LTC1143LCS-ADJ#PBF Linear Technology, LTC1143LCS-ADJ#PBF Datasheet - Page 5

• Manufacturer Part Number: LTC1143LCS-ADJ#PBF
• Description: IC SW REG STEP-DOWN DUAL 16-SOIC
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LTC1143LCS-ADJ#PBF

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 2
• Voltage - Output: Adjustable
• Current - Output: 50mA
• Frequency - Switching: 400kHz
• Voltage - Input: 3.5 ~ 16 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

TYPICAL PERFORMANCE CHARACTERISTICS
PIN
LTC1143/LTC1143L
SENSE
Comparator. A built-in offset between Pins 1 and 16 in
conjunction with R
for the 3.3V section.
SHUTDOWN 3 (Pin 2): When grounded, the 3.3V section
operates normally. Pulling Pin 2 high holds the MOSFET
off and puts the 3.3V section in micropower shutdown
mode. Requires CMOS logic level signal with t
Do not “float” Pin 2.
GND3 (Pin 3): 3.3V Section Ground. Two independent
ground lines must be routed separately from other grounds
to: 1) the (–) terminal of the 3.3V section output capacitor
and 2) the cathode of the Schottky diode D1 and (–)
terminal of C
P-DRIVE 3 (Pin 4): High Current Drive for Top P-Channel
MOSFET, 3.3V Section. Voltage swing at this pin is from
V
V
decoupled to 5V power ground Pin 11.
C
the operating frequency for the 5V section. (The actual
frequency is also dependent upon the input voltage.)
IN3
IN5
T5
14
12
10
U
8
6
4
2
0
(Pin 6): External capacitor C
20
to ground.
(Pin 5): Supply Pin, 5V Section. Must be closely
Gate Charge Supply Current
FUNCTIONS
+
3 (Pin 1): The (+) Input to the 3.3V Section Current
OPERATING FREQUENCY (kHz)
U
80
IN3
Q
(see Figure 9).
P
140
= 100nC
SENSE 3
Q
U
P
= 29nC
200
sets the current trip threshold
W
LTC1143 G10
T5
260
from Pin 6 to ground sets
U
80
70
60
50
40
30
20
10
0
Off-Time vs V
0
r
, t
f
< 1 s.
V
OUT
1
OUTPUT VOLTAGE (V)
= 3.3V
OUT
2
I
The 5V section current comparator threshold increases
with the Pin 7 voltage.
SENSE
which sets the output voltage for the 5V section. Pin 8 is
also the (–) input for the current comparator on the 5V
section.
SENSE
Comparator. A built-in offset between Pins 9 and 8 in
conjunction with R
for the 5V section.
SHUTDOWN 5 (Pin 10): When grounded, the 5V section
operates normally. Pulling Pin 10 high holds the 5V section
MOSFET off and puts the 5V section in micropower shut-
down mode. Requires CMOS logic level signal with t
Do not “float” Pin 10.
GND5 (Pin 11): 5V Section Ground. Two independent
ground lines must be routed separately from other grounds
to: 1) the (–) terminal of the 5V section output capacitor
and 2) the cathode of the Schottky diode D2 and (–)
terminal of C
P-DRIVE 5 (Pin 12): High Current Drive for Top P-Channel
MOSFET, 5V Section. Voltage swing at this pin is from
V
TH5
IN5
V
3
OUT
(Pin 7): Gain Amplifier Decoupling Point, 5V Section.
V
to ground.
SENSE
= 5V
–
+
5 (Pin 9): The (+) Input to the 5V Section Current
5 (Pin 8): Connects to internal resistive divider
4
= V
LTC1143 G11
OUT
IN5
5
(see Figure 9).
SENSE 5
LTC1143/LTC1143L
175
150
125
100
75
50
25
0
Current Sense Threshold Voltage
0
sets the current trip threshold
LTC1143L-ADJ
20
TEMPERATURE (°C)
40
THRESHOLD
60
THRESHOLD
MAXIMUM
MINIMUM
r
, t
80
f
< 1 s.
LTC1143 G12
5
100