ADC10D1X00 Datasheet, PDF(1/4 Page) National Semiconductor (TI) – The only difference on the pin-out between

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ADC10D1X00 Datasheet, PDF (1/4 Pages) National Semiconductor (TI) – The only difference on the pin-out between

ADC1xD1x00 Pin

Compatibility

National Semiconductor

Application Note 2128

Marjorie Plisch

March 8, 2011

In order to facilitate upgrading applications from a 10-bit Gig

ADC to a 12-bit Gig ADC, the ADC10D1x00 (ADC10D1500/

ADC10D1000) is designed to be pin-compatible with the

ADC12D1x00 (ADC12D1800/1600/1000). This means that a

single board layout may be designed with both resolution

ADCs in mind for more cost efficient and time-to-market prod-

uct development.

ADC10D1x00 vs. ADC12D1x00

The only difference on the pin-out between the

ADC10D1x00 and the ADC12D1x00 is that the

ADC12D1x00 has two additional data bits for each output da-

ta bank. Bits<11:2> for the ADC12D1x00 correspond to

Bits<9:0> for the ADC10D1x00. The placeholders for the two

additional bits for the ADC12D1x00 are labeled as RSV bits

on the ADC10D1x00. The RSV bits on the ADC10D1x00 cor-

respond to the two LSB, Bits<1:0>, on the ADC12D1x00, see

Table 1.

TABLE 1. ADC1xD1x00 LSB Pins

Ball No. ADC10D1x00 Name ADC12D1x00 Name

V10/U10

RSV7+/-

DQd1+/-

Y10/W10

RSV6+/-

DQd0+/-

W19/W20

RSV5+/-

DQ1+/-

W18/V17

RSV4+/-

DQ0+/-

B19/B20

RSV3+/-

DI1+/-

B18/C17

RSV2+/-

DI0+/-

C10/D10

RSV1+/-

DId1+/-

A10/B10

RSV0+/-

DId0+/-

Terminating RSV pins on the

ADC10D1x00

The RSV pins may be terminated in a way which makes one

board usable for both ADC10D1x00 and ADC12D1x00, see

Figure 1. On the ADC10D1x00, the RSV pins are high

impedance, so only the 100â¦ differential termination resistor

for the LVDS driver from the ADC is necessary to be com-

patible with the ADC12D1x00. However, if these pins are

terminated into an FPGA and it is necessary for them to be

forced to a known voltage, then the additional 1kâ¦ resistors

can be added to the design; the specific value of the 1kâ¦ re-

sistors may be changed based upon the requirements of the

specific FPGA. For a board which is populated with an

ADC12D1x00, the 1kâ¦ resistors should be left unpopulated.

30153301

FIGURE 1. RSV Pin Termination

Datasheet vs. Reference Board

For a few exceptions, Nationalâs Reference Board does not

follow the datasheet recommendations for certain pin con-

nections. These exceptions are listed below in Table 2. His-

torically, the exceptions exist because the Reference Board

was developed before silicon development was finalized. In

every case, it is correct to follow the datasheet recommenda-

tion. âDNCâ stands for âDo Not Connectâ and âNCâ stands for

âNot Connected.â

TABLE 2. Datasheet vs. RB Comparison

Ball No. ADC1xD1x00 National Reference Board

Datasheet Name

Connection

POREN (from FPGA)

WSS (from FPGA)

E3/F4

DNC/DNC

VTEST+/- (to header)

DNC

GND

DNC

VNEGI (shorted to J4/K2)

DNC

VNEGQ (shorted to L2/M4)

DNC

CALFAIL (to FPGA)

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