Datasheet

4
LTC3736-1
37361f
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Efficiency and Power Lost vs
Load Current
LOAD CURRENT (mA)
1 100 1000 10000
37361 G01
10
V
OUT
= 2.5V
V
OUT
= 1.8V
FIGURE 13 CIRCUIT
V
IN
= 5V
POWER LOST (W)
1
10
0.01
0.1
0.001
65
EFFICIENCY (%)
95
100
60
55
90
75
85
80
70
50
V
OUT
AC-COUPLED
100mV/DIV
V
IN
= 3.3V
V
OUT
= 1.8V
I
LOAD
= 300mA TO 3A
SSDIS = GND
FIGURE 15 CIRCUIT
100µs/DIV
37361 G02
I
L
2A/DIV
V
OUT
AC-COUPLED
100mV/DIV
V
IN
= 3.3V
V
OUT
= 1.8V
I
LOAD
= 300mA TO 3A
SSDIS = V
IN
FIGURE 15 CIRCUIT
100µs/DIV
37361 G03
I
L
2A/DIV
Load Step
(Spread Spectrum Enabled)
Load Step
(Spread Spectrum Disabled)
Input Voltage Noise
(Spread Spectrum Disabled)
V
IN
= 5V
R
LOAD1
= R
LOAD2
= 1Ω
SSDIS = GND
FIGURE 15 CIRCUIT
200µs/DIV
37361 G06
500mV/
DIV
V
OUT1
2.5V
V
OUT2
1.8V
Input Voltage Noise
(Spread Spectrum Enabled)
Tracking Start-Up with Internal
Soft-Start (C
SS
= 0µF)
V
IN
= 5V
R
LOAD1
= R
LOAD2
= 1Ω
SSDIS = V
IN
FIGURE 15 CIRCUIT
40ms/DIV
37361 G07
500mV/
DIV
V
OUT1
2.5V
V
OUT2
1.8V
INPUT VOLTAGE (V)
2
–5
NORMALIZED FREQUENCY SHIFT (%)
–4
–2
–1
0
5
2
4
6
7
37361 G08
–3
3
4
1
35
8
9
10
SSDIS = V
IN
Oscillator Frequency
vs Input Voltage
Tracking Start-Up with External
Soft-Start (C
SS
= 0.15µF)
T
A
= 25°C unless otherwise noted.
FREQUENCY (Hz)
–80
AMPLITUDE (dBm)
–20
–10
–90
–100
–30
–60
–40
–50
–70
410k 450k 490k 530k 570k 610k
37361 G04
–110
FIGURE 13 CIRCUIT
V
IN
= 5V
V
OUT
= 2.5V
R
BW
= 30Hz
SSDIS = V
IN
FREQUENCY (Hz)
–80
AMPLITUDE (dBm)
–20
–10
–90
–100
–30
–60
–40
–50
–70
410k 450k 490k 530k 570k 610k
37361 G05
–110
FIGURE 13 CIRCUIT
V
IN
= 5V
V
OUT
= 2.5V
R
BW
= 30Hz
SSDIS = GND
Output Voltage Ripple
FIGURE 15 CIRCUIT
ENVELOPE OF 100 SAMPLES
1µs/DIV
37361 G20
50mV/DIV
AC-COUPLED
SSDIS = V
IN
CONSTANT
550kHz
OPERATION
SSDIS = GND
SPREAD
SPECTRUM