Selecting SPI Clock Modes for Interfacing the MAX1132 ADC with the MAXQ2000 Microcontroller

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Note: The suffix "-bar" (CS-bar) indicates the active-low functionality of the CS pin.

MAX1132 Overview

The MAX1132 is a 200ksps, 16-bit ADC. The MAXQ2000 can interface with the MAX1132 in a variety of SPI clock modes: 8-bit, 16-bit, or a combination of both. To maximize the performance of the ADC, it is important to determine which mode to use during early stages of development. It is obvious that a 16-bit ADC with 16 clock frames should use 16-bit mode; however, in a scenario where the ADC uses 24 clock frames, the SPI clock mode must be evaluated closely. This application note provides test results for 8-bit mode, 16-bit mode, and combination mode; the results indicate that combination mode is optimal when the MAX1132 uses 24 clock frames.

Hardware Overview

This application circuit utilizes the MAX1132EVKIT and MAXQ2000-KIT.
Figure 1 presents the MAX1132 EV kit schematic, and Figure 2 illustrates the configuration of the system. To interface the MAX1132 EV kit with the MAXQ2000-KIT, connect SCLK, CS-bar, DOUT, and DIN from the MAX1132 EV kit to the MAXQ2000-KIT, as shown in Figure 2. In addition, a +5V supply is applied on the AVDDand AGND terminals of the EV kit. JU1 of the EV kit must be installed on 1–2 (ON) position. Apply an analog signal up to +12V on JU2, and the rest of the jumpers are left open. SW3 of the MAXQ2000-KIT must be turned off for proper operation of the system.
Figure 1. The schematic for the MAX1132 EV kit.
Figure 1. The schematic for the MAX1132 EV kit.


Designed, Built, Tested

Board pictured here has been fully assembled and tested. Not available for sale.


Maxim Devices (2)

Part Number Name Product Family Order Design kits and evaluation modules
MAX1132 16-Bit ADC, 200ksps, 5V Single-Supply with Reference Analog-to-Digital Converters Buy Now Design Kits
MAXQ2000 Low-Power LCD Microcontroller MCU - Microcontroller Buy Now Design Kits

Maxim Devices (2)

Part Number Product Family
Analog-to-Digital Converters
16-Bit ADC, 200ksps, 5V Single-Supply with Reference
MCU - Microcontroller
Low-Power LCD Microcontroller

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