MAX147EVKIT-DIP Maxim Integrated Products, MAX147EVKIT-DIP Datasheet - Page 4

• Manufacturer Part Number: MAX147EVKIT-DIP
• Description: EVAL KIT FOR MAX147
• Manufacturer: Maxim Integrated Products

Specifications of MAX147EVKIT-DIP

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 133k
• Data Interface: Serial
• Inputs Per Adc: 8 Single Ended
• Input Range: ±VREF/2
• Power (typ) @ Conditions: 2.7mW @ 133kSPS
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Utilized Ic / Part: MAX147
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

MAX147 Evaluation System/Evaluation Kit
The program KIT14716.S19 demonstrates the 16-bits-
per-transfer interface scheme, which operates at 91ksps
throughput. In this demonstration,
the QSPI operates continuously in the background.
Refer to the timing diagrams in the Clock Modes section
of the MAX147 data sheet. To use this program, follow
the instructions in Quick Start , but in step 8, download
KIT14716.S19 instead of KIT147.S19. After loading,
press ALT+C to switch to the control panel.
The MAX147 EV kit software assumes a 2.5V reference
voltage, unless otherwise specified. When using a refer-
ence value other than 2.5V, specify the value when start-
ing the program. For example, if VREF is driven by a
2.048V reference, start the MAX147 software by typing:
Or, on the MAX146, if REFADJ is driven by a 1.2V refer-
ence, start the MAX147 software by typing:
The external reference’s temperature coefficient must
be 20ppm/°C or less to achieve accuracy to within four
LSBs over the 0°C to +70°C temperature range. For
12-bit accuracy over the 0°C to +70°C range, the refer-
ence’s temperature coefficient must be 4ppm/°C or less.
The MAX146 can use either its internal reference or an
external reference. On the EV kit, the internal reference
has been disabled by pulling REFADJ up to VDD (JU2)
and driving VREF with a MAX872 2.5V reference (JU5).
Table 2. Recommended QSPI Setup
Parameters for 16 Bits per Transfer
(used in KIT14716.S19)
4
PARAMETER
_______________________________________________________________________________________
CPOL
CPHA
SPBR
BITS
CR0
DTL
RR0
TR0
Changing the Reference Voltage
MAX147 146 REFADJ 1.2
5 (1.68MHz)
0 (clock is idle low)
0 (data is stable on clock rising edge)
16
4 (7.6µs delay used in internal clock mode)
0000 0001 xxxx xyy0 (configure and start
conversion)
External clock: 1100 xxx0 (16-bit transfer).
Internal clock: 1110 xxx0 (16-bit transfer
with DT delay).
Received data, left justified
MAX147 VREF 2.048
Operating with QSPI,
16 Bits per Transfer
VALUE
CS is held low and
For lowest component count, enable the MAX146’s inter-
nal reference by removing the shunts from JU2 and
JU5. This enables the internal bandgap reference and
the reference buffer, driving VREF internally to 2.5V. A
0.01µF ceramic bypass capacitor near REFADJ (C1 on
the EV kit) provides noise filtering for the bandgap
reference.
The MAX147 EV kit board includes a MAX666, config-
ured as a 3V regulator. Trim pot R16 adjusts the VDD
voltage between 2.3V and 3.6V.
The MAX872 is a micropower 2.5V reference.
The MAX494 and MAX495 are low-voltage, rail-to-rail op
amps with 500kHz gain-bandwidth product. The
MAX495 buffers the external COM input source. The
MAX494 can be used to buffer some of the input signals.
The MAX393 analog switch allows the EV kit software to
route the MAX147 COM pin to ground or to the external
COM input. In addition, the external COM input can be
routed to input channel 0. Typical systems connect
COM directly to analog ground or the analog common
voltage. The MAX393 can be powered by 3V, but if
driven by 5V logic (as is the case with the EV system), it
must be powered by 5V.
The 74HCT04 translates the DOUT and SSTRB signals
from 3V to 5V logic levels for interfacing to the µC mod-
ule. The MAX147’s logic inputs can be driven directly
from 5V logic levels.
The analog-to-digital converter (ADC) inputs require a
sufficiently low-impedance source for specified accura-
cy. An ADC can inject a small amount of charge at the
start of the acquisition time, and the source signal must
recover to within the desired accuracy before the
acquisition time ends. If the source by itself cannot do
this, use an op amp to buffer the input signal.
To buffer the CH4–CH7 input signals, unplug the 14-pin
header from U7, and install the supplied MAX494 quad
op amp in its place. Note the location of pin 1 toward
the upper right corner of the board.
When using an input buffer, the buffer output cannot
reach the power-supply rails. If the MAX494 op-amp
buffer is installed and the input to the buffer is
grounded, the buffered output will not reach
ground. The MAX494 allows its output signal to go to
within approximately 50mV of either supply.
Input-Signal Buffering
Detailed Description
of Hardware