English
Language : 

LTC3788 Datasheet, PDF (4/32 Pages) Linear Technology – 2-Phase, Dual Output Synchronous Boost Controller
◁
LTC3788
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at TA = 25°C, VBIAS = 12V, unless otherwise noted (Note 2).
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
DFMAX(BG1,2) Maximum BG Duty Factor
96
%
tON(MIN)
Minimum BG On-Time
(Note 7)
110
ns
INTVCC Linear Regulator
VINTVCCVIN
Internal VCC Voltage
6V < VBIAS < 38V, VEXTVCC = 0V
5.2
5.4
5.6
V
VLDOVIN
INTVCC Load Regulation
ICC = 0mA to 50mA, VEXTVCC = 0V
0.5
2
%
VINTVCCEXT
Internal VCC Voltage
VEXTVCC = 6V
5.2
5.4
5.6
V
VLDOEXT
INTVCC Load Regulation
ICC = 0mA to 40mA, VEXTVCC = 6V
0.5
2
%
VEXTVCC
EXTVCC Switchover Voltage
EXTVCC Ramping Positive
4.5
4.8
5
V
VLDOHYS
EXTVCC Hysteresis
250
mV
Oscillator and Phase-Locked Loop
fPROG
Programmable Frequency
RFREQ = 25k
105
kHz
RFREQ = 60k
335
400
465
kHz
RFREQ = 100k
760
kHz
fLOW
Lowest Fixed Frequency
VFREQ = 0V
320
350
380
kHz
fHIGH
Highest Fixed Frequency
VFREQ = INTVCC
485
535
585
kHz
fSYNC
Synchronizable Frequency
PLLIN/MODE = External Clock
l 75
850
kHz
PGOOD1 and PGOOD2 Outputs
VPGL
IPGOOD
VPG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
IPGOOD = 2mA
0.2
0.4
V
VPGOOD = 5V
±1
μA
VFB with Respect to Set Regulated Voltage
VFB Ramping Negative
–12
–10
–8
%
Hysteresis
2.5
%
tPGOOD(DELAY) PGOOD Delay
BOOST1 and BOOST2 Charge Pump
VFB Ramping Positive
Hysteresis
PGOOD Going High to Low
8
10
12
%
2.5
%
25
μs
IBOOST1,2
BOOST Charge Pump Available
Output Current
VSW1,2 = 12V; VBOOST1,2 – VSW1,2 = 4.5V;
FREQ = 0V, Forced Continuous or
Pulse-Skipping Mode
55
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 LTC3788E is guaranteed to meet 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 LTC3788I is guaranteed over the full
–40°C to 125°C operating junction temperature range.
Note 3: TJ is calculated from the ambient temperature TA and power
dissipation PD according to the formula: TJ = TA + (PD • 34°C/W)
Note 4: The LTC3788 is tested in a feedback loop that servos VFB to the
output of the error amplifier while maintaining ITH 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.
3788f
4
 ▷