LTC3892_15 Datasheet, PDF (6/36 Pages) Linear Technology – 60V Low IQ, Dual, 2-Phase Synchronous Step-Down DC/DC Controller

LTC3892/LTC3892-1
Electrical Characteristics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T_A = 25°C (Note 2). V_IN = 12V, V_RUN1,2,3 = 5V, V_EXTVCC = 0V, V_DRVSET = 0V,
VPRG1 = FLOAT unless otherwise noted.
SYMBOL
PARAMETER
Oscillator and Phase-Locked Loop
PLLIN
V_OH/V_OL Levels
f_25kΩ
Programmable Frequency
f_65kΩ
Programmable Frequency
f_105kΩ
Programmable Frequency
f_LOW
Low Fixed Frequency
f_HIGH
High Fixed Frequency
f_SYNC
Synchronizable Frequency
PLLIN V_IH
PLLIN V_IL
PLLIN/MODE Input High Level
PLLIN/MODE Input Low Level
PGOOD1 and PGOOD2 Outputs (LTC3892 Only)
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
t_PG
Delay for Reporting a Fault
CONDITIONS
MIN TYP MAX UNITS
R_FREQ =25kΩ, PLLIN/MODE = DC Voltage
105
kHz
R_FREQ = 65kΩ, PLLIN/MODE = DC Voltage
375 440 505
kHz
R_FREQ = 105kΩ, PLLIN/MODE = DC Voltage
835
kHz
V_FREQ = 0V, PLLIN/MODE = DC Voltage
320 350 380
kHz
V_FREQ = INTV_CC, PLLIN/MODE = DC Voltage
485 535 585
kHz
PLLIN/MODE = External Clock
l 75
850
kHz
PLLIN/MODE = External Clock
PLLIN/MODE = External Clock
l 2.5
l
V
0.5
V
I_PGOOD = 2mA
V_PGOOD = 5V
V_FB with Respect to Set Regulated Voltage
V_FB Ramping Negative
Hysteresis
V_FB with Respect to Set Regulated Voltage
V_FB Ramping Positive
Hysteresis
0.2 0.4
V
±1
µA
–13 –10 –7
%
2.5
%
7
10
13
%
2.5
%
35
µs
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may
cause permanent damage to the device. Exposure to any Absolute Maximum
Ratings for extended periods may affect device reliability and lifetime.
Note 2: The LTC3892/LTC3892-1 is tested under pulsed load conditions
such that T_J ≈ T_A. The LTC3892E/LTC3892E-1 is 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 LTC3892I/LTC3892I-1 is guaranteed over the –40°C to 125°C
operating junction temperature range, the LTC3892H/LTC3892H-1 is
guaranteed over the –40°C to 150°C operating junction temperature
range, and the LTC3892MP/LTC3892MP-1 is tested and guaranteed over
the –55°C to 150°C operating junction temperature range. High junction
temperatures degrade operating lifetimes; operating lifetime is derated
for junction temperatures greater than125°C. 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 • θ_JA)
where θ_JA = 44°C/W for the QFN package and where θ_JA = 30°C/W for the
TSSOP package.
Note 3: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
Note 4: The LTC3892/LTC3892-1 is tested in a feedback loop that
servos V_ITH1,2 to a specified voltage and measures the resultant V_FB1,2.
The specification at 85°C is not tested in production and is assured by
design, characterization and correlation to production testing at other
temperatures (125°C for the LTC3892E/LTC3892E-1 and LTC3892I/
LTC3892I-1, 150°C for the LTC3892H/LTC3892H-1 and LTC3892MP/
LTC3892MP-1). For the LTC3892I/LTC3892I-1 and LTC3892H/
LTC3892H-1, the specification at 0°C is not tested in production and is
assured by design, characterization and correlation to production testing
at –40°C. For the LTC3892MP/LTC3892MP-1, the specification at 0°C is
not tested in production and is assured by design, characterization and
correlation to production testing at –55°C.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels
Note 7: The minimum on-time condition is specified for an inductor
peak-to-peak ripple current >40% of I_MAX (See Minimum On-Time
Considerations in the Applications Information section)
Note 8: Do not apply a voltage or current source to these pins. They must be
connected to capacitive loads only, otherwise permanent damage may occur.
38921f
6
For more information www.linear.com/LTC3892