LTC3857IUH#TRPBF Linear Technology, LTC3857IUH#TRPBF Datasheet - Page 5

• Manufacturer Part Number: LTC3857IUH#TRPBF
• Description: IC CTRLR STP-DN SYNC DUAL 32QFN
• Manufacturer: Linear Technology
• Series: PolyPhase®r
• Type: Step-Down (Buck)r

Specifications of LTC3857IUH#TRPBF

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 0.8 ~ 24 V
• Frequency - Switching: 50kHz ~ 900kHz
• Voltage - Input: 4 ~ 38 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 32-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -

TYPICAL PERFORMANCE CHARACTERISTICS
SKIPPING MODE
100mV/DIV
INDUCTOR
CURRENT
CONTINUOUS
100
OPERATION
2A/DIV
Burst Mode
0.00001 0.0001
90
80
70
60
50
40
30
20
10
V
0
OUT
FORCED
PULSE-
1A/DIV
Efficiency and Power Loss
vs Output Current
MODE
V
V
FIGURE 13 CIRCUIT
IN
OUT
BURST EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
CCM EFFICIENCY
Load Step (Burst Mode Operation)
V
V
FIGURE 13 CIRCUIT
IN
OUT
= 12V
= 3.3V
= 12V
Inductor Current at Light Load
V
V
I
FIGURE 13 CIRCUIT
LOAD
= 3.3V
IN
OUT
= 12V
OUTPUT CURRENT (A)
0.001
= 3.3V
= 200μA
0.01
20μs/DIV
5μs/DIV
0.1
BURST LOSS
PULSE-SKIPPING
LOSS
CCM LOSS
1
38 57 G01
3857 G04
10
10000
1000
100
10
1
0.1
3857 G07
100mV/DIV
INDUCTOR
CURRENT
2A/DIV
V
FIGURE 13 CIRCUIT
Soft Start-Up
OUT
100
0.00001 0.0001
90
80
70
60
40
20
10
50
30
0
V
V
FIGURE 13 CIRCUIT
Load Step
(Forced Continuous Mode)
IN
OUT
Efficiency vs Output Current
= 12V
= 3.3V
V
IN
= 5V
20ms/DIV
OUTPUT CURRENT (A)
0.001
20μs/DIV
0.01
V
IN
= 12V
V
FIGURE 13 CIRCUIT
OUT
0.1
= 3.3V
3857 G08
1
3857 G05
3857 G02
V
2V/DIV
V
2V/DIV
OUT2
OUT1
10
100mV/DIV
INDUCTOR
CURRENT
FIGURE 13 CIRCUIT
2A/DIV
Tracking Start-Up
92
96
94
90
88
86
84
82
80
98
V
OUT
1
Efficiency vs Input Voltage
Load Step
(Pulse-Skipping Mode)
V
V
FIGURE 13 CIRCUIT
IN
OUT
5
= 12V
= 3.3V
10
20ms/DIV
INPUT VOLTAGE (V)
15
20μs/DIV
LTC3857
20
25
V
I
30
LOAD
OUT
3857 G09
= 3.3V
= 5A
35
3857 G03
V
2V/DIV
V
2V/DIV
3857fc
5
3857 G06
OUT2
OUT1
40