Datasheet

LT6108-1/LT6108-2
10
610812fa
LT6108-2 Comparator Step
Response (5mV INC Overdrive)
LT6108-2 Comparator Step
Response (100mV INC Overdrive)
LT6108-1 Comparator Reset
Response
SENSELO (Pin 1): Sense Amplifier Input. This pin must
be tied to the load end of the sense resistor.
EN/RST (Pin 2, LT6108-1 Only): Enable and Latch Reset
Input. When the EN/RST pin is pulled high the LT6108-1
is enabled. When the EN/RST pin is pulled low for longer
than typically 40µs, the LT6108-1 will enter the shutdown
mode. Pulsing this pin low for between 2µs and 15µs will
reset the comparator of the LT6108-1.
EN (Pin 2, LT6108-2 Only): Enable Input. When the en-
able pin is pulled high the LT6108-2 is enabled. When the
enable pin is pulled low for longer than typically 40µs, the
LT6108-2 will enter the shutdown mode
OUTC (Pin 3): Open-Drain Comparator Output. Off-state
voltage may be as high as 60V above V
–
, regardless of
V
+
used.
V
–
(Pin 4): Negative Supply Pin. This pin is normally con-
nected to ground.
INC (Pin 5): This is the inverting input of the comparator.
The other comparator input is internally connected to the
400mV reference.
PIN FUNCTIONS
OUTA (Pin 6): Current Output of the Sense Amplifier. This
pin will source a current that is equal to the sense voltage
divided by the external gain setting resistor, R
IN
.
V
+
(Pin 7): Positive Supply Pin. The V
+
pin can be con-
nected directly to either side of the sense resistor, R
SENSE
.
When V
+
is tied to the load end of the sense resistor, the
SENSEHI pin can go up to 0.2V above V
+
. Supply current
is drawn through this pin.
SENSEHI (Pin 8): Sense Amplifier Input. The internal
sense amplifier will drive SENSEHI to the same potential
as SENSELO. A resistor (typically R
IN
) tied from supply
to SENSEHI sets the output current, I
OUT
= V
SENSE
/R
IN
,
where V
SENSE
is the voltage developed across R
SENSE
.
Exposed Pad (Pin 9, DCB Package Only): V
–
. The exposed
pad may be left open or connected to device V
–
. Connect-
ing the exposed pad to a V
–
plane will improve thermal
management in high voltage applications. The exposed
pad should not be used as the primary connection for V
–
.
TYPICAL PERFORMANCE CHARACTERISTICS
Performance characteristics taken at T
A
= 25°C,
V
+
= 12V, V
PULLUP
= V
+
, V
EN
= V
EN/RST
= 2.7V, R
IN
= 100Ω, R
OUT
= R1 + R2 = 10k, gain = 100, R
C
= 25.5k, C
L
= C
LC
= 2pF, unless
otherwise noted. (See Figure 3)
V
INC
0.5V/DIV
0V
V
OUTC
1V/DIV
610812 G35
5µs/DIV
0V
V
+
= 5V
V
INC
0.5V/DIV
0V
V
OUTC
1V/DIV
610812 G36
5µs/DIV
0V
V
+
= 5V
0V
V
OUTC
5V/DIV
V
EN/RST
2V/DIV
0V
5µs/DIV
610812 G37