LT1576CS8-SYNC#TRPBF Linear Technology, LT1576CS8-SYNC#TRPBF Datasheet - Page 22
![IC SW REG STEP-DOWN 200KHZ 8SOIC](/photos/7/57/75766/lt1576cs8_sml.jpg)
LT1576CS8-SYNC#TRPBF
Manufacturer Part Number
LT1576CS8-SYNC#TRPBF
Description
IC SW REG STEP-DOWN 200KHZ 8SOIC
Manufacturer
Linear Technology
Type
Step-Down (Buck)r
Datasheet
1.LT1576CS8PBF.pdf
(28 pages)
Specifications of LT1576CS8-SYNC#TRPBF
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
Adj to 1.2V
Current - Output
1.5A
Frequency - Switching
200kHz
Voltage - Input
5 ~ 25 V
Operating Temperature
0°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LT1576CS8-SYNC#TRPBFLT1576CS8-SYNC#PBF
Manufacturer:
LINEAR/凌特
Quantity:
20 000
LT1576/LT1576-5
APPLICATIONS
How Do I Test Loop Stability?
The “standard” compensation for LT1576 is a 100pF
capacitor for C
will work for most applications, the “optimum” value for
loop compensation components depends, to various ex-
tent, on parameters which are not well controlled. These
include inductor value ( 30% due to production toler-
ance, load current and ripple current variations), output
capacitance ( 20% to 50% due to production tolerance,
temperature, aging and changes at the load), output
capacitor ESR ( 200% due to production tolerance, tem-
perature and aging), and finally, DC input voltage and
output load current . This makes it important for the
designer to check out the final design to ensure that it is
“robust” and tolerant of all these variations.
22
C
, with R
INPUT SUPPLY
ADJUSTABLE
U
C
INFORMATION
= 0 . While this compensation
U
10mV/DIV
REGULATOR
SWITCHING
W
5A/DIV
ADJUSTABLE
DC LOAD
Figure 13. Loop Stability Test Circuit
Figure 14. Loop Stability Check
U
+
0.2ms/DIV
50
100Hz TO 1kHz
100mV TO 1V
100 F TO
1000 F
TO
OSCILLOSCOPE
SYNC
I check switching regulator loop stability by pulse loading
the regulator output while observing transient response at
the output, using the circuit shown in Figure 13. The
regulator loop is “hit” with a small transient AC load
current at a relatively low frequency, 50Hz to 1kHz. This
causes the output to jump a few millivolts, then settle back
to the original value, as shown in Figure 14. A well behaved
loop will settle back cleanly, whereas a loop with poor
phase or gain margin will “ring” as it settles. The number
of rings indicates the degree of stability, and the frequency
of the ringing shows the approximate unity-gain fre-
quency of the loop. Amplitude of the signal is not particu-
larly important, as long as the amplitude is not so high that
the loop behaves nonlinearly.
P-P
3300pF
470
1576 F14
RIPPLE FILTER
4.7k
V
I
BEFORE FILTER
V
I
AFTER FILTER
LOAD PULSE
THROUGH 50
f 780Hz
V
I
AFTER FILTER
OUT
OUT
OUT
OUT
OUT
OUT
= 50mA
= 500mA
= 500mA
AT
AT
AT
330pF
1576 F13
TO X1
OSCILLOSCOPE
PROBE