ADP2147ACBZ-110-R7 Analog Devices Inc, ADP2147ACBZ-110-R7 Datasheet - Page 12

• Manufacturer Part Number: ADP2147ACBZ-110-R7
• Description: IC REG BUCK 800MA 3MHZ 6WLSCP
• Manufacturer: Analog Devices Inc
• Series: -r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of ADP2147ACBZ-110-R7

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 1.275V, 0.981V
• Current - Output: 800mA
• Frequency - Switching: 3MHz
• Voltage - Input: 2.3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-UFBGA, WLCSP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: ADP2147ACBZ-110-R7TR

ADP2147
SIMPLE DYNAMIC VOLTAGE SCALING (DVS)
The ADP2147 has a VSEL pin that allows the user to force the
output voltage to change from one level (the default VOUT
setting) when VSEL is low and to another level (the alternate
VOUT setting) when VSEL is high. Transition between VOUT
levels is achieved within 40 μs when VOUT is commanded to go
from a lower voltage to a higher voltage. When VOUT is com-
manded to go from a higher VOUT voltage to a lower one, the
transition time depends on the load current present at that time.
SHORT-CIRCUIT PROTECTION
The ADP2147 includes frequency foldback to prevent output
current runaway on a hard short. When the voltage at the
feedback pin falls below half the target output voltage, indi-
cating the possibility of a hard short at the output, the switching
frequency is reduced to half the internal oscillator frequency.
The reduction in the switching frequency allows more time for
the inductor to discharge, preventing a runaway of output current.
UNDERVOLTAGE LOCKOUT
To protect against battery discharge, undervoltage lockout
(UVLO) circuitry is integrated on the ADP2147. If the input
voltage drops below the 2.15 V UVLO threshold, the ADP2147
shuts down, and both the power switch and the synchronous
rectifier turn off. When the voltage rises above the UVLO
threshold, the soft start period is initiated, and the part is
enabled.
THERMAL PROTECTION
In the event that the ADP2147 junction temperature rises above
150°C, the thermal shutdown circuit turns off the regulator.
Extreme junction temperatures can be the result of high current
operation, poor circuit board design, or high ambient temperature.
A 20°C hysteresis is included so that when thermal shutdown
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occurs, the ADP2147 does not return to operation until the on-
chip temperature drops below 130°C. When coming out of
thermal shutdown, a soft start is initiated.
SOFT START
The ADP2147 has an internal soft start function that ramps the
output voltage in a controlled manner upon startup, thereby
limiting the inrush current. The soft start minimizes input
voltage drop when a battery or a high impedance power source is
connected to the regulator’s input.
After the EN pin is driven high, internal circuits begin to power
up. Start-up time in the ADP2147 is the measure of when the
output is in regulation after the EN pin is driven high. Start-up
time consists of the power-up time plus the soft start time.
CURRENT LIMIT
The ADP2147 has protection circuitry to limit the amount of
positive current flowing through the PFET switch and the
synchronous rectifier. The positive current limit on the power
switch controls the amount of current that can flow from the
power source to the output. The negative current limit prevents
the inductor current from reversing direction and flowing out
of the load.
100% DUTY OPERATION
With a drop in V
eventually reaches a limit where, even with the pFET switch on
100% of the time, V
At this limit, the ADP2147 smoothly transitions to a mode
where the PFET switch stays on 100% of the time. When the input
conditions change again and the required duty cycle falls, the
ADP2147 immediately restarts PWM regulation without
allowing overshoot on V
IN
or with an increase in I
OUT
drops below the desired output voltage.
OUT
.
LOAD
, the ADP2147