LTC3734
Single-Phase,
High Efficiency DC/DC
Controller for Intel Mobile CPUs
FEATURES
■
■
■
■
■
■
■
■
■
■
■
■
■
■
DESCRIPTIO
Wide Input Voltage Range: 4V to 30V
±1%
Output Voltage Accuracy
6-Bit IMVP-IV VID Code: V
OUT
= 0.7V to 1.708V
Intel Compatible Power Saving Mode (PSIB)
Power Good Output with Adaptive Masking
Lossless Voltage Positioning
Resistor Programmable V
OUT
at Boot-Up and
Deeper Sleep State
Resistor Programmable Deep Sleep Offset
Programmable Fixed Frequency: 210kHz to 550kHz
Adjustable Soft-Start Current Ramping
Foldback Output Current Limit
Short-Circuit Shutdown Timer with Defeat Option
Overvoltage Protection
Available in 32-Lead 5mm
×
5mm
×
0.8mm (Profile)
QFN Package
The LTC
®
3734 is a single-phase synchronous step-down
switching regulator controller that drives all N-channel
power MOSFETs in a constant frequency architecture. The
output voltage is programmable by six VID bits during
normal operation and by external resistors during initial
boot-up and deeper sleep state. The LTC3734 drives its
output stage at frequencies up to 550kHz. Powerful on-
chip gate drivers eliminate the need for external gate driver
ICs, thus simplifying the design.
An Intel compatible PSIB input is provided to select between
two modes of operation. Fully enhanced synchronous mode
achieves a very small output ripple and very fast transient
response while power saving mode realizes very high ef-
ficiency. OPTI-LOOP
®
compensation allows the transient
response to be optimized for a wide range of output capaci-
tance and ESR values.
The LTC3734 is available in a small 5mm
×
5mm QFN
package. For 2-phase applications refer to the LTC3735.
, LTC and LT are registered trademarks of Linear Technology Corporation.
OPTI-LOOP is a registered trademark of Linear Technology Corporation.
APPLICATIO S
■
■
Mobile and Desktop Computers
Internet Servers
TYPICAL APPLICATIO
MCH_PG
DPRSLPVR
STP_CPUB
PSIB
FREQSET
6-BIT VID
VID5-VID0
TG
SW
BG
PGND
SENSE
+
SENSE
–
M1
0.8μH
D1
0.002Ω
M2
100pF
R
C
3k
C
C
680pF
0.1μF
PGOOD
LTC3734
RBOOT
I
TH
RDPRSLP
RUN/SS
RDPSLP
SGND
V
OA+
OAOUT
V
OA–
12.7k
56.2k
1.27M
13.3k
13.3k
1.27M
4.5V TO 7V
4.7μF BAT54A
PV
CC
BOOST
0.47μF
SW
SV
CC
4.5V TO 7V
0.1μF
3734 F01
Figure 1. High Current Step-Down Converter
3734f
U
C
IN
10μF
35V
×4
V
IN
5V TO 24V
U
U
+
C
OUT
270μF
2V
×3
V
OUT
0.7V TO 1.708V
20A
1
LINER [ LINEAR TECHNOLOGY ]
