Datasheet
LTM4608A
12
4608afd
Forced Continuous Operation
In applications where fixed frequency operation is more
critical than low current efficiency, and where the lowest
output ripple is desired, forced continuous operation should
be used. Forced continuous operation can be enabled by
tying the MODE pin to GND. In this mode, inductor cur-
rent is allowed to reverse during low output loads, the I
TH
voltage is in control of the current comparator threshold
Table 3. Output Voltage Response Versus Component Matrix (Refer to Figure 18) 0A to 3A Load Step
TYPICAL MEASURED VALUES
C
OUT1
VENDORS VALUE PART NUMBER C
OUT2
VENDORS VALUE PART NUMBER
TDK 22µF, 6.3V C3216X7S0J226M Sanyo POSCAP 150µF, 10V 10TPD150M
Murata 22µF, 16V GRM31CR61C226KE15L C
IN
(BULK) VENDORS VALUE PART NUMBER
TDK 100µF, 6.3V C4532X5R0J107MZ Sanyo 100µF, 10V 10CE100FH
Murata 100µF, 6.3V GRM32ER60J107M
V
OUT
(V)
C
IN
(CERAMIC)
C
IN
(BULK)*
C
OUT1
(CERAMIC)
C
OUT2
(BULK)
I
TH
C1
C3
V
IN
(V)
DROOP
(mV)
PEAK-TO- PEAK
DEVIATION (mV)
RECOVERY
TIME (µs)
LOAD STEP
(A/µs)
R
FB
(kΩ)
1.0 10µF 100µF 100µF × 2 None 68pF None 5 13 26 7 3 14.7
1.0 10µF 100µF 22µF × 1 150µF × 2 None None 100pF 5 17 34 8 3 14.7
1.0 10µF 100µF 100µF × 2 None 68pF None 3.3 13 26 7 3 14.7
1.0 10µF 100µF 22µF × 1 150µF × 2 None None 100pF 3.3 17 34 10 3 14.7
1.0 10µF 100µF 100µF × 2 None 68pF None 2.7 13 26 7 3 14.7
1.0 10µF 100µF 22µF × 1 150µF × 2 None None 100pF 2.7 17 34 8 3 14.7
1.2 10µF 100µF 100µF × 2 None 100pF None 5 16 32 8 3 10
1.2 10µF 100µF 22µF × 1 150µF × 2 None None 100pF 5 20 41 10 3 10
1.2 10µF 100µF 100µF × 2 None 100pF None 3.3 16 32 8 3 10
1.2 10µF 100µF 22µF × 1 150µF × 2 None None 100pF 3.3 20 41 10 3 10
1.2 10µF 100µF 100µF × 2 None 100pF None 2.7 16 32 10 3 10
1.2 10µF 100µF 22µF × 1 150µF × 2 None 47pF None 2.7 16 32 8 3 10
1.5 10µF 100µF 100µF × 2 None 100pF None 5 18 36 8 3 6.65
1.5 10µF 100µF 22µF × 1 150µF × 2 None None 47pF 5 20 41 12 3 6.65
1.5 10µF 100µF 100µF × 2 None 100pF None 3.3 16 32 10 3 6.65
1.5 10µF 100µF 22µF × 1 150µF × 2 None None 47pF 3.3 20 41 12 3 6.65
1.5 10µF 100µF 100µF × 2 None 100pF None 2.7 18 36 10 3 6.65
1.5 10µF 100µF 22µF × 1 150µF × 2 None None None 2.7 20 41 12 3 6.65
1.8 10µF 100µF 100µF × 1 None 47pF None 5 22 42 8 3 4.87
1.8 10µF 100µF 22µF × 1 150µF × 2 None None 47pF 5 21 42 12 3 4.87
1.8 10µF 100µF 100µF × 2 None 120pF None 3.3 21 43 12 3 4.87
1.8 10µF 100µF 22µF × 1 150µF × 2 None None 47pF 3.3 21 41 12 3 4.87
1.8 10µF 100µF 100µF × 2 None 120pF None 2.7 22 44 12 3 4.87
1.8 10µF 100µF 22µF × 1 150µF × 2 None None None 2.7 21 42 14 3 4.87
2.5 10µF 100µF 100µF × 1 None 100pF None 5 28 42 10 3 3.09
2.5 10µF 100µF 22µF × 1 150µF × 1 None 22pF None 5 33 60 10 3 3.09
2.5 10µF 100µF 100µF × 1 None 100pF None 3.3 30 60 10 3 3.09
2.5 10µF 100µF 22µF × 1 150µF × 1 None 22pF None 3.3 21 41 10 3 3.09
3.3 10µF 100µF 100µF × 1 100pF 22pF None 5 38 74 10 3 2.21
3.3 10µF 100µF 22µF × 1 150µF × 1 None None None 5 39 75 12 3 2.21
*Bulk capacitance is optional if V
IN
has very low input impedance.
applicaTions inForMaTion
throughout, and the top MOSFET always turns on with each
oscillator pulse. During start-up, forced continuous mode
is disabled and inductor current is prevented from revers-
ing until the LTM4608A’s output voltage is in regulation.
Multiphase Operation
For output loads that demand more than 8A of current,
multiple LTM4608As can be cascaded to run out of phase to