LTC3786_15 Datasheet, PDF (4/34 Pages) Linear Technology – Low IQ Synchronous Boost Controller

LTC3786
Electrical Characteristics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_BIAS = 12V, unless otherwise noted (Note 2).
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
INTV_CC Linear Regulator
V_INTVCC(VIN) Internal V_CC Voltage
V_LDO INT
INTV_CC Load Regulation
Oscillator and Phase-Locked Loop
6V < VBIAS < 38V
I_CC = 0mA to 50mA
5.2
5.4
5.6
0.5
2
f_PROG
f_LOW
f_HIGH
f_SYNC
Programmable Frequency
Lowest Fixed Frequency
Highest Fixed Frequency
Synchronizable Frequency
R_FREQ = 25k
R_FREQ = 60k
R_FREQ = 100k
V_FREQ = 0V
V_FREQ = INTV_CC
PLLIN/MODE = External Clock
105
335
400
465
760
320
350
380
485
535
585
l 75
850
PGOOD Output
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I_PGOOD = 2mA
V_PGOOD = 5V
V_FB with Respect to Set Regulated Voltage
V_FB Ramping Negative
Hysteresis
V_FB Ramping Positive
Hysteresis
0.2
0.4
±1
–12
–10
–8
2.5
8
10
12
2.5
t_PGOOD(DELAY) PGOOD Delay
PGOOD Going High to Low
25
BOOST Charge Pump
I_BOOST
BOOST Charge Pump Available
V_SW = 12V; V_BOOST – V_SW = 4.5V;
85
Output Current
FREQ = 0V, Forced Continuous or
Pulse-Skipping Mode
UNITS
V
%
kHz
kHz
kHz
kHz
kHz
kHz
V
µA
%
%
%
%
µs
µA
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 LTC3786 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3786E is guaranteed to meet specifications from
0°C to 85°C junction temperature. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3786I is guaranteed over the –40°C to 125°C operating junction
temperature range. 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 = 68°C for the QFN package and θ_JA = 40°C for the MSOP
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 LTC3786 is tested in a feedback loop that servos V_FB to the
output of the error amplifier while maintaining I_TH at the midpoint of the
current limit range.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: see Minimum On-Time Considerations in the Applications
Information section.
3786fa
4