Datasheet

LTC3589/LTC3589-1/
LTC3589-2
19
3589ff
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Table 2. Shows the I
2
C command register settings used
to control LDO2.
Table 2. LDO 2 Command Register Settings
COMMAND
REGISTER[BIT]
VALUE SETTING
OVEN[4] 0*
1
Disable
Enable
SCR2[4]
LTC3589/LTC3589-1
0*
1
Wait for Output Below 300mV Before Enable
Enable Immediately
SCR2[4]
LTC3589-2
0*
1
Enable Immediately
Wait for Output Below 300mV Before Enable
VCCR[5] 0*
1
Select Register L2DTV1 (V1) Reference
Select Register L2DTV2 (V2) Reference
VCCR[6] 1 Initiate Dynamic Voltage Slew
VRRCR[7-6] 00
01
10
11*
Reference Slew Rate = 0.88mV/µs
Reference Slew Rate = 1.75mV/µs
Reference Slew Rate = 3.5mV/µs
Reference Slew Rate = 7mV/µs
L2DTV1[4-0] 11001* DAC Dynamic Target Voltage V1
L2DTV1[5] 0*
1
Force PGOOD Low When Slewing
Normal PGOOD Operation When Slewing
L2DTV1[7] 0*
1
Shutdown LDO2 Normally
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 I
2
C command register settings used
to control LDO3.
Table 3. LDO 3 Command Register Settings
COMMAND
REGISTER[BIT]
VALUE SETTING
OVEN[5] 0*
1
Disable
Enable
SCR2[5]
LTC3589/LTC3589-1
0*
1
Wait for Output Below 300mV Before Enable
Enable Immediately
SCR2[5]
LTC3589-2
0*
1
Enable Immediately
Wait for Output Below 300mV Before Enable
* Denotes Default Power-On Value
operaTion
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
I
2
C control only. Table 4 shows the I
2
C command register
settings that control LDO4.
Table 4. LTC3589 LDO4 Command Register Settings
COMMAND
REGISTER[BIT]
VALUE SETTING
OVEN[6] 0*
1
Disable
Enable
SCR2[6] 0*
1
Wait for Output Below 300mV Before Enable
Enable Immediately
L2DTV2[6-5] 00*
01
10
11
V
LDO4
= 2.8V
V
LDO4
= 2.5V
V
LDO4
= 1.8V
V
LDO4
= 3.3V
L2DTV2[7] 0*
1
LDO4 Enable Controlled by EN_LDO34
LDO4 Enable Controlled by OVEN[6]
LTC3589-1/LTC3589-2 LDO4 Command Register Settings
OVEN[6] 0*
1
Disable
Enable
SCR2[6]
LTC3589-1
0*
1
Wait for Output Below 300mV Before Enable
Enable Immediately
SCR2[6]
LTC3589-2
0*
1
Enable Immediately
Wait for Output Below 300mV Before Enable
L2DTV2[6-5] 00*
01
10
11
V
LDO4
= 1.2V
V
LDO4
= 1.8V
V
LDO4
= 2.5V
V
LDO4
= 3.2V
L2DTV2[7] 0*
1
Unused
* Denotes Default Power-On Value