LTC3545-1_15 Datasheet, PDF (3/20 Pages) Linear Technology – Triple 800mA Synchronous Step-Down Regulator–2.25MHz

LTC3545/LTC3545-1
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = PV_IN = 3.6V unless otherwise noted. (Note 3)
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
V_LOADREG Output Voltage Load Regulation (Notes 5, 6)
0.5
%
I_FBx
Feedback Pin Leakage (Note 5)
80
nA
I_S
Input DC Bias Current (All Regulators Enabled) I_LOAD = 0A, 2.25MHz
Pulse Skip (Active Mode)
V_FBx = 0.5V
Burst Mode Operation (All Regulators Sleeping) V_FBx = 0.7V
Shutdown (RUN_X = 0V)
680
750
μA
58
70
μA
0.1
2.0
μA
f_OSC
Oscillator Frequency
● 1.8
2.25
2.7
MHz
f_SYNC
Synchronization Frequency
LTC3545 Only
●
1
3
MHz
V_RUN(HIGH) RUNx Input High Voltage
●
1
V
V_RUN(LOW) RUNx Input Low Voltage
●
0.3
V
I_RUNx
RUN Leakage Current
±0.1
±1
μA
I_LSWx
SWx Leakage
V_RUNx = 0V, V_SWx = 0V or 5.5V, V_IN = 5.5V
±0.1
±1
μA
I_SYNC
SYNC Leakage
V_RUN = 0V, V_SYNC = 0V or 5.5V,
V_IN = 5.5V
±0.1
±1
μA
T_PGOODx
Power Good Threshold–Deviation From V_FB
Steady State (0.6V)
V_FBx Ramping Up
V_FBx Ramping Down
–7.5
%
–10
%
R_PGOODx Power Good Pull-Down On-Resistance
I_PGD = 50mA
●
14
50
Ω
MODE/SYNC Thresholds
0.93
V
Individual Regulator Characteristics (One Regulator Enabled)
t_SS
I_PK
I_Q
R_PFET
R_NFET
V_UVLO
Soft-Start Period
Peak Switch Current Limit
Input DC Bias Current
Pulse Skip (Active Mode)
Burst Mode Operation (Sleeping)
R_DS(ON) of P-Channel FET (Note 7)
R_DS(ON) of N-Channel FET (Note 7)
Undervoltage Lockout
V_FBx = 10% to 90% Fullscale
I_LOAD = 0A, 2.25MHz
V_FBx = 0.5V
V_FBx = 0.7V
I_SWx = 100mA
I_SWx = –100mA
(High V_CC to Low)
850 1100
μs
1
1.3
1.6
A
310
μA
31
μA
0.35
Ω
0.35
Ω
●
1.8
2.25
V
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 LTC3545E/LTC3545E-1 are guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3545I/LTC3545I-1 are guaranteed to meet performance specifications
over the full –40°C to 125°C operating junction temperature range.
Note 3: T_J is calculated from the ambient temperature T_A and power
dissipation P_D according to the following formula:
T_J = T_A + (P_D)(68°C/W)
This IC includes overtemperature protection that is intended to protect
the device during momentary overload conditions. Junction temperature
will exceed 125°C when overtemperature is active. Continuous operation
above the specified maximum operating junction temperature may impair
device reliability.
Note 4: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 5: The LTC3545/LTC3545-1 are tested in a proprietary test mode that
connects V_FB to the output of the error amplifier.
Note 6: Load regulation is inferred by measuring the regulation loop gain.
Note 7: The QFN switch-on resistance is guaranteed by correlation to
water level measurements.
Note 8: Guaranteed by long-term current density limitations.
35451fb
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