LTC3731 Datasheet, PDF (4/32 Pages) Linear Technology – 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller

LTC3731
ELECTRICAL CHARACTERISTICS The ● 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
I_PGOOD
PGOOD/PHASMD Bias I
V_PGTHNEG
V_PGTHPOS
PGOOD Trip Thesholds
V_DIFFOUT Ramping Negative
V_DIFFOUT 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, G Package
0 ≤ V_PHASMD/PG ≤ V_CC, UH Package
V_DIFFOUT with Respect to Set Output Voltage,
HGOOD Goes Low After V_UVDLY Delay
After V_EAIN is Forced Outside the PGOOD Thresholds
0.1
0.3
V
0.5
1.0
V
1
µA
–10
±3
10
µA
–7
–10
–13
%
7
10
13
%
100
150
µs
f_NOM
f_LOW
f_HIGH
V_PLLTH
R_PLLIN
I_PLLFLTR
R_RELPHS
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
V_PLLFLTR = 1.2V
V_PLLFLTR = 0V
V_PLLFLTR = 2.4V
Minimum Pulse Width > 100ns
f_PLLIN < f_OSC
f_PLLIN > f_OSC
360 400
440
kHz
190 225
260
kHz
600 680
750
kHz
1
V
50
kΩ
20
µA
20
µA
120
Deg
240
Deg
CLKOUT
Controller 1 TG to CLKOUT Phase
PHASMD = 0V
PHASMD = 5V
30
Deg
60
Deg
Differential Amplifier
A_V
Differential Gain
V_OS
Input Offset Voltage Magnitude
IN⁺ = IN^– = 1.2V, I_OUT = 1mA,
Input Referred; Gain = 1
0.995 1.000 1.005 V/V
0.5
5
mV
CM
CMRR
I_CL
GBP
SR
V_O(MAX)
R_IN
Common Mode Input Voltage Range
Common Mode Rejection Ratio
Output Current Sourcing
Gain Bandwidth Product
Slew Rate
Maximum High Output Voltage
Input Resistance
0V < IN⁺ = IN^– < 5V, I_OUT = 1mA, Input Referred
I_OUT = 1mA
R_L = 2k
I_OUT = 1mA
Measured at IN⁺ Pin
0
V_CC
V
50
70
dB
10
40
mA
2
MHz
5
V/µs
V_CC – 1.2 V_CC – 0.8
V
80
kΩ
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: T_J is calculated from the ambient temperature T_A and power
dissipation P_D according to the following formula:
LTC3731CG/LTC3731IG: T_J = T_A + (P_D × 95°C/W)
LTC3731CG/LTC3731IG: T_J = T_CASE + (P_D × 32°C/W)
LTC3731CUH/LTC3731IUH: T_J = T_A + (P_D × 34°C/W)
Note 3: The IC is tested in a feedback loop that includes the differential
amplifier loaded with 100µA to ground driving the error amplifier and
servoing the resultant voltage to the midrange point for the error amplifier
(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. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
3731fa
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