LT1766 Linear Technology, LT1766 Datasheet - Page 5

• Manufacturer Part Number: LT1766
• Description: 5.5V to 60V 1.5A/ 200kHz Step-Down Switching Regulator
• Manufacturer: Linear Technology

PI FU CTIO S
TYPICAL PERFOR A CE CHARACTERISTICS
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 flow 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
230
220
210
200
190
180
170
0.9
2.1
1.9
1.7
1.5
1.3
1.1
0.7
U
–50
–50
Switching Frequency
V
C
Pin Shutdown Threshold
–25
–25
U
JUNCTION TEMPERATURE ( C)
JUNCTION TEMPERATURE ( C)
0
0
25
25
U
50
50
75
75
W
100
100
1766 G13
1766 G10
U
125
125
450
400
350
300
250
200
150
100
7.5
7.0
6.5
6.0
5.5
5.0
50
0
0
Minimum Input Voltage with 5V
Output
0
Switch Voltage Drop
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
SWITCH CURRENT (A)
LOAD CURRENT (A)
0.5
MINIMUM INPUT
VOLTAGE TO START
MINIMUM INPUT
VOLTAGE TO RUN
T
J
= 25 C
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.
T
T
1
J
J
= –40 C
= 125 C
T
A
= 25 C
1766 G14
1766 G11
1.5
600
500
400
300
200
100
45
40
35
30
25
20
15
10
0
5
0
–50
0
BOOST Pin Current
Switch Minimum ON Time
vs Temperature
T
LT1766/LT1766-5
A
= 25 C
–25
JUNCTION TEMPERATURE ( C)
SWITCH CURRENT (A)
0
0.5
25
50
1
75
100
1766 G15
1766 G12
1766fa
5
125
1.5