SPT7937SIR 查看數據表（PDF） - Unspecified

零件编号

产品描述 (功能)

比赛名单

SPT7937SIR

12-BIT, 28 MSPS, 170 mW A/D CONVERTER

Unspecified 

Figure 2 – Typical Interface Circuit

CLK IN

+

+A5

+

AIN

+A5

U1

+

TK11240B

Ext VREF

(+4 V)

OGND

DGND

OTR

D11

Out of Range Bit

MSB

CLK

D10

DVDD

D9

AVDD

D8

DGNUD1

D7

(DUT)

VINR

D6

VIN

D5

RGND

D4

VRHS

D3

VRHF

D2

VRLF

D1

VRLS

D0

LSB

28 DVDD2 OVDD 1

FB

+D3/5V

+D3/5V

+A5

+D3/5

+

10 µF

+

10 µF

+A5 AGND

Notes:

1) Unless otherwise specified, all non-polarized capacitors are 0.01 microfarad

surface-mount chip capacitors. They need to be placed as close to the pin as possible

2) All polarized capacitors are 4.7 to 10 microfarad tantalum surface-mount capacitors

3) FB is a ferrite bead. Place FB as close to the DUT as possible

4) U1 is TOKO regulator TK11240B (4.0 V)

+D3/5

DGND

TYPICAL INTERFACE CIRCUIT

Very few external components are required to achieve the

stated device performance. Figure 2 shows the typical inter-

face requirements when using the SPT7937 in normal

circuit operation. The following sections provide descrip-

tions of the major functions and outline critical performance

criteria to consider for achieving the optimal device

performance.

POWER SUPPLIES AND GROUNDING

SPT suggests that both the digital (DVDD) and the analog

(AVDD) supply voltages on the SPT7937 be derived from a

single analog supply as shown in figure 2. A separate digital

supply should be used for the digital output driver supply

(OVDD) and all interface circuitry. SPT suggests using this

power supply configuration to prevent a possible latch-up

condition on power up. In addition, the power supplies must

be powered up before the analog input is applied.

SPT

6

SPT7937

1/14/00

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