ADP5023 Analog Devices, ADP5023 Datasheet - Page 18

• Manufacturer Part Number: ADP5023
• Description: Dual 3 MHz, 800 mA Buck Regulator with One 300 mA LDO
• Manufacturer: Analog Devices

ADP5023
operation, poor circuit board design, or high ambient
temperature. A 20°C hysteresis is included so that when thermal
shutdown occurs, the regulators do not return to operation until
the on-chip temperature drops below 130°C. When coming out
of thermal shutdown, all regulators restart with soft-start
control.
Undervoltage Lockout
To protect against battery discharge, undervoltage lockout
(UVLO) circuitry is integrated into the system. If the input
voltage on VIN1 drops below a typical 2.15 V UVLO threshold,
all channels shut down. In the buck channels, both the power
switch and the synchronous rectifier turn off. When the voltage
on VIN1 rises above the UVLO threshold, the part is enabled
once more.
Alternatively, the user can select device models with a UVLO
set at a higher level, suitable for USB applications. For these
PULL-DOWNS
BUCK1, LDO1
PULL-DOWN
BUCK2
VOUT1
VOUT3
VOUT2
AVIN
30µs (MIN)
50µs (MIN)
Figure 46. Regulator Sequencing on
Rev. A | Page 18 of 28
ADP5023
models, the device reaches the turn-off threshold when the
input supply drops to 3.65 V typical.
In case of a thermal or UVLO event, the active pull-downs (if
factory enabled) are enabled to discharge the output capacitors
quickly. The pull-down resistors remain engaged until the thermal
fault event is no longer present, or the input supply voltage falls
below the V
imately 1 V.
Enable/Shutdown
The
A logic level high applied to the ENx pin activates a regulator,
whereas a logic level low turns off a regulator.
Figure 46 shows the regulator activation timings for the
ADP5023
shown is the active pull-down activation.
(
ADP5023
EN1 = EN2 = EN3
VUVLO
when all enable pins are connected to AVIN. Also
POR
voltage level. The typical value of V
has an individual control pin for each regulator.
= V
AVIN
VPOR
)
30µs (MIN)
50µs (MIN)
Data Sheet
POR
is approx-