LTC3589HUJ#PBF Linear Technology, LTC3589HUJ#PBF Datasheet - Page 31

• Manufacturer Part Number: LTC3589HUJ#PBF
• Description: IC DC/DC CONV 8-OUTPUT 40QFN
• Manufacturer: Linear Technology

Specifications of LTC3589HUJ#PBF

• Applications: Handheld/Mobile Devices
• Current - Supply: 8µA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: *
• Primary Input Voltage: 5.5V
• No. Of Outputs: 8
• Output Voltage: 5V
• Output Current: 1.6A
• No. Of Pins: 40
• Operating Temperature Range: -40°C To +150°C
• Msl: MSL 1 - Unlimited
• No. Of Ldo Regulators: 3
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

OPERATION
Keep-Alive Operation
For systems which require an active supply rail when in
system standby, any of the three LTC3589/LTC3589-1
step-down switching regulators or LDO2 may be kept
alive regardless of the status of PWR_ON and WAKE.
Writing a 1 to a regulator’s keep-alive bit in its dynamic
target voltage register will keep a regulator alive when the
LTC3589/LTC3589-1 is in standby mode. A regulator with
its keep-alive bit set will stay enabled until the bit is reset
writing the bit LOW, resetting the LTC3589/LTC3589-1
with a pushbutton hard reset, or a fault condition (UVLO,
PGOOD, timeout or thermal shutdown) occurs. PGOOD
and fault status are reported in the IRQSTAT and PGSTAT
registers and on the IRQ and PGOOD pins for keep-alive
regulators when PWR_ON and WAKE are LOW.
Software Control Mode
Once a power-up sequence is completed each regulator
may be enabled and disabled individually by the system
as needed for power mode requirements. Setting the out-
put voltage enable command register bit OVEN[7] HIGH
disconnects each regulator from its enable pin so control
is solely through the OVEN command register. To enter
software control mode, set command bit OVEN[7] HIGH
and the desired enable bits in OVEN[6:0] HIGH. Any of the
regulators enabled in OVEN[6:0] will stay on regardless of
the state of their enable pins when OVEN[7] is HIGH. Set-
ting the regulator enable bits and the software control bit in
OVEN[7] may occur on the same I
normal shutdown using PWR_ON resets all eight bits of the
OVEN register to 0x00 to ensure all regulators are shut off.
WAKE
LDO2
LDO3
LDO4
V1
V3
V2
V4
0.5V
0.5V
Figure 12. Pin-Strap Sequencing Timing
200μs
200μs
200μs
2
C start-stop sequence. A
1.2V
1V
1.8V
3.3V
1.2V
1.8V
2.8V
3589 F12
FAULT DETECTION, SHUTDOWN, AND REPORTING
The LTC3589/LTC3589-1 monitors V
and internal die temperature. A warning condition is indicated
when V
ture approaches the thermal shutdown temperature. A fault
condition occurs when V
output is 8% low for 14ms, or the internal die temperature
is HIGH. Warning and fault states are reported via the IRQ,
PGOOD, and RTSO pins. Specific fault states are read via
the I
RSTO Pin Function
The RSTO (reset output) pin is an open-drain output for use
as a power-on reset signal. It is pulled LOW at initial power
until LDO1 is within 8% of its target and the initial one second
start-up timer is finished. RSTO remains HIGH during normal
operation and will be pulled low if LDO1 loses regulation for
more than 25μs or a pushbutton hard reset is initiated. RSTO
is released high 14ms after LDO1 returns to regulation.
Figure 13 shows a initial power-up for the RSTO pin. If V
is not above its undervoltage thresholds at the end of the 1
second start-up time, the IRQ pin will be pulled LOW and an
undervoltage bit will be set in the IRQSTAT status register.
Figure 13. Initial Power-Up and LDO1 Undervoltage RSTO Timing
2
C serial port status registers IRQSTAT and PGSTAT.
LDO1
RSTO
LDO1
RSTO
IN
V
V
IN
IN
is less than 2.9V and when internal die tempera-
2.7V
–8%
–8%
INITIAL POWER-UP
INITIAL POWER-UP
LTC3589/LTC3589-1
1 SEC
14ms
IN
LTC3589-1
LTC3589
is less than 2.6V, any regulator
25μs
25μs
LDO1 UNDERVOLTAGE
LDO1 UNDERVOLTAGE
IN
, output rail voltages
14ms
14ms
31
3589 F13
3589fc
IN