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AD7952BCPZ

14-Bit, 1 MSPS, Differential, Programmable Input PulSAR® ADC

Analog Devices 

AD7952

MODES OF OPERATION

The AD7952 features three modes of operation: warp, normal,

and impulse. Each of these modes is more suitable to specific

applications. The mode is configured with the input pins, WARP

and IMPULSE, or via the configuration register. See Table 6 for

the pin details and the Hardware Configuration section and

Software Configuration section for programming the mode

selection with either pins or configuration register. Note that

when using the configuration register, the WARP and IMPULSE

inputs are don’t cares and should be tied to either high or low.

Warp Mode

Setting WARP = high and IMPULSE = low allows the fastest

conversion rate up to 1 MSPS. However, in this mode, the full

specified accuracy is guaranteed only when the time between

conversions does not exceed 1 ms. If the time between two

consecutive conversions is longer than 1 ms (after power-up),

the first conversion result should be ignored because in warp mode,

the ADC performs a background calibration during the SAR

conversion process. This calibration can drift if the time between

conversions exceeds 1 ms, thus causing the first conversion to

appear offset. This mode makes the AD7952 ideal for applications

where both high accuracy and fast sample rate are required.

Normal Mode

Setting WARP = IMPULSE = low or WARP = IMPULSE = high

allows the fastest mode (800 kSPS) without any limitation on

time between conversions. This mode makes the AD7952 ideal

for asynchronous applications, such as data acquisition systems,

where both high accuracy and fast sample rate are required.

Impulse Mode

Setting WARP = low and IMPULSE = high uses the lowest power

dissipation mode and allows power saving between conversions.

The maximum throughput in this mode is 670 kSPS, and in this

mode, the ADC powers down circuits after conversion, making

the AD7952 ideal for battery-powered applications.

Data Sheet

TRANSFER FUNCTIONS

Using the OB/2C digital input or via the configuration register,

the AD7952 offers two output codings: straight binary and twos

complement. See Figure 26 and Table 7 for the ideal transfer

characteristic and digital output codes for the different analog

input ranges, VIN. Note that when using the configuration

register, the OB/2C input is a don’t care and should be tied to

either high or low.

111...111

111...110

111...101

000...010

000...001

000...000

–FSR –FSR + 1 LSB

+FSR – 1 LSB

–FSR + 0.5 LSB

+FSR – 1.5 LSB

ANALOG INPUT

Figure 26. ADC Ideal Transfer Function

TYPICAL CONNECTION DIAGRAM

Figure 27 shows a typical connection diagram for the AD7952

using the internal reference, serial data, and serial configuration

interfaces. Different circuitry from that shown in Figure 27 is

optional and is discussed in the following sections.

Table 7. Output Codes and Ideal Input Voltages

VREF = 5 V

Description

VIN = 0 V to 5 V

(10 V p-p)

VIN = 0 V to 10 V

(20 V p-p)

VIN = ±5 V

(20 V p-p)

FSR − 1 LSB

4.999695 V

9.999389 V

+4.999389 V

FSR − 2 LSB

4.999390 V

9.998779 V

+4.998779 V

Midscale + 1 LSB 2.500610 V

5.000610 V

+1.228 mV

Midscale

2.5 V

5.000000 V

0V

Midscale − 1 LSB 2.499390 V

4.999389 V

−1.228 mV

−FSR + 1 LSB

610.4 μV

1.228 mV

−4.999389 V

−FSR

0V

0V

−5 V

1 This is also the code for overrange analog input (VIN+ − VIN− above VREF − VREFGND).

2 This is also the code for overrange analog input (VIN+ − VIN− below VREF − VREFGND).

VIN = ±10 V

(40 V p-p)

+9.998779 V

+9.997558 V

+2.442 mV

0V

−2.442 mV

−9.998779 V

−10 V

Digital Output Code

Straight Binary

0x3FFF1

0x3FFE

0x2001

0x2000

0x1FFF

0x0001

0x00002

Twos Complement

0x1FFF1

0x1FFE

0x0001

0x0000

0x3FFF

0x2001

0x20002

Rev. A | Page 18 of 32

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