Datasheet
LT3689/LT3689-5
3
3689fe
For more information www.linear.com/LT3689
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Fixed Undervoltage Lockout
l
3.4 3.7 V
V
IN
Overvoltage Lockout
l
36 38 40 V
Quiescent Current from V
IN
V
EN/UVLO
= 0.3V
V
OUT
= 3V, Not Switching
V
OUT
= 0V, Not Switching
l
0.01
50
125
0.5
95
175
µA
µA
µA
Quiescent Current from OUT V
EN/UVLO
= 0.3V
V
OUT
= 3V, Not Switching (Note 7)
V
OUT
= 0V, Not Switching
l
0.01
75
–5
0.5
150
–20
µA
µA
µA
LT3689-5 Quiescent Current from V
IN
V
EN/UVLO
= 0.3V
V
OUT
= 5.5V (Note 8)
V
OUT
= 0V
l
0.01
50
125
0.5
95
175
µA
µA
µA
LT3689-5 Quiescent Current from OUT V
EN/UVLO
= 0.3V
V
OUT
= 5.5V
l
8
95
16
150
µA
µA
LT3689 FB Voltage
l
0.790
0.780
0.800 0.812
0.812
V
V
LT3689-5 Output Voltage
l
4.950
4.900
5.000 5.050
5.100
V
V
LT3689 FB Pin Bias Current V
FB
= 0.800V
l
–30 –100 nA
LT3689 FB Voltage Line Regulation 5V < V
IN
< 36V 0.005 %/V
LT3689-5 Output Voltage Line Regulation 5.5V < V
IN
< 36V 0.005 %/V
f
SW
Switching Frequency R
T
= 4.02k
R
T
= 31.62k
l
l
1.8
420
2
500
2.2
540
MHz
kHz
t
SW(OFF)
Switch Off-Time 120 160 ns
Foldback Frequency R
T
= 4.02k, V
FB
= 0V 250 kHz
Switch Current Limit (Note 4)
l
1.15 1.55 1.95 A
Switch V
CESAT
I
SW
= 0.8A 450 mV
Switch Leakage Current 0.01 1 µA
DA Current Limit 0.85 1.2 1.5 A
Boost Schottky Reverse Leakage V
BST
= 12V, V
OUT
= 0V 0.1 5 µA
Minimum BST Above SW Voltage 1.8 2.5 V
BST Pin Current I
SW
= 0.8A 15 25 mA
EN/UVLO Threshold Voltage 1.150 1.260 1.350 V
EN/UVLO Pin Current V
EN/UVLO
= 1.35V
V
EN/UVLO
= 1.15V
2.5
0. 01
4.1
1
5.5
µA
µA
EN/UVLO Pin Current Hysteresis I(V
EN/UVLO
= 1.15V) – I(V
EN/UVLO
= 1.35V) 2.8 3.8 4.8 µA
SYNC Threshold Voltage 0.4 0.8 1 V
V
RST
Reset Threshold as % of V
FB
l
88 90 92 %
t
RST
Reset Timeout Period C
POR
= 8200pF
l
17 19 21 ms
t
WDU
Watchdog Upper Boundary C
WDT
= 1000pF
l
17 19 21 ms
t
WDL
Watchdog Lower Boundary C
WDT
= 1000pF
l
610 675 785 µs
V
OL
RST, WDO Output Voltage Low I
SINK
= 2.5mA
I
SINK
= 100µA
l
l
0.15
0.05
0.4
0.3
V
V
V
OH
RST, WDO Output Voltage High (Note 6)
l
V
OUT
–1 V
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
OUT
= 5V, unless otherwise noted. (Note 3)