Datasheet
LT1766/LT1766-5
7
1766fc
PIN FUNCTIONS
TYPICAL PERFORMANCE CHARACTERISTICS
Switching Frequency BOOST Pin Current
Minimum Input Voltage with 5V
Output
Switch Voltage Drop
JUNCTION TEMPERATURE (°C)
–50
FREQUENCY (kHz)
50 100
1766 G10
0
25 75
230
220
210
200
190
180
170
–25 150125
LOAD CURRENT (A)
0
INPUT VOLTAGE (V)
1766 G11
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
7.5
7.0
6.5
6.0
5.5
5.0
MINIMUM INPUT
VOLTAGE TO START
MINIMUM INPUT
VOLTAGE TO RUN
T
A
= 25°C
SWITCH CURRENT (A)
0 0.5 1 1.5
BOOST PIN CURRENT (mA)
1766 G12
45
40
35
30
25
20
15
10
5
0
T
A
= 25°C
JUNCTION TEMPERATURE (°C)
–50
1.5
1.7
2.1
25 75
1766 G13
1.3
1.1
–25 0
50 100 150125
0.9
0.7
1.9
THRESHOLD VOLTAGE (V)
SWITCH CURRENT (A)
0 0.5 1 1.5
SWITCH VOLTAGE (mV)
1766 G14
450
400
350
300
250
200
150
100
50
0
T
J
= 125°C
T
J
= 150°C
T
J
= 25°C
T
J
= –40°C
JUNCTION TEMPERATURE (°C)
–50
SWITCH MINIMUM ON TIME (ns)
400
500
600
25 75
1766 G15
300
200
–25 0
50 100 150125
100
0
V
C
Pin Shutdown Threshold
Switch Minimum On-Time
vs Temperature
GND (Pins 1, 8, 9, 16, 17): The GND pin connections act
as the reference for the regulated output, so load regula-
tion will suffer if the ground end of the load is not at the
same voltage as the GND pins of the IC. This condition will
occur when load current or other currents fl ow through
metal paths between the GND pins and the load ground.
Keep the paths between the GND pins and the load ground
short and use a ground plane when possible. The GND
pin also acts as a heat sink and should be soldered to a
large copper plane to reduce thermal resistance. For the
FE package, the exposed pad should be soldered to the
copper ground plane underneath the device. (See Applica-
tions Information—Layout Considerations.)
SW (Pin 2): The switch pin is the emitter of the on-chip
power NPN switch. This pin is driven up to the input pin
voltage during switch on-time. Inductor current drives the
switch pin negative during switch off-time. Negative volt-
age is clamped with the external catch diode. Maximum
negative switch voltage allowed is –0.8V.
NC (Pins 3, 5, 7, 13): No Connection.