ISL26134AVZ-T7A Intersil, ISL26134AVZ-T7A Datasheet - Page 20

• Manufacturer Part Number: ISL26134AVZ-T7A
• Description: Analog to Digital Converters - ADC ISL26134AVZ LW-NOISE 24BIT DELTASIGMA ADC
• Manufacturer: Intersil

Specifications of ISL26134AVZ-T7A

• Product Category: Analog to Digital Converters - ADC
• Rohs: yes
• Number Of Channels: 4
• Architecture: Sigma-Delta
• Conversion Rate: 80 sps
• Resolution: 24 bit
• Input Type: Differential
• Snr: No
• Interface Type: Serial (2-Wire)
• Operating Supply Voltage: 5 V
• Maximum Operating Temperature: + 105 C
• Package / Case: TSSOP-28
• Maximum Power Dissipation: 68 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1
• Voltage Reference: External

PCB Board Layout and System
Configuration
The ISL26132,ISL26134 ADC is a very low noise converter. To
achieve the full performance available from the device will
require attention to the printed circuit layout of the circuit board.
Care should be taken to have a full ground plane without
impairments (traces running through it) directly under the chip
on the back side of the circuit board. The analog input signals
should be laid down adjacent (AIN+ and AIN- for each channel) to
achieve good differential signal practice and routed away from
any traces carrying active digital signals. The connections from
the CAP pins to the off-chip filter capacitor should be short, and
without any digital signals nearby. The crystal, if used should be
connected with relatively short leads. No active digital signals
should be routed near or under the crystal case or near the
traces, which connect it to the ADC. The AGND and DGND pins of
the ADC should be connected to a common solid ground plane.
All digital signals to the chip should be powered from the same
supply, as that used for DVDD (do not allow digital signals to be
active high unless the DVDD supply to the chip is alive). Route all
active digital signals in a way to keep distance from any analog
pin on the device (AIN, VREF, CAP, AVDD). Power on the AVDD
supply should be active before the VREF voltage is present.
PCB layout patterns for the chips (ISL26132 and ISL26134) are
found on the respective package outline drawings on pages 22,
and 23.
TYPE K
+5V
5M
5M
10k
10k
20
ISL21009
4.096V
1µF
FIGURE 39. THERMOCOUPLE MEASUREMENT APPLICATION
10nF
ISL26132, ISL26134
0.1µF
16
12
14
13
15
11
VREF+
AIN+1
AIN-1
AIN+2
AIN-2
VREF-
AVDD
AGND
18
17
XTALIN/CLOCK
XTALOUT
SDO/RDY
DVDD
DGND
SPEED
GAIN1
GAIN0
PDWN
SCLK
TEMP
1
2, 5, 6
A0
20
19
24
23
22
4
3
21
8
7
4.9152
MHz
CONTROLLER
0.1µF
MICRO
+3V
September 9, 2011
FN6954.1