Datasheet
LTC3601
4
3601fb
TYPICAL PERFORMANCE CHARACTERISTICS
Effi ciency vs Load Current
Burst Mode Operation
Effi ciency vs Load Current
Forced Continuous Mode
Effi ciency vs Frequency
Forced Continuous Mode
Reference Voltage vs
Temperature
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3601 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3601E is guaranteed to meet specifi cations from
0°C to 85°C junction temperature. Specifi cations over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3601I is guaranteed over the full –40°C to 125°C operating junction
temperature range. Note that the maximum ambient temperature
consistent with these specifi cations is determined by specifi c operating
Effi ciency vs Input Voltage
Burst Mode Operation
conditions in conjunction with board layout, the rated package thermal
impedance and other environmental factors.
Note 3: T
J
is calculated from the ambient temperature, T
A
, and power
dissipation, P
D
, according to the following formula:
T
J
= T
A
+ (P
D
• θ
JA
)
where θ
JA
= 45°C/W for the QFN package and θ
JA
= 38°C/W for the MSOP
package.
Note 4: Maximum allowed current draw when used as a regulated output
is 5mA. This supply is only intended to provide additional DC load current
as needed and not intended to regulate large transient or ac behavior as
these waveforms may impact LTC3601 operation.
Effi ciency vs Load Current
T
A
= 25°C, V
IN
= 12V, f
O
= 1MHz, L = 2.2μH unless otherwise noted.
LOAD CURRENT (A)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.001 0.1 1 10
3601 G01
0
0.01
V
IN
= 4V
V
IN
= 8V
V
IN
= 12V
V
OUT
= 1.8V
LOAD CURRENT (A)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.001 0.1 1 10
3601 G02
0
0.01
V
IN
= 4V
V
IN
= 8V
V
IN
= 12V
V
OUT
= 1.8V
LOAD CURRENT (A)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.001 0.1 1 10
3601 G03
0
0.01
V
OUT
= 3.3V
V
OUT
= 5V
BURST
FORCED
CONTINUOUS
INPUT VOLTAGE (V)
4
EFFICIENCY (%)
75
80
85
10
14
3601 G04
70
65
60
68 12
90
95
100
16
I
LOAD
= 500mA
I
LOAD
= 100mA
V
OUT
= 1.8V
FIGURE 7 CIRCUIT
I
LOAD
= 1.5A
I
LOAD
= 10mA
FREQUENCY (MHz)
0.5
80
EFFICIENCY (%)
82
84
86
88
90
92
1.0 1.5 2.0 2.5
3601 G05
3.0
L = 2.2µH
V
OUT
=1.8V
I
LOAD
= 500mA
L = 1µH
TEMPERATURE (°C)
–50 –25
0.595
V
REF
(V)
0.599
0.605
0
50
75
3601 G06
0.597
0.603
0.601
25
100
125