LTC3851A_15 Datasheet, PDF (30/30 Pages) Linear Technology – Synchronous Step-Down Switching Regulator Controller

LTC3851A
Typical Application
R_FREQ
160k
MODE/PLLIN V_IN
FREQ/PLLFLTR TG
V_IN
4.5V TO 22V
C_B
0.1µF
+ C_IN
22µF
M1A
25V
FDS6982S
0.1µF
C_SS
0.1µF
R_C
C_C
470pF
33k
C_C2
220pF
RUN
BOOST
LTC3851A
TK/SS
SW
I_TH
INTV_CC
V_FB
BG
SENSE^–
GND
D_B
CMDSH-3
L1
3.3µH
4.7µF
M1B
FDS6982S
R_SENSE
0.01Ω
R2
32.4k
1% +
R1
25.5k
1%
V_OUT
1.8V
5A
C_OUT
150µF
6.3V
×2
PANASONIC SP
1000pF
10Ω 10Ω
SENSE⁺
I_LIM
C_OUT: PANASONIC EEFUEOG151R
C_IN: MARCON THCR70LE1H226ZT
L1: PANASONIC ETQP6F3R3HFA
R_SENSE: IRC LR 2010-01-R010F
3851A F13
Figure 13. 1.8V/5A Converter from Design Example with Pulse-Skipping Operation
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
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LTC3775
Small Footprint Wide V_IN Range Synchronous Step-Down DC/
DC Controller
No R_SENSE™ Constant On-Time Synchronous Step-Down DC/
DC Controller
No R_SENSE Constant On-Time Synchronous Step-Down DC/DC
Controller
Dual 2-Phase, High Efficiency Synchronous Step-Down DC/DC
Controllers, R_SENSE or DCR Current Sensing and Tracking
Triple Output, Multiphase Synchronous Step-Down DC/DC
Controller, R_SENSE or DCR Current Sensing and Tracking
12A, 1MHz, Monolithic Synchronous Step-Down DC/DC
Converter
10A, 1MHz, Monolithic Synchronous Step-Down DC/DC
Converter
High Frequency Synchronous Voltage Mode Step-Down DC/DC
Controller
Fixed 400kHz Operating Frequency, 4.5V≤ V_IN ≤ 38V,
0.8V ≤ V_OUT ≤ 5.25V, 2mm × 3mm QFN-12
Very Fast Transient Response, t_ON(MIN) = 43ns, 4V≤ V_IN ≤ 38V,
0.8V ≤ V_OUT ≤ 0.9V_IN, SSOP-16
Very Fast Transient Response, t_ON(MIN) = 43ns, 4V≤ V_IN ≤ 38V,
0.6V ≤ V_OUT ≤ 0.9V_IN, MSOP-16E, 3mm × 3mm QFN-16
Phase-Lockable Fixed Operating Frequency 250kHz to 780kHz,
4V≤ V_IN ≤ 30V, 0.8V ≤ V_OUT ≤ 5.25V
Phase-Lockable Fixed Operating Frequency 250kHz to 750kHz,
4V≤ V_IN ≤ 24V, V_OUT Up to 13.5V
High Efficiency, Adjustable Constant On-Time, 4V≤ V_IN ≤ 24V,
V_OUT(MIN) = 0.6V, 9mm × 9mm QFN-64
High Efficiency, Adjustable Constant On-Time, 4V≤ V_IN ≤ 32V,
V_OUT(MIN) = 0.6V, 9mm × 9mm QFN-64
Synchronizable Fixed Frequency 250kHz to 1MHz,
t_ON(MIN) = 30ns, 4V ≤ V_IN ≤ 38V, 0.6V ≤ V_OUT ≤ 0.8V_IN,
MSOP-16E, 3mm × 3mm QFN-16
30 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ^● FAX: [phone] ^● www.linear.com
3851afa
LT 0611 REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2010