hz 200Hz 52.4Hz UNBUFFERED (f = 1MHz) CLKIN 20Hz 5.24Hz ...
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Low-Power, 2-Channel, Sigma-Delta ADC ( 5V 1.225V for V DD REF+ DD OFFSET ERROR vs. SUPPLY VOLTAGE (5V) 0.003 0.002 0.001 0 -0.001 -0.002 -0.003 4.75 4.85 4.95 5.05 5.15 ...
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V = 1.225V for V DD REF+ DD SUPPLY CURRENT vs. SUPPLY VOLTAGE (3V) 0.6 A 0 0.3 E 0.2 2.70 2.85 3.00 3.15 SUPPLY VOLTAGE (V) A: BUFFERED MODE B: ...
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Low-Power, 2-Channel, Sigma-Delta ADC ( 5V 1.225V for V DD REF+ DD SUPPLY CURRENT vs 0.5 0 0.3 E 0.2 0.4 0.6 0.8 1.0 1.2 ...
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... POWER-DOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE (5V) 200 180 160 140 120 100 4.75 4.85 4.95 5.05 5.15 SUPPLY VOLTAGE (V) EXTERNAL OSCILLATOR STARTUP TIME MX7705 toc20 4.9152MHz CRYSTAL 2.4576MHz CRYSTAL 2ms/div Sigma-Delta ADC = +25°C, unless otherwise noted.) A POWER-DOWN SUPPLY CURRENT vs. TEMPERATURE 300 250 200 150 100 V ...
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... Drive CS low to clock data in on DIN and to clock data out on DOUT. When CS is high DOUT is high impedance. Connect CS to GND for 3-wire operation. RESET Active-Low Reset Input. Drive RESET low to reset the MX7705 to power-on reset status AIN2+ Channel 2 Positive Differential Analog Input ...
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... MODULATOR BUFFER SERIAL INTERFACE, REGISTERS, The MX7705 accepts four analog inputs (AIN1+, AIN1-, AIN2+, and AIN2-) in buffered or unbuffered mode. Use Table 8 to select the positive and negative input pair for a fully differential channel. The input buffer iso- lates the inputs from the capacitive load presented by the PGA/modulator, allowing for high source-imped- ance analog transducers ...
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... V REF REF+ REF- 5.25V and 2.5V for V = 2.7V to 3.6V. DD The MX7705 samples REF+ and REF (CLKDIV = 128 (CLKDIV = 1) with an CLKIN internal 10pF (typ for gain = 1) sampling capacitor in series with a 7kΩ (typ) switch on-resistance. Programmable-Gain Amplifier A PGA provides selectable levels of gain 16, 32, 64, and 128 ...
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... Figure 5. MX7705 Bipolar Transfer Function - V . REF- When the MX7705 is in buffered mode, the absolute and common-mode analog input voltage ranges reduce to between (GND + 50mV) and (V input voltage range is not affected in buffered mode. Sigma-Delta ADC V ...
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... This significantly limits the amount of passive anti-aliasing filtering that can be applied in front of the MX7705 in unbuffered mode. In buffered mode, large source impedance causes a small DC-offset error, which can be removed by calibration. ...
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... MX7705. The 8-bit test register is used for factory testing only. The default state of the MX7705 is to wait for a write to the communications register. Any write or read opera- tion on the MX7705 is a two-step process. First, a com- mand byte is written to the communications register ...
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... B select bipolar mode. Set B select unipolar mode. BUF: (Default = 0) Buffer-Enable Bit. For unbuffered mode, disable the internal buffer of the MX7705 to reduce power consumption by writing the BUF bit. Write this bit to enable the buffer. Use the internal buffer when acquiring high source-impedance input signals ...
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... CLKDIV: (Default = 0) Clock-Divider Control Bit. The MX7705 has an internal clock divider. Set this bit divide the input clock by two. When this bit is set to 0, the MX7705 operates at the external oscillator frequency. CLK: (Default = 1) Clock Bit. Set CLK = 1 for f 2.4576MHz with CLKDIV = 0, or 4.9152MHz with CLKDIV = 1 ...
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Low-Power, 2-Channel, Sigma-Delta ADC Table 10. Operating-Mode Selection MD1 MD0 0 0 Normal Mode. Use this mode to perform normal conversions on the selected analog input channel. Self-Calibration Mode. This mode performs self-calibration on the selected channel determined from ...
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... This register is reserved for factory testing of the device. For proper operation of the MX7705, do not change this register from its default power-on reset values. Offset and Gain-Calibration Registers The MX7705 contains one offset register and one gain register for each input channel. Each register is 24 bits wide and can be written and read ...
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... Low-Power, 2-Channel, Sigma-Delta ADC Drive RESET low to reset the MX7705 to power-on reset status. DRDY goes high and all communication to the MX7705 is ignored while RESET is low. Upon releasing RESET, the device must be reconfigured to begin a con- version. The device returns to waiting for a write to the communication register after a reset has been performed ...
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POLL DRDY OUTPUT 1 (DATA NOT READY) 0 (DATA READY) Figure 11. Sample Flow Diagram for Data Conversion ______________________________________________________________________________________ 16-Bit, Low-Power, 2-Channel, POWER-ON RESET INITIALIZE µC/µP SERIAL PORT WRITE TO THE COMMUNICATIONS REGISTER. SELECT CHANNEL 1 AND SET NEXT OPERATION ...
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... PGA gain, and output data rate. The MX7705 offers two calibration modes, self-calibra- tion and system calibration. The channels of the MX7705 are independently calibrated (Table 8). The calibration coefficients resulting from a calibration sequence on a selected channel are stored in the corre- sponding offset and gain-register pair. ...
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... DRDY goes high at the end of this read operation. If the new data remains unread, DRDY stays low until the MX7705 is taken out of power-down mode and resumes data conversion. Resume normal operation by setting The device begins a new ...
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... MX7705, along with the reference voltage in a ratiometric configuration. The on-chip PGA allows the MX7705 to handle an analog input voltage range as low as 20mV to full scale. Temperature Measurement Use the MX7705 for temperature measurements from a thermocouple (Figure 13) ...
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... INL for the MX7705 is measured using the endpoint method. This is the more conservative method. Unipolar Offset Error For an ideal converter, the first transition occurs at 0.5 LSB above zero ...
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Low-Power, 2-Channel, Sigma-Delta ADC (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) 32 ______________________________________________________________________________________ Package Information ...
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For the latest package outline information www.maxim-ic.com/packages TOP VIEW FRONT VIEW ______________________________________________________________________________________ 16-Bit, Low-Power, 2-Channel, Package Information (continued) ...
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... Maxim reserves the right to change the circuitry and specifications without notice at any time. 34 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Package Information (continued) Printed USA is a registered trademark of Maxim Integrated Products, Inc. PACKAGE OUTLINE, TSSOP 4.40mm BODY 1 21-0066 G ...