Switching Regulators. LTC1929-PG Datasheet

LTC1929-PG Regulators. Datasheet pdf. Equivalent

Part LTC1929-PG
Description Synchronous Step-Down Switching Regulators
Feature U U FEATURES s 2-Phase Single Output Controller s Reduces Required Input Capacitance and Power Supp.
Manufacture Linear
Datasheet
Download LTC1929-PG Datasheet



LTC1929-PG
FEATURES
s 2-Phase Single Output Controller
s Reduces Required Input Capacitance and Power
Supply Induced Noise
s Current Mode Control Ensures Current Sharing
s Phase-Lockable Fixed Frequency: 150kHz to 300kHz
s True Remote Sensing Differential Amplifier
s OPTI-LOOPTM Compensation Improves Transient
Response
s ±1% Output Voltage Accuracy
s Power Good Output Voltage Monitor (LTC1929-PG)
s Wide VIN Range: 4V to 36V Operation
s Very Low Dropout Operation: 99% Duty Cycle
s Adjustable Soft-Start Current Ramping
s Internal Current Foldback
s Short-Circuit Shutdown Timer with Defeat Option
s Overvoltage Soft-Latch Eliminates Nuisance Trips
s Available in 28-Lead SSOP Package
U
APPLICATIO S
s Desktop Computers
s Internet/Network Servers
s Large Memory Arrays
s DC Power Distribution Systems
LTC1929/LTC1929-PG
2-Phase, High Efficiency,
Synchronous Step-Down
Switching Regulators
DESCRIPTIO
The LTC®1929/LTC1929-PG are 2-phase, single output,
synchronous step-down current mode switching regula-
tor controllers that drive N-channel external power MOSFET
stages in a phase-lockable fixed frequency architecture.
The 2-phase controllers drive their two output stages out
of phase at frequencies up to 300kHz to minimize the RMS
ripple currents in both input and output capacitors. The
2-phase technique effectively multiplies the fundamental
frequency by two, improving transient response while
operating each channel at an optimum frequency for
efficiency. Thermal design is also simplified.
An internal differential amplifier provides true remote
sensing of the regulated supply’s positive and negative
output terminals as required by high current applications.
The RUN/SS pin provides soft-start and a defeatable,
timed, latched short-circuit shutdown to shut down both
channels. Internal foldback current limit provides protec-
tion for the external synchronous MOSFETs in the event of
an output fault. OPTI-LOOP compensation allows the
transient response to be optimized over a wide range of
output capacitance and ESR values.
, LTC and LT are registered trademarks of Linear Technology Corporation.
OPTI-LOOP is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
0.1µF
0.1µF
VIN TG1
BOOST1
LTC1929 SW1
RUN/SS
BG1
1000pF
10k
100pF
ITH
PGND
SENSE1+
SENSE1
TG2
SGND
BOOST2
16k
16k
VDIFFOUT
EAIN
VOS–
VOS+
SW2
BG2
INTVCC
SENSE2+
SENSE2
10
0.47µF
0.47µF
10µF
10µF
35V
CERAMIC
×4
L1
1µH
D1
0.002
L2
D2 1µH
0.002
COUT: T510E108K004AS L1, L2: CEPH149-1ROMC
Figure 1. High Current 2-Phase Step-Down Converter
VIN
5V TO 28V
VOUT
1.6V/40A
+ COUT
1000µF
4V
×2
1929 F01
1



LTC1929-PG
LTC1929/LTC1929-PG
ABSOLUTE AXI U RATI GS
(Note 1)
Input Supply Voltage (VIN).........................36V to – 0.3V
Topside Driver Voltages (BOOST1,2) .........42V to – 0.3V
Switch Voltage (SW1, 2) .............................36V to – 5 V
SENSE1+, SENSE2 +, SENSE1,
SENSE2 Voltages ........................ (1.1)INTVCC to – 0.3V
EAIN, VOS+, VOS–, EXTVCC, INTVCC,
RUN/SS, AMPMD Voltages ..........................7V to – 0.3V
Boosted Driver Voltage (BOOST-SW) ..........7V to – 0.3V
PLLFLTR, PLLIN, VDIFFOUT Voltages .... INTVCC to – 0.3V
ITH Voltage ................................................2.7V to – 0.3V
Peak Output Current <1µs(TGL1,2, BG1,2) ................ 3A
INTVCC RMS Output Current ................................ 50mA
Operating Ambient Temperature Range
LTC1929C .................................................. 0°C to 85°C
LTC1929I .............................................. – 40°C to 85°C
Junction Temperature (Note 2) ............................. 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RUN/SS
SENSE1+
SENSE1
1
2
3
EAIN 4
PLLFLTR 5
PLLIN 6
NC 7
ITH 8
SGND 9
VDIFFOUT 10
VOS– 11
VOS+ 12
SENSE213
SENSE2+ 14
28 NC
27 TG1
26 SW1
25 BOOST1
24 VIN
23 BG1
22 EXTVCC
21 INTVCC
20 PGND
19 BG2
18 BOOST2
17 SW2
16 TG2
15 AMPMD*
G PACKAGE
28-LEAD PLASTIC SSOP
*PGOOD ON LTC1929-PG
TJMAX = 125°C, θJA = 95°C/W
Consult factory for Military grade parts.
ORDER PART
NUMBER
LTC1929CG
LTC1929CG-PG
LTC1929IG
LTC1929IG-PG
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 15V, VRUN/SS = 5V unless otherwise noted.
SYMBOL
PARAMETER
Main Control Loop
VEAIN
VSENSEMAX
Regulated Feedback Voltage
Maximum Current Sense Threshold
IINEAIN
VLOADREG
Feedback Current
Output Voltage Load Regulation
VREFLNREG
VOVL
UVLO
gm
gmOL
IQ
IRUN/SS
VRUN/SS
VRUN/SSLO
Reference Voltage Line Regulation
Output Overvoltage Threshold
Undervoltage Lockout
Transconductance Amplifier gm
Transconductance Amplifier Gain
Input DC Supply Current
Normal Mode
Shutdown
Soft-Start Charge Current
RUN/SS Pin ON Threshold
RUN/SS Pin Latchoff Arming
CONDITIONS
(Note 3); ITH Voltage = 1.2V
VSENSE = 5V
VSENSE1, 2 = 5V, LTC1929 Only
(Note 3)
(Note 3)
Measured in Servo Loop; ITH Voltage = 0.7V
Measured in Servo Loop; ITH Voltage = 2V
VIN = 3.6V to 30V (Note 3)
Measured at VEAIN
VIN Ramping Down
ITH = 1.2V; Sink/Source 5µA; (Note 3)
ITH = 1.2V; (gmxZL; No Ext Load); (Note 3)
(Note 4)
EXTVCC Tied to VOUT; VOUT = 5V
VRUN/SS = 0V
VRUN/SS = 1.9V
VRUN/SS Rising
VRUN/SS Rising from 3V
MIN TYP MAX UNITS
q 0.792
q 62
65
0.800
75
75
–5
0.808
88
85
– 50
V
mV
mV
nA
q
0.05 0.5
%
q
– 0.1 – 0.5
%
0.002 0.02
%/V
0.84 0.86 0.88
V
3 3.5 4
V
3 mmho
1.5 V/mV
470
20
– 0.5 –1.2
1.0 1.5
4.1
40
1.9
4.5
µA
µA
µA
V
V
2





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