LTC1624
TYPICAL PERFORMANCE CHARACTERISTICS
U W
ITH/RUN Pin Source Current vs
Temperature
VITH vs Output Current
IITH vs VITH
300
250
200
150
100
50
5
4
3
2
1
0
200
2.4
I
/RUN = 1V
TH
150
50
I
TH
/RUN = 0V
ACTIVE
MODE
1.2
0.8
ACTIVE
MODE
SHUTDOWN
SHUTDOWN
3
0
0
0
0
I
OUT(MAX)
60
TEMPERATURE (°C)
110 135
–40 –15
10
35
85
0
0.8
1.2
(V)
2.4
I
V
OUT
ITH
1624 G14
(a)
(b)
1624 G01
1624 G02
Operating Frequency vs
Temperature
Maximum Current Sense
Threshold vs Temperature
Frequency vs Feedback Voltage
250
200
150
100
50
250
200
150
100
50
170
168
166
164
162
160
158
156
154
152
150
V
OUT
IN REGULATION
V
= 0V
FB
0
0
0
0.25
0.50
0.75
1.00
1.25
–40
10
35
60
85 110 135
–40
10
35
60
85 110 135
–15
–15
TEMPERATURE (°C)
TEMPERATURE (°C)
FEEDBACK VOLTAGE
1624 G03
1448 G12
1448 G13
U
U
U
PIN FUNCTIONS
SENSE– (Pin 1): Connects to the (–) input for the current
comparator. Built-in offsets between the SENSE– and VIN
pinsinconjunctionwithRSENSE setthecurrenttripthresh-
olds. Do not pull this pin more than 15V below VIN or more
than 0.3V below ground.
shutdownallfunctionsaredisabledandTGpinisheldlow.
VFB (Pin 3): Receives the feedback voltage from an exter-
nal resistive divider across the output.
GND (Pin 4): Ground. Connect to the (–) terminal of COUT
,
the Schottky diode and the (–) terminal of CIN.
ITH/RUN (Pin 2): Combination of Error Amplifier Compen-
sation Point and Run Control Inputs. The current com-
parator threshold increases with this control voltage.
Nominalvoltagerangeforthispinis1.19Vto2.4V.Forcing
this pin below 0.8V causes the device to be shut down. In
SW (Pin 5): Switch Node Connection to Inductor. In step-
down applications the voltage swing at this pin is from a
Schottky diode (external) voltage drop below ground to
VIN.
4
Linear [ Linear ]
