LTC3836_15 Datasheet, PDF (3/30 Pages) Linear Technology – Dual 2-Phase, No RSENSETM Low VIN Synchronous Controller

LTC3836
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = 3.3V unless otherwise specified.
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Undervoltage Lockout Threshold
Shutdown Threshold at RUN/SS
V_IN Falling
V_IN Rising
l 1.95 2.25 2.55
V
l 2.15 2.45 2.75
V
0.45 0.65 0.85
V
Start-Up Current Source
RUN/SS = 0V
0.4
0.65
1
μA
Regulated Feedback Voltage
–40°C to 85°C (Note 5)
l 0.591 0.6 0.609
V
Output Voltage Line Regulation
Output Voltage Load Regulation
V_FB1,2 Input Current
TRACK/SS2 Input Current
2.75V < V_IN < 4.5V (Note 5)
I_TH = 0.9V (Note 5)
I_TH = 1.7V
(Note 5)
TRACK/SS2 = 0V
0.05
0.2
mV/V
0.12
0.5
%
–0.12 –0.5
%
10
50
nA
1
1.5
2.2
μA
Overvoltage Protect Threshold
Overvoltage Protect Hysteresis
Measured at V_FB
0.66 0.68
0.7
V
20
mV
Auxiliary Feedback Threshold
SYNC/FCB Ramping Positive
0.525 0.6 0.675
V
Top Gate (TG) Drive 1, 2 Rise Time
C_L = 3000pF
Top Gate (TG) Drive 1, 2 Fall Time
C_L = 3000pF
Bottom Gate (BG) Drive 1, 2 Rise Time
C_L = 3000pF
Bottom Gate (BG) Drive 1, 2 Fall Time
C_L = 3000pF
Maximum Current
(SENSE⁺ – SW)
Sense
Voltage
(∆V_SENSE(MAX))
IPRG = Floating
IPRG = 0V
IPRG = V_IN
Maximum Duty Cycle
In Dropout
40
ns
40
ns
50
ns
40
ns
l 110
122
135
mV
l 70
82
95
mV
l 185
202
220
mV
97
%
Soft-Start Time
Oscillator and Phase-Locked Loop
Time for V_FB1 to Ramp from 0.05V to 0.55V
0.6
0.8
1
ms
Oscillator Frequency
Phase-Locked Loop Lock Range
Unsynchronized (SYNC/FCB Not Clocked)
PLLLPF = Floating
PLLLPF = 0V
PLLLPF = V_IN
SYNC/FCB Clocked
Minimum Synchronizable Frequency
Maximum Synchronizable Frequency
480
550
600
kHz
260
300
340
kHz
650
750
825
kHz
l
200
250
kHz
l 850 1150
kHz
Phase Detector Output Current
Sinking
Sourcing
PGOOD Output
f_OSC > f_SYNC/FCB
f_OSC > f_SYNC/FCB
–4
μA
4
μA
PGOOD Voltage Low
PGOOD Trip Level
I_PGOOD Sinking 1mA
V_FB with Respect to Set Output Voltage
V_FB < 0.6V, Ramping Positive
V_FB < 0.6V, Ramping Negative
V_FB > 0.6V, Ramping Negative
V_FB > 0.6V, Ramping Positive
140
mV
–13 –10.0 –7
%
–16 –13.3 –10
%
7
10.0
13
%
10
13.3
16
%
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 LTC3836 is guaranteed to meet specified performance from
0°C to 85°C. Specifications over the –40°C to 85°C operating range are
assured by design, characterization and correlation with statistical process
controls.
Note 3: T_J is calculated from the ambient temperature T_A and power dissi-
pation P_D according to the following formula: T_J = T_A + (P_D • θ_JA°C/W)
Note 4: Dynamic supply current is higher due to gate charge being
delivered at the switching frequency.
Note 5: The LTC3836 is tested in a feedback loop that servos I_TH to a
specified voltage and measures the resultant V_FB voltage.
Note 6: Peak current sense voltage is reduced dependent on duty cycle to
a percentage of value as shown in Figure 1.
3836fb
3