AD7457 Analog Devices, AD7457 Datasheet - Page 7

• Manufacturer Part Number: AD7457
• Description: Pseudo Differential Input, 100 kSPS, 12-Bit ADC in 8-Lead SOT-23
• Manufacturer: Analog Devices

Specifications of AD7457

• Resolution (bits): 12bit
• # Chan: 1
• Sample Rate: 100kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (Vref) p-p
• Adc Architecture: SAR
• Pkg Type: SOT

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 4. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
Mnemonic
V
SCLK
SDATA
CS
GND
V
V
V
DD
IN–
IN+
REF
Description
Power Supply Input. V
10 µF tantalum capacitor.
Serial Clock. Logic input. SCLK provides the serial clock for accessing data from the part. This clock input is also
used as the clock source for the conversion process.
Serial Data. Logic output. The conversion result from the AD7457 is provided on this output as a serial data
stream. The bits are clocked out on the falling edge of the SCLK input. The data stream of the AD7457 consists of
four leading zeros followed by the 12 bits of conversion data that are provided MSB first. The output coding is
straight (natural) binary.
Chip Select. This input provides the dual function of powering up the device and initiating a conversion on the
AD7457.
Analog Ground. Ground reference point for all circuitry on the AD7457. All analog input signals and any external
reference signal should be referred to this GND voltage.
Inverting Input. This pin sets the ground reference point for the V
provide a pseudo ground.
Noninverting Analog Input.
Reference Input for the AD7457. An external reference in the range 100 mV to V
The specified reference input is 2.5 V. This pin should be decoupled to GND with a capacitor of at least 0.33 µF.
DD
is 2.7 V to 5.25 V. This supply should be decoupled to GND with a 0.1 µF capacitor and a
Figure 4. 8-Lead SOT-23 Pin Configuration
SDATA
SCLK
V
CS
DD
Rev. A | Page 7 of 20
1
2
3
4
(Not to Scale)
AD7457
TOP VIEW
8
7
6
5
V
V
V
GND
REF
IN+
IN–
IN+
input. Connect to ground or to a dc offset to
DD
must be applied to this input.
AD7457