LTC3899_15 Datasheet, PDF (4/38 Pages) Linear Technology – 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

LTC3899
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_BIAS = 12V, V_RUN1,2,3 = 5V, V_EXTVCC = 0V, V_DRVSET =
0V, VPRG3 = Float unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
I_Q
Input DC Supply Current
(Note 5), V_DRVSET = 0V
Pulse-Skipping or Forced Continuous Mode RUN1 = 5V and RUN2,3 = 0V or
1.6
(One Channel On)
RUN2 = 5V and RUN1,3 = 0V or
1.6
RUN3 = 5V and RUN1,2 = 0V,
0.8
V_FB1,2 = 0.83V (No Load), V_FB3 = 1.25V
Pulse-Skipping or Forced Continuous Mode RUN1,2,3 = 5V, V_FB1,2 = 0.83V (No Load),
3
(All Channels On)
V_FB3 = 1.25V
Sleep Mode (One Channel On, Buck)
RUN1 = 5V and RUN2,3 = 0V or
RUN2 = 5V and RUN1,3 = 0V
V_FB1,2 = 0.83V (No Load)
l
29
55
Sleep Mode (One Channel On, Boost)
RUN3 = 5V and RUN1,2 = 0V, V_FB3 = 1.25V
29
50
Sleep Mode (Buck and Boost Channel On)
RUN1 = 5V and RUN2 = 0V or
RUN2 = 5V and RUN1 = 0V, RUN3 = 5V,
V_FB1,2 = 0.83V (No Load), V_FB3 = 1.25V
34
55
Sleep Mode (All Three Channels On)
RUN1,2,3 = 5V, V_FB1,2 = 0.83V (No Load),
V_FB3 = 1.25V
39
60
Shutdown
RUN1,2,3 = 0V
3.6
10
UVLO
Undervoltage Lockout
V_OVL1,2
I_SENSE1,2+
I_SENSE3+
I_SENSE1,2–
Buck Feedback Overvoltage Protection
SENSE⁺ Pin Current
SENSE⁺ Pin Current
SENSE^– Pins Current
I_SENSE3–
DF_MAX(TG)
SENSE^– Pin Current
Maximum Duty Factor for TG
DRV_CC Ramping Up
DRVSET = 0V or R_DRVSET ≤ 100kΩ
l
DRVSET = INTV_CC
l
4.0 4.2
7.5 7.8
DRV_CC Ramping Down
DRVSET = 0V or R_DRVSET ≤ 100kΩ
DRVSET = INTV_CC
l 3.6 3.8 4.0
l 6.4 6.7 7.0
Measured at V_FB1,2 Relative to Regulated V_FB1,2
7
10
13
Bucks (Channels 1 and 2)
±1
Boost (Channel 3)
170
Bucks (Channels 1 and 2)
V_OUT1,2 < V_INTVCC – 0.5V
V_OUT1,2 > V_INTVCC + 0.5V
Boost (Channel 3) V_SENSE+, V_SENSE– = 12V
Bucks (Channels 1,2) in Dropout, FREQ = 0V
Boost (Channel 3) in Overvoltage
±1
700
±1
97.5 99
100
DF_MAX(BG)
Maximum Duty Factor for BG
Bucks (Channels 1,2) in Overvoltage
100
Boost (Channel 3)
96
I_TRACK/SS1,2 Soft-Start Charge Current
I_SS
Soft-Start Charge Current
V_RUN1,2,3 ON RUN Pin On Threshold
V_RUN1,2,3 Hyst RUN Pin Hysteresis
V_SENSE(MAX) Maximum Current Sense Threshold
V_SENSE(CM)
SENSE3 Pins Common Mode Range
(BOOST Converter Input Supply Voltage)
V_TRACK/SS1,2 = 0V
V_SS3 = 0V
V_RUN1, V_RUN2, V_RUN3 Rising
V_FB1,2 = 0.7V, V_SENSE1,2– = 3.3V,
V_FB3 = 1.1V, V_SENSE3+ = 12V
8
10
12
8
10
12
l 1.22 1.275 1.33
75
l 65
75
85
2.2
60
Gate Driver
TG1,2,3
Pull-Up On-Resistance
V_DRVSET = INTV_CC
2.2
Pull-Down On-Resistance
1.0
BG1,2,3
Pull-Up On-Resistance
V_DRVSET = INTV_CC
2.2
Pull-Down On-Resistance
1.0
UNITS
mA
mA
µA
µA
µA
µA
µA
V
V
V
V
%
µA
µA
µA
µA
µA
%
%
%
%
µA
µA
V
mV
mV
V
Ω
Ω
Ω
Ω
3899f
4
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