DtHD

Valid Data

DtSUD

DtPLD

DtPHD

Valid Data

16

th clock

SCLK

SDI

SVA-30206510

LMH6523

www.ti.com

SNOSC88 – DECEMBER 2012

Figure 55. Write Timing – Data Written to SDI Pin

Table 5. Write Timing Data Input on SDI Pin

PARAMETER

DESCRIPTION

tPL

Minimum clock low time (clock duty dycle)

tPH

Minimum clock high time (clock duty cycle)

tSU

Input data setup time

tH

Input data hold time

Table 6. Serial Word Format for LMH6523

C7

C6

C5

C4

C3

C2

C1

C0

1= read

0

0

0

0

000= CHA

0=write

001=CHB

010=CHC

011=CHD

100=Fast Adjust

Table 7. CH A through D Register Definition

7

6

5

4

3

2

1

0

Reserved, =0

Reserved

Reserved

Attenuation Setting:

00000 = Maximum Gain

11111 = Minimum Gain

Table 8. Fast Adjust Register Definition

7

6

5

4

3

2

1

0

CH D

CH C

CH B

CH A

Table 9. Fast Adjust Codes

CODE

ACTION

00

No Change

01

Decrease Attenuation by 1 Step (1dB)

10

Increase Attenuation by 1 Step (1dB)

11

Reserved, action undefined

THERMAL MANAGEMENT

The LMH6523 is packaged in a thermally enhanced package. The exposed pad is connected to the GND pins. It

is recommended, but not necessary, that the exposed pad be connected to the supply ground plane. In any

case, the thermal dissipation of the device is largely dependent on the attachment of this pad to the system

printed circuit board (PCB). The exposed pad should be attached to as much copper on the PCB as possible,

preferably external copper. However, it is also very important to maintain good high speed layout practices when

designing a system board. Please refer to the LMH6522 evaluation board (available separately) for suggested

layout techniques.

Copyright © 2012, Texas Instruments Incorporated

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