LTC3612_15 Datasheet, PDF (3/30 Pages) Linear Technology – 3A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter

LTC3612
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 = 3.3V, RT/SYNC = SV_IN, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
V_IN
Operating Voltage Range
l 2.25
5.5
V
V_UVLO
Undervoltage Lockout Threshold
SV_IN Ramping Down
SV_IN Ramping Up
l 1.7
l
V 
2.25
V
V_FB
Feedback Voltage Internal Reference (Notes 3, 4) V_TRACK/SS = SV_IN, V_DDR = 0V
0°C < T_J < 85°C
0.594
0.6
0.606
V
–40°C < T_J < 125°C
l 0.591
0.609
V
–55°C < T_J < 150°C
l 0.589
0.611
V
Feedback Voltage External Reference (Notes 3, 4) V_TRACK/SS = 0.3V, V_DDR = SV_IN
0.289
0.3
0.311
V
(Note 7)
(Notes 3, 4) V_TRACK/SS = 0.5V, V_DDR = SV_IN
0.489
0.5
0.511
V
I_FB
Feedback Input Current
V_FB = 0.6V
l
±30
nA
∆V_LINEREG
Line Regulation
SV_IN = PV_IN = 2.25V to 5.5V
l
(Notes 3, 4) TRACK/SS = SV_IN
0.2
%/V
∆V_LOADREG
Load Regulation
ITH from 0.5V to 0.9V (Notes 3, 4)
V_ITH = SV_IN (Note 5)
0.25
%
2.6
%
I_S
Active Mode
V_FB = 0.5V, V_MODE = SV_IN (Note 6)
1100
µA
Sleep Mode
V_FB = 0.7V, V_MODE = 0V, ITH = SV_IN
(Note 5)
70
100
µA
R_DS(ON)
I_LIM
Shutdown
Top Switch On-Resistance
Bottom Switch On-Resistance
Top Switch Current Limit
V_FB = 0.7V, V_MODE = 0V (Note 4)
SV_IN = PV_IN = 5.5V, V_RUN = 0V
PV_IN = 3.3V (Note 10)
PV_IN = 3.3V (Note 10)
Sourcing (Note 8), V_FB = 0.5V
Duty Cycle <35%
Duty Cycle = 100%
120
160
µA
0.1
1
µA
70
 
mΩ
45
mΩ
5.2
6
6.8
A
3.7
A
Bottom Switch Current Limit
Sinking (Note 8), V_FB = 0.7V,
Forced Continuous Mode
–3
–4
–5
A
g_m(EA)
I_EAO
t_SS
V_TRACK/SS
t_{TRACK/SS_DIS}
Error Amplifier Transconductance
Error Amplifier Max Output Current
Internal Soft-Start Time
Enable Internal Soft-Start
Soft-Start Discharge Time at
Start-Up
–5µA < I_ITH < 5µA (Note 4)
(Note 4)
V_FB from 0.06V to 0.54V,
TRACK/SS = SV_IN
(Note 7 )
200
µS
±30
µA
0.65
1
1.5
ms
0.62
V 
70
µs
R_{ON(TRACK/SS_DIS)} TRACK/SS Pull-Down Resistor at
Start-Up
200
Ω
f_OSC
f_SYNC
V_RT/SYNC
Oscillator Frequency
Internal Oscillator Frequency
Synchronization Frequency
SYNC Level High
SYNC Level Low
RT/SYNC = 370k
V_RT/SYNC = SV_IN
l 0.8
1
1.2
MHz
l 1.8
2.25
2.7
MHz
0.3
4
MHz
1.2
V
.
0.3
V
I_SW(LKG)
V_DDR
V_MODE
(Note 9)
Switch Leakage Current
DDR Option Enable Voltage
Internal Burst Mode Operation
Pulse-Skipping Mode
Forced Continuous Mode
External Burst Mode Operation
SV_IN = PV_IN = 5.5V, V_RUN = 0V
 
 
0.1
1
µA
SV_IN – 0.3
V
0.3
V
SV_IN – 0.3 
V
1.1
SV_IN • 0.58
V
0.45
 
0.8
V
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