Single LNB Supply and Control Voltage Regulator

A8293

10

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

compatible interface via the 8-bit Control registers. As the A8293

contains numerous control options, it is necessary to have two

control registers. Each register contains up to 6 bits of data (bit

0 to bit 5), followed by 2 bits for the register address (bit 6 and

bit 7). The power-up states for the control functions are all 0s.

The following tables define the control bits for each address

and the settings for output voltage:

Table 1. Control Register Address (I1, I0) = 00

Bit

Name

Function

0

VSEL0

See table 3, Output Voltage Amplitude Selection

1

VSEL1

2

VSEL2

3

VSEL3

0: LNB = Low range

1: LNB = High range

4

ODT

1 (recommended): The ODT functions are always

enabled, but setting 1 recommended at all times.

5

ENB

0: Disable LNB Output

1: Enable LNB Output

6

I0

Address Bit: 0

7

I1

Address Bit: 0

Bit 0

VSEL0 These three bits provide incremental control over the voltage on the LNB output.

Bit 1

VSEL1 The available voltages provide the necessary levels for all the common standards

Bit 2

VSEL2 plus the ability to add line compensation in increments of 333 mV. The voltage

levels are defined in table 3, Output Voltage Amplitude Selection.

Bit 3

VSEL3 Switches between the low level and high level output voltages on the LNB output.

0 selects the low level voltage and 1 selects the high level. The low-level center voltage

is 12.709 V nominal and the high level is 18.042 V nominal. These may be increased

in steps of 333 mV using the VSEL2, VSEL1 and VSEL0 control register bits.

Bit 4

ODT

The overcurrent disable timer is always enabled.

Bit 5

ENB

Enables the LNB output. When set to 1 the LNB output is switched on. When set to

0, the LNB output is disabled.

Bit 6

I0

Address

Bit 7

I1

Address