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/4-channel, ±v, Multirange inputs, serial 14-bit adcs, Mode control – Rainbow Electronics MAX1035 User Manual

Page 22

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MAX1034/MAX1035

Mode Control

The MAX1034/MAX1035 contain one byte-wide mode-
control register. The timing diagram of Figure 15 shows
how to use the mode-control byte, and the mode-con-
trol byte format is shown in Table 7. The mode-control
byte is used to select the conversion method and to
control the power modes of the MAX1034/MAX1035.

Selecting the Conversion Method

The conversion method is selected using the mode-
control byte (see the Mode Control section), and the con-
version is initiated using a conversion-start command
(Table 3, and Figures 2, 3, and 4). The MAX1034/
MAX1035 convert analog signals to digital data using one
of three methods:

External Clock Mode, Mode 0 (Figure 2)

• Highest maximum throughput (see the Electrical

Characteristics table)

• User controls the sample instant

• CS remains low during the conversion

• User supplies SCLK throughout the ADC con-

version and reads data at DOUT

External Acquisition Mode, Mode 1 (Figure 3)

• Lowest maximum throughput (see the Electrical

Characteristics table)

• User controls the sample instant

• User supplies two bytes of SCLK, then drives

CS high to relieve processor load while the
ADC converts

• After SSTRB transitions high, the user supplies

two bytes of SCLK and reads data at DOUT

Internal Clock Mode, Mode 2 (Figure 4)

• High maximum throughput (see the Electrical

Characteristics table)

• The internal clock controls the sampling instant

8-/4-Channel, ±V

REF

Multirange Inputs,

Serial 14-Bit ADCs

22

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1 LSB = FSR x V

REF

16,384 x 4.096V

BINARY OUTPUT CODE (LSB [hex])

3FFF

3FFE

3FFD

2001

2000

1FFF

0003

0002

0001

0000

FSR

0

1

2

3

8,192

16,381 16,383

INPUT VOLTAGE (LSB [DECIMAL])

(AGND1)

FSR

Figure 13. Ideal Unipolar Transfer Function, Single-Ended
Input, -FSR to 0

1 LSB = FSR x V

REF

16,384 x 4.096V

BINARY OUTPUT CODE (LSB [hex])

3FFF

3FFE

3FFD

2001

2000

1FFF

0003

0002

0001

0000

FSR

0

1

2

3

8,192

16,381 16,383

INPUT VOLTAGE (LSB [DECIMAL])

(AGND1)

FSR

Figure 14. Ideal Unipolar Transfer Function, Single-Ended
Input, 0 to +FSR

1 LSB = FSR x V

REF

16,384 x 4.096V

BINARY OUTPUT CODE (LSB [hex])

3FFF

3FFE

3FFD

2001

2000

1FFF

0003

0002

0001

0000

FSR

-8,192 -8,190

0

+8,189 +8,191

INPUT VOLTAGE (LSB [DECIMAL])

AGND1 (DIF/SGL = 0)

0V (DIF/SGL = 1)

FSR

-1

+1

Figure 12. Ideal Bipolar Transfer Function, Single-Ended or
Differential Input