LT1110CS8-5 Linear Technology, LT1110CS8-5 Datasheet - Page 13

• Manufacturer Part Number: LT1110CS8-5
• Description: IC DC/DC CONV FIXED OUT 5V 8SOIC
• Manufacturer: Linear Technology
• Type: Step-Down (Buck), Step-Up (Boost)r

Specifications of LT1110CS8-5

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 5V
• Current - Output: 400mA
• Frequency - Switching: 70kHz
• Voltage - Input: 1 ~ 30 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Power - Output: 500mW
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Arrangement of the gain block as a low battery detector is
straightforward. Figure 12 shows hookup. R1 and R2 need
only be low enough in value so that the bias current of the
SET input does not cause large errors. 33k for R2 is
adequate. R3 can be added to introduce a small amount of
hysteresis. This will cause the gain block to “snap” when
the trip point is reached. Values in the 1M-10M range are
optimal. The addition of R3 will change the trip point,
however.
Table 1. Inductor Manufacturers
MANUFACTURER
Coiltronics International
984 S.W. 13th Court
Pompano Beach, FL 33069
305-781-8900
Sumida Electric Co. USA
708-956-0666
A
V
BAT
PPLICATI
Figure 12. Setting Low Battery Detector Trip Point
R1
R2
O
SET
220mV
U
REF
S
I FOR ATIO
–
+
GND
U
V
IN
LT1110
R3
V
R1 =
R2 = 33k
LB
R3 = 2M
W
AO
= BATTERY TRIP POINT
(
V
LB
4.33 A
+5V
– 220mV
PART NUMBERS
CTX100-4 Series
Surface Mount
CD54
CDR74
CDR105
Surface Mount
47k
LT1110 • TA07
)
U
TO
PROCESSOR
Output ripple of the LT1110, normally 90mV at 5V
be reduced significantly by placing the gain block in front
of the FB input as shown in Figure 13. This effectively
reduces the comparator hysteresis by the gain of the gain
block. Output ripple can be reduced to just a few millivolts
using this technique. Ripple reduction works with step-
down or inverting modes as well. For this technique to be
effective, output capacitor C1 must be large, so that each
switching cycle increases V
1000 F is a good starting value.
Table 2. Capacitor Manufacturers
MANUFACTURER
Sanyo Video Components
2001 Sanyo Avenue
San Diego, CA 92173
619-661-6835
Nichicon America Corporation
927 East State Parkway
Schaumberg, IL 60173
708-843-7500
Sprague Electric Company
Lower Main Street
Sanford, ME 04073
207-324-4140
Matsuo
714-969-2491
Table 3. Transistor Manufacturers
MANUFACTURER
Zetex
Commack, NY
516-543-7100
V
BAT
V
Figure 13. Output Ripple Reduction Using Gain Block
OUT
=
(
R2
R1
R3
270k
+ 1 220mV
) (
AO
FB
GND
I
LIM
LT1110
)
V
SW2
IN
SW1
SET
OUT
L1
by only a few millivolts.
D1
PART NUMBERS
OS-CON Series
PL Series
150D Solid Tantalums
550D Tantalex
267 Series
Surface Mount
PART NUMBERS
ZTX Series
FZT Series
Surface Mount
R2
R1
LT1110
+
OUT
13
LT1110 • TA08
C1
can
V
OUT