LT1161CN Linear Technology, LT1161CN Datasheet - Page 9

• Manufacturer Part Number: LT1161CN
• Description: IC MOSFET DRIVER N-CH QUAD 20DIP
• Manufacturer: Linear Technology

Specifications of LT1161CN

• Configuration: High-Side
• Input Type: Non-Inverting
• Delay Time: 220µs
• Number Of Configurations: 4
• Number Of Outputs: 4
• Voltage - Supply: 8 V ~ 48 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Peak: -
• High Side Voltage - Max (bootstrap): -

APPLICATIONS
TYPICAL APPLICATIONS
Current sensing for protecting low-side drivers can be
done in several different ways. In the Figure 9a circuit, the
supply voltage for the load is assumed to be within the
1µF
1µF
Figure 9b. Low-Side Drivers with Two Approaches
for Source Current Sensing
T1
T2
(MAY BE PARALLELED)
V
+
LT1161
V
DS2
DS1
+
G1
G2
U
INPUTS
2N2222
2N2222
51Ω
Using an Extra Channel to Do Common Current Limit for Multiple/Paralleled Switches
INFORMATION
U
1N4148
51Ω
51Ω
8V TO 24V
1µF
LT1013
1/2
U
1N4744
+
–
100k
W
15V
10µF
1N4744
LOAD
15V
HV
10
1
2
3
4
5
6
7
8
9
IRF630
R
0.2Ω
U
HV
S1
GND
T1
IN1
T2
IN2
T3
IN3
T4
IN4
GND
LOAD
HV
1161 F09b
LT1161
IRF630
R
0.02Ω
S2
DS1
DS2
DS3
DS4
V
G1
G2
G3
G4
V
+
+
supply operating range of the LT1161. This allows the load
to be returned to supply through current-sense resistor
R
circuitry.
If the load cannot be returned to supply through R
load supply voltage is higher than the LT1161 supply, the
current sense must be moved to the source of the low-side
MOSFET. Figure 9b shows two approaches to source
sensing. On channel 1, current limit occurs when the
voltage across sense resistor R
NPN transistor, causing the LT1161 drain sense pin to be
pulled down.
The channel 2 circuit of Figure 9b uses an operational
amplifier (must common mode to ground) to level shift the
voltage across R
proach allows the use of a much smaller sense resistor
which could be made from PC trace material. In both
cases, the LT1161 restart timers function the same as in
high-side switch applications.
20
19
18
17
16
15
14
13
12
11
S
, providing normal operation of the LT1161 protection
15k
IRFZ44
IRFZ44
IRFZ44
S2
24V
up to the drain sense pin. This ap-
R
S
10µF
50V
S1
thresholds the V
OUTPUTS
(MAY BE PARALLELED)
1161 TA05
LT1161
S
BE
, or the
of the
1161fa
9