LT3582 LINER [Linear Technology], LT3582 Datasheet - Page 12

• Manufacturer Part Number: LT3582
• Description: I2C Programmable Boost and Single Inductor Inverting DC/DC Converters with OTP
• Manufacturer: LINER [Linear Technology]

LT3582/LT3582-5/LT3582-12
APPLICATIONS INFORMATION
CMDR register. All data written to register addresses 0-2
is stored in REGO-REG2. Regardless of the RSEL bits, OTP
bytes cannot be written directly. See the OTP Program-
ming section for more information.
Data Transfer Protocol
The LT3582 series supports 8-bit data transfers in the
transaction formats shown in Figures 2 and 3 below.
Multiple data bytes can only be transferred by issuing
multiple transactions.
Figure 2 shows the required format for writing a byte of
data to the LT3582 series. Again, the chip address depends
on the CA pin logic state.
A byte of data is read from the LT3582 series using the
format shown in Figure 3. This transaction requires four
I
repeated for each subsequent byte of data that is read.
12
2
S
S
C bytes to read one byte of chip data and must be
FROM MASTER TO SLAVE
FROM SLAVE TO MASTER
0110 001 OR
0110 001 OR
CHIP ADDR
CHIP ADDR
1000 101
1000 101
S
Figure 2: I
Figure 3: I
0110 001 OR
CHIP ADDR
1000 101
W
W
0
0
2
2
C Byte Write Transaction
A
A
C Byte Read Transaction
0
0
00000b2:b0
00000b2:b0
REG ADDR
REG ADDR
R
1
A: ACKNOWLEDGE (LOW)
A: NOT ACKNOWLEDGE (HIGH)
R: READ BIT (HIGH)
W WRITE BIT (LOW)
S: START CONDITION
P: STOP CONDITION
A
0
DATA
b7:b0
A
0
A
0
DATA
b7:b0
A
1
A
0
P
P
LT3582 Chip Confi guration
Settings such as output voltages and sequencing are
digitally programmable. The chip uses settings from either
the REG or OTP bytes, depending on the states of the cor-
responding RSEL bits (0 for OTP and 1 for REG).
During shutdown the RSEL bits are reset low. As a result,
the initial confi guration comes from the OTP data bytes.
After power-up, the confi guration can be changed by writ-
ing new settings to the appropriate REG data byte(s) then
setting the corresponding RSEL bit(s).
Finally, data in the REG bytes can be permanently pro-
grammed to OTP by applying voltage to the V
setting the WOTP bit in the Command Register. See the
OTP Programming section for more information.
LT3582-5/LT3582-12 Chip Confi guration
The LT3582-5/LT3582-12 are shipped from the factory
with the OTP memory pre-programmed and LOCKed which
prohibits subsequent changes to the confi guration. The
confi guration can still be read through the I
the RST & SWOFF bits of the CMDR register (described
later) are functional. The following sections describe the
various confi gurable features of the LT3582. The LT3582-5
and LT3582-12 are pre-confi gured as follows: V
are programmed for ±5V or ±12V respectively, LOCK = 1,
IRMP = 00, PDDIS = 1, PUSEQ = 11 and V
or 0. Since LOCK = 1, subsequent confi guration changes
are prohibited. See Confi guration Lockout (LOCK Bit) for
more information.
Registers and OTP
The registers and OTP bytes for the LT3582 series are
organized as shown in Table 1. The CMDR is reset to 00h
upon power up, during shutdown and during under-volt-
age and thermal lockouts. REG0-REG2 are never reset
and must always be loaded with valid data before use.
The LT3582’s OTP memory is shipped with all 0’s, and
as a result, the PUSEQ bits are confi gured to disable the
outputs. The PUSEQ bits must be reconfi gured to enable
the outputs.
PLUS
2
C bus and
PP
may be 1
P
pin and
and V
3582512f
N