LTC4449 datasheet(33/108 Pages) LINER

33 / 108 page

LTC3882-1

Rev A

For more information www.analog.com

OPERATION

Global addressing provides a means for the bus master

to communicate with all LTC3882-1 devices on the bus

simultaneously. The LTC3882-1 global addresses of 0x5A

and 0x5B cannot be changed or disabled. Commands sent

to address 0x5A are applied to both channels, as if the

PAGE command were set to 0xFF. Global address 0x5B is

paged, allowing channel-specific control of all LTC3882-1

devices on the bus. Other LTC device types may respond

at one or both of these global addresses. Reading from

global addresses is strongly discouraged.

Rail addressing provides a means for the bus master to

simultaneously communicate with all channels connected

together to produce a single output voltage (PolyPhase).

While similar to global addressing, the rail address can

be dynamically assigned with the paged MFR_RAIL_AD-

DRESS command, allowing for any logical grouping of

channelsthatmightberequiredforreliablesystemcontrol.

Rail addresses should be unique for each single-phase or

PolyPhase rail. Different voltage rails should not attempt

to share a rail address. Reading from rail addresses is

also strongly discouraged.

Device addressing is the most common means used by a

bus master to communicate with an LTC3882-1. The value

of the device address is set by the combination of ASEL

pin programming and the MFR_ADDRESS command.

Refer to the previous section on Resistor Configuration

Pins for details.

Individual channel addressing allows the bus master to

communicate directly with a specific LTC3882-1 PWM

channel without first using a PAGE command. Refer to

the PAGE_PLUS commands for additional details.

Use of any of the four types of addressing requires careful

planning to avoid address-related bus conflicts. Commu-

nication to LTC3882-1 devices at global and rail addresses

should be limited to command write operations.

Figure 4. Quick Command Protocol

Figure 5. Send Byte Protocol

Figure 6. Send Byte Protocol with PEC

Figure 3. PMBus Packet Protocol Diagram Element Key

38821 F03

START CONDITION

REPEATED START CONDITION

READ (BIT VALUE OF 1)

WRITE (BIT VALUE OF 0)

ACKNOWLEDGE (BIT SHOULD BE 0), OR

NOT ACKNOWLEDGE (BIT SHOULD BE 1)

STOP CONDITION

PEC PACKET ERROR CODE

MASTER TO SLAVE

SLAVE TO MASTER

CONTINUATION OF PROTOCOL

...

SLAVE ADDRESS Rd/Wr A P

38821 F04

1 1

SLAVE ADDRESS

COMMAND CODE

Wr A

A P

38821 F05

1 1

SLAVE ADDRESS

COMMAND CODE

PEC

Wr A

A P

38821 F06

1 1

LTC4449 Datasheet(PDF) 33 Page - Linear Technology

LTC4449 Datasheet(HTML) 33 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL