LTC3554-1_15 Datasheet, PDF (6/36 Pages) Linear Technology – Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators

LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
P USHBUTTON INTERFACE Ele ctrical Characteristics The l denotes
specifications that apply over the full operating junction temperature range, otherwise specifications are at T_A = 25°C (Note 2).
V_BAT = 3.8V, unless otherwise noted.
SYMBOL
t_EXTPWR
t_{PON_UP}
t_{PON_DIS}
t_PUP
t_PDN
t_PGOODH
t_PGOODL
PARAMETER
Power-Up from USB Present to Power-Up
(PUP1 or PUP2) State
Any PWR_ONx High to Power-On State
PWR_ONx Low to Buckx Disabled
Power-Up (PUP1 or PUP2) State Duration
Power-Down (PDN1 or PDN2) State
Duration
Bucks in Regulation to PGOOD High
Bucks Disabled to PGOOD Low
CONDITIONS
Starting in the Hard Reset (HR) or Power-Off
(POFF) States
Starting with Both PWR_ONx Low in the Power-
Off (POFF) State
All Enabled Bucks within PGOOD Threshold
Voltage
All Bucks Disabled
MIN TYP MAX UNITS
100
ms
900
µs
1
µs
5
s
1
s
230
ms
100
µs
Note 1. Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3554 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3554 are guaranteed to meet specifications from
0°C to 85°C junction temperature. Specifications over the –40°C to
85°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. Note that
the maximum ambient temperature consistent with these specifications
is determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors.
The junction temperature (T_J, in °C) is calculated from the ambient
temperature (T_A, in °C) and power dissipation (P_D, in Watts) according to
the formula:
T_J = T_A + (P_D • q_JA)
where q_JA (in °C/W) is the package thermal impedance.
Note 3. This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 110°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 4. V_CC is the greater of V_BUS or BAT.
Note 5. Total Battery Drain Current is the sum of I_BATQ and I_OUT. For
example, in applications where the buck input (BVIN pin) is connected to
the PowerPath output (V_OUT pin) such that I_OUT = I_BVIN, total battery drain
current = I_BATQ + I_BVIN.
Note 6. hC/10 is expressed as a fraction of programmed full charge
current with specified PROG resistor.
Note 7. The current limit features of this part are intended to protect the
IC from short term or intermittent fault conditions. Continuous operation
above the absolute maximum specified pin current rating may result in
device degradation or failure.
Note 8. FB High, Not Switching
Note 9. V_OUT not in UVLO.
Note 10. PGOOD threshold is expressed as a percentage difference from
the buck regulation voltage. The threshold is measured with the buck
feedback pin voltage rising.
Note 11. See the Operation section of this data sheet for detailed
explanation of the pushbutton state machine and the effects of each state
on switching regulator and power manager operation.
Note 12. If V_BUS < V_UVLO then V_FWD = 0 and the forward voltage across
the ideal diode is equal to its current times R_DROPOUT.
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