LTC3875_15 Datasheet, PDF (4/44 Pages) Linear Technology – Dual, 2-Phase, Synchronous Controller with Low Value DCR Sensing and Temperature Compensation

LTC3875
Electrical Characteristics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T_A = 25°C (Note 2). V_IN = 15V, V_RUN1,2 = 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
TG/BG t_1D
Top Gate Off to Bottom Gate On
Delay Synchronous Switch-On
Delay Time
C_LOAD = 3300pF Each Driver
30
ns
BG/TG t_2D
Bottom Gate Off to Top Gate On
Delay Synchronous Switch-On
Delay Time
C_LOAD = 3300pF Each Driver
30
ns
t_ON(MIN)
Minimum On-Time
INTV_CC Linear Regulator
V_INTVCC
Internal V_CC Voltage
V_LDO INT
INTV_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDO EXT
EXTV_CC Voltage Drop
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
(Note 7)
6V < V_IN < 38V
I_CC = 0mA to 20mA
EXTV_CC Ramping Positive
I_CC = 20mA, V_EXTVCC = 5.5V
90
ns
5.3 5.5 5.7
V
0.5 2.0
%
l 4.5 4.7
V
50 100
mV
200
mV
f_NOM
f_LOW
f_HIGH
R_MODE/PLLIN
I_FREQ
CLKOUT
CLK High
CLK Low
Nominal Frequency
Lowest Frequency
Highest Frequency
MODE/PLLIN Input Resistance
Frequency Setting Current
Phase (Relative to Controller 1)
Clock Output High Voltage
Clock Output Low Voltage
V_FREQ = 1.2V
V_FREQ = 0V
V_FREQ ≥ 2.4V
PHASMD = GND
PHASMD = FLOAT
PHASMD = INTV_CC
V_INTVCC = 5.5V
450 500 550
kHz
220 250 270
kHz
650 720 790
kHz
250
kΩ
9.5 10 10.5
µA
60
Deg
90
Deg
120
Deg
4.5 5.5
V
0.2
V
V_PGL
I_PGOOD
V_PG
On-Chip Driver
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level, Either Controller
I_PGOOD = 2mA
V_PGOOD = 5.5V
V_{OVVSOONSSSNN+SS}w₊₊ iRRthaammReppsiinnpggecNPtoetogsiatStivieveteOutput Voltage
0.1 0.3
V
±2
µA
–7.5
%
7.5
%
TG R_UP
TG R_DOWN
BG R_UP
BG R_DOWN
TG Pull-Up R_DS(ON)
TG Pull-Down R_DS(ON)
BG Pull-Up R_DS(ON)
BG Pull-Down R_DS(ON)
TG High
TG Low
BG High
BG Low
2.6
Ω
1.5
Ω
2.4
Ω
1.1
Ω
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 LTC3875 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3875E 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
LTC3875I is guaranteed over the full –40° to 125° operating junction
temperature range. 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.
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 • 33°C/W)
Note 4: The LTC3875
specified voltage and
is tested in a feedback
measures the resultant
loop that servos
V_OSNS1,2+.
V_ITH1,2
to
a
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: The minimum on-time condition is specified for an inductor
peak-to-peak ripple current ≥40% of I_MAX (see Minimum On-Time
Considerations in the Applications Information section).
Note 8: Guaranteed by design.
3875fa
4
For more information www.linear.com/LTC3875