Datasheet LTC1604 (Analog Devices) - 6

LTC1604
TYPICAL PERFORMANCE CHARACTERISTICS Power Supply Feedthrough vs Input Common Mode Rejection Intermodulaton Distortion Ripple Frequency vs Input Frequency
0 0 80 f f SAMPLE = 333kHz SAMPLE = 333kHz V –20 fIN1 = 29.3kHz RIPPLE = 10mV 70 f –20 IN2 = 32.4kHz 60 –40 –40 50 –60 –60 40 –80 30 AMPLITUDE (dB) –80 A –100 FEEDTHROUGH (dB) VDD 20 –120 AMPLITUDE OF POWER SUPPLY –100 V COMMON MODE REJECTION (dB) SS 10 –140 –120 0 0 20 40 60 80 100 120 140 160 1k 10k 100k 1M 1k 10k 100k 1M FREQUENCY (kHz) INPUT FREQUENCY (Hz) INPUT FREQUENCY (Hz) 1604 G06 1604 G07 1604G09
PIN FUNCTIONS A + IN (Pin 1):
Positive Analog Input. The ADC converts the
OGND (Pin 28):
Digital Ground for Output Drivers. difference voltage between A + – IN and AIN with a differ-
OV
ential range of ±2.5V. A +
DD (Pin 29):
Digital Power Supply for Output Drivers. IN has a ±2.5V input range when Bypass to OGND with 10μF tantalum in parallel with 0.1μF A – IN is grounded. ceramic.
A – IN (Pin 2):
Negative Analog Input. Can be grounded, tied
RD (Pin 30):
Read Input. A logic low enables the output to a DC voltage or driven differentially with A + IN . drivers when CS is low.
VREF (Pin 3):
2.5V Reference Output. Bypass to AGND with
CONVST (Pin 31):
Conversion Start Signal. This active 2.2μF tantalum in parallel with 0.1μF ceramic. low signal starts a conversion on its falling edge when
REFCOMP (Pin 4):
4.375 Reference Compensation Pin. CS is low. Bypass to AGND with 47μF tantalum in parallel with 0.1μF
CS (Pin 32):
The Chip Select Input. Must be low for the ceramic. ADC to recognize CONVST and RD inputs.
AGND (Pins 5 to 8):
Analog Grounds. Tie to analog ground
SHDN (Pin 33):
Power Shutdown. Drive this pin low with plane. CS low for nap mode. Drive this pin low with CS high for
DVDD (Pin 9):
5V Digital Power Supply. Bypass to DGND sleep mode. with 10μF tantalum in parallel with 0.1μF ceramic.
VSS (Pin 34):
–5V Negative Supply. Bypass to AGND with
DGND (Pin 10):
Digital Ground for Internal Logic. Tie to 10μF tantalum in parallel with 0.1μF ceramic. analog ground plane.
AVDD (Pin 35):
5V Analog Power Supply. Bypass to AGND
D15 to D0 (Pins 11 to 26):
Three-State Data Outputs. D15 with 10μF tantalum in parallel with 0.1μF ceramic. is the Most Significant Bit.
AVDD (Pin 36):
5V Analog Power Supply. Bypass to AGND
BUSY (Pin 27):
The BUSY output shows the converter with 10μF tantalum in parallel with 0.1μF ceramic and status. It is low when a conversion is in progress. Data is connect this pin to Pin 35 with a 10Ω resistor. valid on the rising edge of BUSY. 1604fa 6