LTC1842CS8 Linear Technology, LTC1842CS8 Datasheet - Page 8

• Manufacturer Part Number: LTC1842CS8
• Description: IC COMP ULTLOPWR W/REF DUAL8SOIC
• Manufacturer: Linear Technology
• Type: with Voltage Referencer

Specifications of LTC1842CS8

• Number Of Elements: 2
• Output Type: Open Drain
• Voltage - Supply: 2.5 V ~ 11 V, ±1.25 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC1841/LTC1842/LTC1843
APPLICATIONS
8
Hysteresis
Hysteresis can be added to the LTC1842/LTC1843 by
connecting a resistor (R1) between the REF and HYST pins
and a second resistor (R2) from HYST to V
The difference between the upper and lower threshold
voltages, or hysteresis voltage band (V
the voltage difference between the REF and HYST pins.
As more hysteresis is added, the upper threshold in-
creases the same amount as the low threshold decreases.
The maximum voltage allowed between REF and HYST
pins is 50mV, producing a maximum hysteresis voltage
band of 100mV. The hysteresis band may vary by up to
5V
TO
8V
V
Figure 3a. Power Supply Transient Test Circuit
+
V
R3
2.4M
OUT
Figure 3b. Power Supply Transient Rejection
REF
10k
8V
5V
R2
R1
430
C1
1 F
U
3
5
6
IN A
HYST
REF
INFORMATION
+
2ms/DIV
U
V
2
–
+
–
V
+
7
W
HB
LTC1843
1841/1843 F03b
1841/43 F03a
), is equal to twice
OUT A
–
(Figure 4).
1
U
5V
1M
OUT A
15%. If hysteresis is not wanted, the HYST pin should be
shorted to REF. Acceptable values for I
0.1 A to 5 A. If 2.4M is chosen for R2, then the value of
R1 is equal to the value of V
Window Detector
The LTC1843 is ideal for use as a micropower window
detector as shown in Figure 5. The values of R1, R2 and R3
are selected for a 4.5V undervoltage threshold and a 5.5V
overvoltage threshold. R4 and R5 set the hysteresis volt-
age. The following design procedure can be used to select
the component values:
V
IN
R3
1M
R2
62.2k
R1
294k
I
REF
R1
R2
Figure 4. Programmable Hysteresis
R5
10k
R4
2.4M
Figure 5. Dual Level Detector
6
5
3
5
6
4
HYST
REF
IN A
HYST
REF
IN B
+
–
LTC1843
V
V
2
–
–
2
–
–
+
+
HB
V
5V
.
+
7
LTC1843
R1 =
R2 =
OUT A 1
OUT B
1841/43 F05
(2)(I
REF
1.182V –
V
HB
REF
I
range are from
REF
8
)
1841/43 F04
V
V
V
OTH
UTH
2
HB
1M
= 5.5V
= 4.5V