LTC3769_15 Datasheet, PDF (4/32 Pages) Linear Technology – 60V Low IQ Synchronous Boost Controller

LTC3769
Electrical Characteristics The l denotes the specifications which apply over the specified 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
Internal V_CC Voltage
INTV_CC Load Regulation
Internal V_CC Voltage
INTV_CC Load Regulation
EXTV_CC Switchover Voltage
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
6V < V_BIAS < 60V, V_EXTVCC = 0
5.2
5.4
5.6
V
I_CC = 0mA to 50mA
6V < V_EXTVCC < 13V
0.5
2
%
5.2
5.4
5.6
V
I_CC = 0mA to 40mA, V_EXTVCC = 8.5V
0.5
2
%
EXTV_CC Ramping Positive
l 4.5
4.8
5
V
250
mV
Programmable Frequency
f_LOW
Lowest Fixed Frequency
R_FREQ = 25k
R_FREQ = 60k
R_FREQ = 100k
V_FREQ = 0V
105
kHz
335
400
465
kHz
760
kHz
320
350
380
kHz
Highest Fixed Frequency
Synchronizable Frequency
V_FREQ = INTV_CC
PLLIN/MODE = External Clock
488
535
585
kHz
l 75
850
kHz
PGOOD Output
PGOOD Voltage Low
I_PGOOD = 2mA
0.2
0.4
V
PGOOD Leakage Current
V_PGOOD = 5V
±1
µA
PGOOD Trip Level
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
%
PGOOD Delay
PGOOD Going High to Low
45
µs
OV Protection Threshold
BOOST Charge Pump
V_FB Ramping Positive, OVMODE = 0V
1.296 1.32 1.344
V
BOOST Charge Pump Available Output
Current
V_SW = 12V; V_BOOST – V_SW = 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 LTC3769 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3769E 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
LTC3769I is guaranteed over the –40°C to 125°C operating junction
temperature range, the LTC3769H is guaranteed over the –40°C to 150°C
operating temperature range and the LTC3769MP is tested and guaranteed
over the full –55°C to 150°C operating junction temperature range. High
junction temperatures degrade operating lifetimes; operating lifetime
is derated for junction temperatures greater than 125°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 = 47°C/W for the QFN package
and θ_JA = 38°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 LTC3769 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.
3769f
4
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