LT1307CS8 Linear Technology, LT1307CS8 Datasheet - Page 11

• Manufacturer Part Number: LT1307CS8
• Description: IC DC/DC CONV SINGLE CELL 8-SOIC
• Manufacturer: Linear Technology
• Type: Step-Up (Boost)r

Specifications of LT1307CS8

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 3.3V, 5V
• Current - Output: 100mA
• Frequency - Switching: 600kHz
• Voltage - Input: 1 ~ 5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

APPLICATIO S I FOR ATIO
underdamping. Now settling time is about 300 s. Increas-
ing C to 680pF results in the response shown in Figure 11e.
This response has minimum settling time with no over-
shoot or underdamping.
Converters using a 2-cell input need more capacitance at
the output. This added capacitance moves in the output
AC COUPLED
AC COUPLED
200mV/DIV
200mV/DIV
Figure 11a. V
Voltage is 300mV
I
Figure 11c. Reducing C to 2nF Speeds Up Response,
Although Still Overdamped
I
L
L
51mA
51mA
V
V
1mA
1mA
OUT
OUT
C
Pin Left Unconnected. Output Ripple
U
P-P
Under Load
U
5ms/DIV
1ms/DIV
AC COUPLED
200mV/DIV
W
Figure 11e. A 100k/680pF RC Provides Optimum
Settling Time with No Ringing
I
L
51mA
V
1mA
OUT
U
1307 F11a
1307 F11a
1ms/DIV
pole, requiring added C at the V
loop oscillation.
Observant readers will notice R has been set to 100k for all
the photos in Figure 11. Usable R values can be found in
the 10k to 500k range, but after too many trips to the
resistor bins, 100k wins.
AC COUPLED
AC COUPLED
200mV/DIV
200mV/DIV
Figure 11b. Inclusion of a 100k/22nF Series RC on V
Pin Results in Overdamped Stable Response
I
Figure 11d. A 100k/200pF Series RC Shows Some
Underdamping
I
L
L
51mA
51mA
V
1mA
V
1mA
OUT
OUT
1307 F11b
500 s/DIV
5ms/DIV
LT1307/LT1307B
C
pin network to prevent
1307 F11b
1307 F11b
11
C
1307fa