DC/DC Controller. LT1683 Datasheet

LT1683 Controller. Datasheet pdf. Equivalent

Part LT1683
Description Ultralow Noise Push-Pull DC/DC Controller
Feature FEATURES s s s LT1683 Ultralow Noise Push-Pull DC/DC Controller DESCRIPTIO The LT ®1683 is a switch.
Manufacture Linear Technology
Datasheet
Download LT1683 Datasheet




LT1683
FEATURES
s Greatly Reduced Conducted and Radiated EMI
s Low Switching Harmonic Content
s Independent Control of Output Switch Voltage and
Current Slew Rates
s Greatly Reduced Need for External Filters
s Dual N-Channel MOSFET Drivers
s 20kHz to 250kHz Oscillator Frequency
s Easily Synchronized to External Clock
s Regulates Positive and Negative Voltages
s Easier Layout Than with Conventional Switchers
U
APPLICATIO S
s Power Supplies for Noise Sensitive Communication
Equipment
s EMI Compliant Offline Power Supplies
s Precision Instrumentation Systems
s Isolated Supplies for Industrial Automation
s Medical Instruments
s Data Acquisition Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
LT1683
Ultralow Noise
Push-Pull DC/DC Controller
DESCRIPTIO
The LT®1683 is a switching regulator controller designed
to lower conducted and radiated electromagnetic interfer-
ence (EMI). Ultralow noise and EMI are achieved by
controlling the voltage and current slew rates of external
N-channel MOSFET switches. Current and voltage slew
rates can be independently set to optimize harmonic
content of the switching waveforms vs efficiency. The
LT1683 can reduce high frequency harmonic power by as
much as 40dB with only minor losses in efficiency.
The LT1683 utilizes a dual output (push-pull) current
mode architecture optimized for low noise topologies. The
IC includes gate drivers and all necessary oscillator,
control and protection circuitry. Unique error amp cir-
cuitry can regulate both positive and negative voltages.
The oscillator may be synchronized to an external clock for
more accurate placement of switching harmonics.
Protection features include gate drive lockout for low VIN,
opposite gate lockout, soft-start, output current limit,
short-circuit current limiting, gate drive overvoltage clamp
and input supply undervoltage lockout.
TYPICAL APPLICATIO
Ultralow Noise 48V to 5V DC/DC Converter
51k
1N4148
510
0.5W
FZT853
10µF
20V
2N3904
8.2V
48V
39µF
63V
MIDCOM 31244
MBR0530
MBRS340
11V 68µF
20V 17 3
23.2k
976
1.2nF
16.9k
25k 3.3k
25k 3.3k
1.5k
0.22µF 22nF
VIN GCL
5pF
14
SHDN
5
V5
6
SYNC
2
CAP A
1
GATE A
5pF
7
CT
18
CAP B
8
RT
LT1683
19
GATE B
16
RVSL
4 Si9422
CS
15
RCSL
20
PGND
12
VC
9
FB
SS GND NFB
13 11 10
10nF
10pF
200V
Si9422
MBRS340
10pF
200V
30pF
0.1
30pF
22µH
150µF
OS-CON
OPTIONAL
B 22µH
A 5V/2A
2×100µF
POSCAP
7.50k
2.49k
A
200µV/DIV
B
20mV/DIV
1683 TA01
5V Output Noise
(Bandwidth = 100MHz)
200µVP-P
5µs/DIV
1683 TA01a
1683f
1



LT1683
LT1683
ABSOLUTE AXI U RATI GS
(Note 1)
Supply Voltage (VIN) ................................................ 20V
Gate Drive Current ..................................... Internal Limit
V5 Current ................................................. Internal Limit
SHDN Pin Voltage .................................................... 20V
Feedback Pin Voltage (Trans. 10ms) ...................... ±10V
Feedback Pin Current ............................................ 10mA
Negative Feedback Pin Voltage (Trans. 10ms) ........ ±10V
CS Pin .......................................................................... 5V
GCL Pin ..................................................................... 16V
SS Pin .......................................................................... 3V
Operating Junction Temperature Range
(Note 3) ............................................ – 40°C to 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
GATE A 1
CAP A 2
GCL 3
CS 4
V5 5
SYNC 6
CT 7
RT 8
FB 9
NFB 10
20 PGND
19 GATE B
18 CAP B
17 VIN
16 RVSL
15 RCSL
14 SHDN
13 SS
12 VC
11 GND
ORDER PART
NUMBER
LT1683EG
LT1683IG
G PACKAGE
20-LEAD PLASTIC SSOP
TJMAX = 150°C, θJA = 110°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VC = 0.9V, VFB = VREF, RVSL, RCSL = 16.9k, RT = 16.9k and
other pins open unless otherwise noted.
SYMBOL PARAMETER
Error Amplifiers
VREF
IFB
FBREG
VNFR
Reference Voltage
Feedback Input Current
Reference Voltage Line Regulation
Negative Feedback Reference Voltage
INFR
NFBREG
gm
Negative Feedback Input Current
Negative Feedback Reference Voltage Line Regulation
Error Amplifier Transconductance
CONDITIONS
Measured at Feedback Pin
VFB = VREF
2.7V VIN 20V
Measured at Negative Feedback Pin
with Feedback Pin Open
VNFB = VNFR
2.7V VIN 20V
IC = ±50µA
IESK
IESRC
VCLH
VCLL
AV
FBOV
ISS
Error Amp Sink Current
Error Amp Source Current
Error Amp Clamp Voltage
Error Amp Clamp Voltage
Error Amplifier Voltage Gain
FB Overvoltage Shutdown
Soft-Start Charge Current
VFB = VREF + 150mV, VC = 0.9V
VFB = VREF – 150mV, VC = 0.9V
High Clamp, VFB = 1V
Low Clamp, VFB = 1.5V
Outputs Drivers Disabled
VSS = 1V
MIN TYP MAX UNITS
q 1.235
q
q
q – 2.56
1.250
250
0.012
– 2.500
1.265
1000
0.03
– 2.45
V
nA
%/V
V
– 37
q
1100
q 700
q 120
q 120
180
– 25
0.009
1500
200
200
1.27
0.12
250
1.47
9.0
0.03
2200
2500
350
350
12
µA
%/V
µmho
µmho
µA
µA
V
V
V/V
V
µA
1683f
2







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