LTC3788-1 Datasheet, PDF (4/28 Pages) Linear Technology – 2-Phase, Dual Output Synchronous Boost Controller

LTC3788-1
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_A = 25°C, VBIAS = 12V, unless otherwise noted (Note 2).
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
INTV_CC Linear Regulator
V_INTVCCVIN
Internal V_CC Voltage
V_LDOVIN
INTV_CC Load Regulation
V_INTVCCEXT
Internal V_CC Voltage
V_LDOEXT
INTV_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
6V < VBIAS < 38V, V_EXTVCC = 0V
I_CC = 0mA to 50mA, V_EXTVCC = 0V
V_EXTVCC = 6V
I_CC = 0mA to 40mA, V_EXTVCC = 6V
EXTV_CC Ramping Positive
5.2
5.4
5.6
V
0.5
2
%
5.2
5.4
5.6
V
0.5
2
%
4.5
4.8
5
V
250
mV
f_PROG
Programmable Frequency
f_LOW
Lowest Fixed Frequency
f_HIGH
Highest Fixed Frequency
f_SYNC
Synchronizable Frequency
PGOOD1 and PGOOD2 Outputs
R_FREQ = 25k
R_FREQ = 60k
R_FREQ = 100k
V_FREQ = 0V
V_FREQ = INTV_CC
PLLIN/MODE = External Clock
105
kHz
335
400
465
kHz
760
kHz
320
350
380
kHz
485
535
585
kHz
l 75
850
kHz
V_PGL
I_PGOOD
V_PG
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
I_PGOOD = 2mA
0.2
0.4
V
V_PGOOD = 5V
±1
μA
V_FB with Respect to Set Regulated Voltage
V_FB Ramping Negative
–12
–10
–8
%
Hysteresis
2.5
%
V_FB Ramping Positive
Hysteresis
8
10
12
%
2.5
%
t_PGOOD(DELAY) PGOOD Delay
BOOST1 and BOOST2 Charge Pump
PGOOD Going High to Low
25
μs
I_BOOST1,2
BOOST Charge Pump Available
Output Current
V_SW1,2 = 12V; V_BOOST1,2 – V_SW1,2 = 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-1 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-1 is guaranteed 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 formula: T_J = T_A + (P_D • 90°C/W)
Note 4: The LTC3788-1 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.
37881f
4