Datasheet

3
LTC1622
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
PDRV t
r
Gate Drive Rise Time C
LOAD
= 3000pF 80 140 ns
PDRV t
f
Gate Drive Fall Time C
LOAD
= 3000pF 100 140 ns
∆V
SENSE(MAX)
Maximum Current Sense Voltage ● 80 110 140 mV
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC1622CS8; T
J
= T
A
+ (P
D
• 150°C/W),
LTC1622CMS8; T
J
= T
A
+ (P
D
• 250°C/W)
Note 3: The LTC1622 is tested in a feedback loop that servos V
FB
to the
feedback point for the error amplifier (V
ITH
= 0.8V).
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
SUPPLY VOLTAGE (V)
23
SHUTDOWN CURRENT (µA)
10
1622 G01
45
67
89
45
40
35
30
25
20
15
10
5
0
DUTY CYCLE (%)
20 30
TRIP VOLTAGE (mV)
100
1622 G03
40 50
60 70
80 90
110
100
90
80
70
60
50
40
30
V
IN
= 4.2V
UNSYNC
TEMPERATURE (°C)
–55 –35
UNDERVOLTAGE LOCKOUT VOLTAGE (V)
125
1622 G06
–15 5
25 45 65
85 105
2.10
2.05
2.00
1.95
1.90
1.85
1.80
1.75
RUN/SS Current vs Supply Voltage
SUPPLY VOLTAGE (V)
2
SOFT-START CURRENT (µA)
8
1622 G02
46 10
3.50
3.00
2.50
2.00
1.50
1.00
3579
TEMPERATURE (°C)
–55 –35
REFERENCE VOLTAGE (V)
125
1622 G05
–15 5
25 45 65
85 105
0.810
0.805
0.800
0.795
0.790
0.785
0.780
0.775
V
IN
= 4.2V
Shutdown Current
vs Supply Voltage
Maximum Current Sense Voltage
vs Duty Cycle
Undervoltage Lockout Voltage
vs Temperature
Reference Voltage
vs Temperature
TEMPERATURE (°C)
–55 –35
NORMALIZED FREQUENCY (%)
125
1622 G04
–15 5
25 45 65
85 105
10.0
7.5
5.0
2.5
0
–2.5
–5.0
–7.5
–10.0
V
IN
= 4.2V
Normalized Oscillator Frequency
vs Temperature
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 4.2V