LTC3731H_15 Datasheet, PDF (4/34 Pages) Linear Technology – 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller

LTC3731H
Electrical Characteristics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_CC = V_RUN/SS = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
Power Good Output Indication
V_PGL
PGOOD Voltage Output Low
I_PGOOD
PGOOD Output Leakage
V_PGTHNEG
V_PGTHPOS
PGOOD Trip Thresholds
V_EAIN Ramping Negative
V_EAIN Ramping Positive
V_PGDLY
Power Good Fault Report Delay
Oscillator and Phase-Locked Loop
I_PGOOD = 2mA, G Package
I_PGOOD = 1.6mA, UH Package
V_PGOOD = 5V
V_EAIN with Respect to Set Output Voltage, PGOOD
Goes Low After V_UVDLY Delay
After V_EAIN is Forced Outside the PGOOD Thresholds
0.1
0.3
V
0.5
1
V
1
µA
–7
–10
–13
%
7
10
13
%
100
150
µs
f_NOM
f_LOW
f_HIGH
V_PLLTH
R_PLLIN
I_PLLFLTR
R_RELPHS
CLKOUT
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Threshold
PLLIN Input Resistance
Phase Detector Output Current
Sinking Capability
Sourcing Capability
Controller 2-Controller 1 Phase
Controller 3-Controller 1 Phase
Controller 1 TG to CLKOUT Phase
V_PLLFLTR = 1.2V
V_PLLFLTR = 0V
V_PLLFLTR = 2.4V
Minimum Pulse Width > 100ns
f_PLLIN < f_OSC
f_PLLIN > f_OSC
PHASMD = 0V
PHASMD = 5V
360
400
440
kHz
190
225
260
kHz
600
680
750
kHz
1
V
50
kΩ
20
µA
20
µA
120
Deg
240
Deg
30
Deg
60
Deg
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 LTC3731H is guaranteed to meet specifications over the –40°C
to 140°C operating junction temperature range. Note that the maximum
ambient temperature is determined by specific operating conditions in
conjunction with board layout, the rated package thermal resistance and
other environmental factors.
Junction temperature (T_J) is calculated from the ambient temperature T_A
and power dissipation PD according to the following formula:
LTC3731HG: T_J = T_A + (P_D • 70°C/W)
LTC3731HG: T_J = T_CASE + (P_D • 25°C/W)
LTC3731HUH: T_J = T_A + (P_D • 34°C/W)
High junction temperatures degrade operating lifetimes. Operating lifetime
at junction temperatures greater than 125°C is derated to 1000 hours. The
LTC3731H is tested under pulsed load conditions such that T_J ≈ T_A.
Note 3: The IC is tested in a feedback loop that servoes the error amplifier
output voltage to its midrange point (V_ITH = 1.2V).
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 5: The minimum on-time condition corresponds to an inductor
peak-to-peak ripple current of ≥40% of I_MAX (see minimum on-time
considerations in the Applications Information Section).
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions.
Overtemperature protection becomes active at a junction temperature
greater than the maximum operating temperature. Continuous operation
above the specified maximum operating junction temperature may impair
device reliability.
3731Hfb