Datasheet

LTC1871-1
3
18711fb
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
IN
= 5V, V
RUN
= 1.5V, R
FREQ
= 80k, V
MODE/SYNC
= 0V, unless otherwise specifi ed.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
RUN
+
Rising RUN Input Threshold Voltage 1.348 V
V
RUN
–
Falling RUN Input Threshold Voltage
●
1.223
1.198
1.248 1.273
1.298
V
V
V
RUN(HYST)
RUN Pin Input Threshold Hysteresis 50 100 150 mV
I-Grade (Note 2)
●
35 100 175 mV
I
RUN
RUN Input Current 160 nA
V
FB
Feedback Voltage V
ITH
= 0.4V (Note 5)
●
1.218
1.212
1.230 1.242
1.248
V
V
V
ITH
= 0.4V (Note 5), I-Grade (Note 2)
●
1.205 1.255 V
I
FB
FB Pin Input Current V
ITH
= 0.4V (Note 5) 18 60 nA
ΔV
FB
ΔV
IN
Line Regulation 2.5V ≤ V
IN
≤ 30V 0.002 0.02 %/V
2.5V ≤ V
IN
≤ 30V, I-Grade (Note 2)
●
0.002 0.03 %/V
ΔV
FB
ΔV
ITH
Load Regulation V
MODE/SYNC
= 0V, V
ITH
= 0.5V to 0.9V (Note 5)
●
–1 –0.1 %
V
MODE/SYNC
= 0V, V
ITH
= 0.5V to 0.9V (Note 5)
I-Grade (Note 2)
●
–1 –0.1 %
ΔV
FB(OV)
ΔFB Pin, Overvoltage Lockout V
FB(OV)
– V
FB(NOM)
in Percent 2.5 6 10 %
g
m
Error Amplifi er Transconductance I
TH
Pin Load = ±5µA (Note 5) 650 µmho
V
ITH(BURST)
Burst Mode Operation I
TH
Pin Voltage Falling I
TH
Voltage (Note 5) 195 mV
V
SENSE(MAX)
Maximum Current Sense Input Threshold Duty Cycle < 20% 120 150 180 mV
Duty Cycle < 20%, I-Grade (Note 2)
●
100 200 mV
I
SENSE(ON)
SENSE Pin Current (GATE High) V
SENSE
= 0V 35 50 µA
I
SENSE(OFF)
SENSE Pin Current (GATE Low) V
SENSE
= 30V 0.1 5 µA
Oscillator
f
OSC
Oscillator Frequency R
FREQ
= 80k 250 300 350 kHz
R
FREQ
= 80k, I-Grade (Note 2)
●
250 300 350 kHz
Oscillator Frequency Range 50 1000 kHz
I-Grade (Note 2)
●
50 1000 kHz
D
MAX
Maximum Duty Cycle 87 92 97 %
I-Grade (Note 2)
●
87 92 97 %
f
SYNC/
f
OSC
Recommended Maximum Synchronized
Frequency Ratio
f
OSC
= 300kHz (Note 6) 1.25 1.30
f
OSC
= 300kHz (Note 6), I-Grade (Note 2)
●
1.25 1.30
t
SYNC(MIN)
MODE/SYNC Minimum Input Pulse Width V
SYNC
= 0V to 5V 25 ns
t
SYNC(MAX)
MODE/SYNC Maximum Input Pulse Width V
SYNC
= 0V to 5V 0.8/f
OSC
ns
V
IL(MODE)
Low Level MODE/SYNC Input Voltage 0.3 V
I-Grade (Note 2)
●
0.3 V
V
IH(MODE)
High Level MODE/SYNC Input Voltage 1.2 V
I-Grade (Note 2)
●
1.2 V
R
MODE/SYNC
MODE/SYNC Input Pull-Down Resistance 50 k
V
FREQ
Nominal FREQ Pin Voltage 0.62 V