Datasheet

LTC3708
3
3708fb
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
CC
= 5V, DRV
CC
= 5V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ΔV
FB(LOADREG)1,2
Feedback Voltage Load Regulation I
TH
= 0.5V to 1.9V (Note 3) –0.05 –0.2 %
g
m(EA)1,2
Error Amplifi er Transconductance I
TH
= 1.2V (Note 3)
l
1.2 1.45 1.7 mS
t
ON1,2
On-Time I
ON
= 60μA, V
FCB
= 0V
I
ON
= 30μA, V
FCB
= 0V
94
186
116
233
138
280
ns
ns
t
ON(MIN)1,2
Minimum On-Time I
ON
= 180μA 50 85 ns
t
OFF(MIN)1,2
Minimum Off-Time I
ON
= 30μA 270 350 ns
V
SENSE(MAX)1,2
Maximum Current Sense Threshold V
RNG
= 1V, V
FB
= 0.565V
V
RNG
= 0V, V
FB
= 0.565V
V
RNG
= VCC, V
FB
= 0.565V
125
90
180
143
100
200
160
110
220
mV
mV
mV
V
SENSE(MIN)1,2
Minimum Current Sense Threshold V
RNG
= 1V, V
FB
= 0.635V
V
RNG
= 0V, V
FB
= 0.635V
V
RNG
= V
CC
, V
FB
= 0.635V
–62
–42
–88
mV
mV
mV
ΔV
FB(OV)1,2
Overvoltage Fault Threshold 8.5 10 11.5 %
ΔV
FB(UV)1,2
Undervoltage Fault Threshold –380 –420 –460 mV
V
RUN/SS(ON)
RUN Pin Start Threshold
l
0.8 1.3 1.8 V
V
RUN/SS(LE)
RUN Pin Latchoff Enable Threshold RUN/SS Pin Rising 2.6 3 3.3 V
V
RUN/SS(LT)
RUN Pin Latchoff Threshold RUN/SS Pin Falling 2.2 2.5 2.8 V
I
RUN/SS(C)
Soft-Start Charge Current V
RUN/SS
= 0V –0.5 –1.2 –2 μA
I
RUN/SS(D)
Soft-Start Discharge Current V
RUN/SS
= V
RUN/SS(LE)
, V
FB1,2
= 0V 0.8 2 3 μA
V
CC(UVLO)
Undervoltage Lockout V
CC
Falling 3.2 3.6 V
V
CC(UVLOR)
Undervoltage Lockout Release V
CC
Rising 3.5 3.8 V
TG R
UP1,2
TG Driver Pull-Up On-Resistance TG High (Note 6) 2 Ω
TG R
DOWN1,2
TG Driver Pull-Down On-Resistance TG Low (Note 6) 2 Ω
BG R
UP1,2
BG Driver Pull-Up On-Resistance BG High (Note 6) 3 Ω
BG R
DOWN1,2
BG Driver Pull-Down On-Resistance BG Low (Note 6) 1 Ω
Tracking
I
TRACK1,2
TRACK Pin Input Current I
TH
= 1.2V, V
TRACK
= 0.2V (Note 3) –100 –150 nA
V
FB(TRACK1,2)
Feedback Voltage at Tracking V
TRACK
= 0V, I
TH
= 1.2V (Note 3)
V
TRACK
= 0.2V, I
TH
= 1.2V (Note 3)
V
TRACK
= 0.4V, I
TH
= 1.2V (Note 3)
–10
190
390
0
200
400
–10
210
410
mV
mV
mV
PGOOD Output
ΔV
FBH1,2
PGOOD Upper Threshold Either V
FB
Rising 8.5 10 11.5 %
ΔV
FBL1,2
PGOOD Lower Threshold Either V
FB
Falling –8.5 –10 –11.5 %
ΔV
FB(HYS)1,2
PGOOD Hysteresis V
FB
Returning 3 5 %
V
PGL
PGOOD Low Voltage I
PGOOD
= 5mA 0.1 0.4 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 7V ±1 μA
PG Delay PGOOD Delay V
FB
Falling 100 μs
Phase-Locked Loops
V
FCB(DC)
Forced Continuous Threshold Measured with a DC Voltage at FCB Pin 1.9 2.1 2.3 V
V
FCB(AC)
Clock Input Threshold Measured with a AC Pulse at FCB Pin 1 1.5 2 V
I
EXTLPF
External Phase Detector Output Current
Sourcing Capability
Sinking Capability
f
FCB
< f
SW1
, V
EXTLPF
= 0V
f
FCB
> f
SW1
, V
EXTLPF
= 2.4
20
–20
μA
μA