LTC3589_12 Datasheet, PDF (19/50 Pages) Linear Technology – 8-Output Regulator with Sequencing and I2C

LTC3589/LTC3589-1/
LTC3589-2
OPERATION
Table 2. Shows the I²C command register settings used
to control LDO2.
Table 2. LDO 2 Command Register Settings
COMMAND
VALUE SETTING
REGISTER[BIT]
OVEN[4]
0* Disable
1 Enable
SCR2[4]
0* Wait for Output Below 300mV Before Enable
LTC3589/LTC3589-1 1 Enable Immediately
SCR2[4]
LTC3589-2
0* Enable Immediately
1 Wait for Output Below 300mV Before Enable
VCCR[5]
0* Select Register L2DTV1 (V1) Reference
1 Select Register L2DTV2 (V2) Reference
VCCR[6]
1 Initiate Dynamic Voltage Slew
VRRCR[7-6]
00 Reference Slew Rate = 0.88mV/μs
01 Reference Slew Rate = 1.75mV/μs
10 Reference Slew Rate = 3.5mV/μs
11* Reference Slew Rate = 7mV/μs
L2DTV1[4-0]
11001* DAC Dynamic Target Voltage V1
L2DTV1[5]
0* Force PGOOD Low When Slewing
1 Normal PGOOD Operation When Slewing
L2DTV1[7]
0* Shutdown LDO2 Normally
1 Keep LDO2 Alive
L2DTV2[4-0]
11001* DAC Dynamic Target Voltage V2
* Denotes Default Power-On Value
LDO Regulator 3
LDO3 is a fixed 1.8V or 2.8V (LTC3589-1/LTC3589-2) output
regulator. LDO3 is enabled by driving pin EN_LDO34 or
EN_LD03 high or by writing command register OVEN[5]
to 1.
Table 3 shows the I²C command register settings used
to control LDO3.
Table 3. LDO 3 Command Register Settings
COMMAND
VALUE SETTING
REGISTER[BIT]
OVEN[5]
0* Disable
1 Enable
SCR2[5]
0* Wait for Output Below 300mV Before Enable
LTC3589/LTC3589-1 1 Enable Immediately
SCR2[5]
LTC3589-2
0* Enable Immediately
1 Wait for Output Below 300mV Before Enable
* Denotes Default Power-On Value
LDO Regulator 4
LDO4 has four output voltage options that are controlled
by the contents of command register bits L2DTV2[6]
and L2DTV2[5]. When pin EN_LDO34 is low, LDO3 and
LDO4 are controlled by writing to command register
bits OVEN[5] and OVEN[6] respectively. By default, the
LTC3589 pin EN_LDO34 enables and disables LDO3
and LDO4 simultaneously when command register bits
OVEN[5] and OVEN[6] are low. When command register
bit L2DTV2[7] is high, control of LDO4 is disconnected
from pin EN_LDO34 and controlled by command register
bit OVEN[6] regardless of the status of EN_LDO34. The
LTC3589-1/LTC3589-2 pin EN_LDO3 enables only LDO3.
Control of LDO4 on the LTC3589-1/LTC3589-2 is under
I²C control only. Table 4 shows the I²C command register
settings that control LDO4.
Table 4. LTC3589 LDO4 Command Register Settings
COMMAND
VALUE SETTING
REGISTER[BIT]
OVEN[6]
0* Disable
1 Enable
SCR2[6]
0* Wait for Output Below 300mV Before Enable
1 Enable Immediately
L2DTV2[6-5]
L2DTV2[7]
00* V_LDO4 = 2.8V
01 V_LDO4 = 2.5V
10 V_LDO4 = 1.8V
11 V_LDO4 = 3.3V
0* LDO4 Enable Controlled by EN_LDO34
1 LDO4 Enable Controlled by OVEN[6]
LTC3589-1/LTC3589-2 LDO4 Command Register Settings
OVEN[6]
0* Disable
1 Enable
SCR2[6]
LTC3589-1
0* Wait for Output Below 300mV Before Enable
1 Enable Immediately
SCR2[6]
LTC3589-2
0* Enable Immediately
1 Wait for Output Below 300mV Before Enable
L2DTV2[6-5]
L2DTV2[7]
00* V_LDO4 = 1.2V
01 V_LDO4 = 1.8V
10 V_LDO4 = 2.5V
11 V_LDO4 = 3.2V
0* Unused
1
* Denotes Default Power-On Value
3589fe
19