YB1696
150KHz, 3A PWM Buck Switching Regulator
Description
The YB1696 series are monolithic
integrated circuits that provide all the active
functions for a step-down DC/DC converter,
capable of driving a 3A load without
additional transistor component. Requiring
a minimum number of external component,
the board space can be saved easily. The
external shutdown function can be
controlled by TTL logic level and then come
into standby mode. The internal
compensation makes feedback control
have good line and load regulation without
external design. Regarding protected
function, thermal shutdown is to prevent
over temperature operating from damage,
and current limit is against over current
operating of the output switch. The YB1696
series operates at a switching frequency of
150KHz thus allowing smaller sized filter
components than what would be needed
with lower frequency switching regulators.
Other features include a guaranteed +4%
tolerance on output voltage under specified
input voltage and output load conditions,
and +15% on the oscillator frequency. The
output version included fixed 5V and an
adjustable type. The package is available in
a standard 5-lead TO-263(S).
Typical Application Circuit
Features
5V and adjustable output versions
Adjustable version output voltage
range, 1.23V to 28V +4% max over
line and load condition
Available in TO263-5L packages
Voltage mode non-synchronous PWM
control
Thermal-shutdown and current-limit
protection
ON/OFF shutdown control input
Input voltage range up to 32V
Output load current: 3A
150 KHz fixed frequency internal
oscillator
Low power standby mode
Built-in switching transistor on chip
Applications
Simple High-efficiency step-down
regulator
Efficient preregulator for linear
regulators
On-card switching regulators
Positive to negative converter
Battery charger
YB1696 MRev.1.1 www.yobon.com.tw 1
YB1696
150KHz, 3A PWM Buck Switching Regulator
Pin Configuration
Pin Description
Tab le 1
Pin Name Pin Function
VIN
OUTPUT
GND
FB
SD
Operating voltage input
Switching output
Ground
Output voltage feedback control
ON/OFF Shutdown
YB1696 MRev.1.1 www.yobon.com.tw 2
YB1696
150KHz, 3A PWM Buck Switching Regulator
Ordering Information
YB1696-50 : For Fixed Output Voltage of 5.0V
YB1696-ADJ : For External Adjustable Version
Marking Information
YB1696-50 : For Fixed Output Voltage of 5.0V
YB1696-ADJ : For External Adjustable Version
Absolute Maximum Ratings
Symbol Parameter Rating Unit
VCC Supply Voltage +34 V
VSD ON/OFF Pin input voltage -0.3 to +25 V
VFB Feedback Pin voltage -0.3 to +25 V
V
Output voltage to Ground -1 V
OUT
PD Power dissipation Internally limited W
TST Storage temperature -65 to +150
TOP Operating temperature -40 to +125
VOP Operating voltage +4.5 to +25 V
o
C
o
C
YB1696 MRev.1.1 www.yobon.com.tw 3
YB1696
A
150KHz, 3A PWM Buck Switching Regulator
Electrical Characteristics
Unless otherwise specified, VIN=12V for 3.3V, 5V, adjustable version. I
Symbol Parameter Conditions Min. Typ. Max. Unit
IB
F
OSC
Feedback bias
current
oscillator frequency
V
saturation voltage
SAT
DC
Max. Duty Cycle(ON) VFB=0V force driver on 100
Min. Duty cycle(OFF)
ICL current limit
IL
IQ Quiescent Current VFB=12 force driver off 5 10 mA
I
STBY
Output = 0
Output = 1
Standby Quiescent
Current
Output
leakage
current
VFB=1.3V
(Adjustable version
only)
I
=3A
OUT
no outside circuit
VFB=0V force driver on
VFB=12V force driver
off
peak current
no outside circuit
VFB=0 force driver on
no outside circuit
VFB=12 force driver off
VIN=32V 2 60 mA
ON/OFF pin=5V
VIN=24V
LOAD
=0.3
40
127 150 173
110 173
1.3
60
100
1.4
1.5
nA
Khz
V
0
5.5
3.6 4.5
6.5
%
A
200 uA
150
250
uA
300
VIL Low (regulator ON) - 0.6
VIH
ON/OFF pin logic input
threshold voltage
High (regulator OFF) 2.0
1.3
V
-
IH
IL
ΘJC
ΘJA
ON/OFF pin logic
input current
ON/OFF pin input current
Thermal Resistance
Thermal Resistance
With copper area of
approximately 3 in
2
V
V
=2.5V (OFF) 15 25
LOGIC
=0.5V (ON) 0.02 5
LOGIC
Junction to case 3.5
Junction to ambient 23
uA
o
C/W
o
C/W
YB1696 MRev.1.1 www.yobon.com.tw 4
YB1696
150KHz, 3A PWM Buck Switching Regulator
YB1696_ADJ
YB1696_50
Symbol Parameter Conditions Typ. Limit Unit
V
FB
η
V
OUT
η
Output
Feedback
Efficiency V
Output voltage
Efficiency V
5V < VIN < 32V
0.2A <
I
LOAD
V
programmed for 3V
OUT
= 12V, I
IN
8V <
0.2A < I
= 12V, I
IN
LOAD
VIN < 32V
LOAD
LOAD
< 3A
=3A 73 %
< 3A
=3A 80 %
1.23 1.193/1.18
5
1.267/1.28
4.8/4.75
5.2/5.25
V
V
MIN
V
MAX
V
V
MIN
V
MAX
YB1696 MRev.1.1 www.yobon.com.tw 5
Typical Characteristics
Typical Performance Characteristics
Normalized Output Voltage
5.10
VIN=20V, I
Normalized at T
5.05
YB1696
150KHz, 3A PWM Buck Switching Regulator
Efficiency
=3A
LOAD
=25oC
J
100
95
3A Load
5.00
4.95
OUTPUT VOLTAGE CHANGE
4.90
1.7
1.6
1.5
1.4
1.3
SATURATION VOLTAGE (V)
1.2
-50-25 025 5075100125
JUNCTION TEMPERATURE(oC)
Switch Saturation Voltage
1 : -40oC
o
C
2 : 25
o
3 : 125
1
2
3
C
2.0
SWITCH CURRENT(A)
3
45
90
85
EFFICIENCY (%)
80
75
70
5V
3.3V
8101520253035
JUNCTION TEMPERATURE(oC)
40
Switch Current Limit
6.0
VIN=12V, V
5.5
5.0
4.5
SWITCH CURRENT LIMIT (A)
4.0
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE(
OUT
=5V
o
C)
Operating Quiescent Current
25.0
20.0
15.0
Switch ON
10.0
5.0
SUPPLY CURRENT (mA)
0.0
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE(oC)
Switch OFF
200.0
160.0
120.0
CURRENT (uA)
Shutdown Quiescent Current
1
2
80.0
40.0
0.0
3
10 20 30 40
SUPPLY VOLOTAGE (V)
V
ON/OFF
1 : -40
2 : 25
3 : 125
o
o
o
=5V
C
C
C
YB1696 MRev.1.1 www.yobon.com.tw 6
YB1696
150KHz, 3A PWM Buck Switching Regulator
Minimum Operating Supply Voltage
5.0
4.0
3.0
2.0
V
1.0
SUPPLY VOLTAGE (V)
0.0
OUT
I
LOAD
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE (oC)
ON/OFF Pin Current (Sinking)
150.0
VIN=40V
o
-40
CURRENT (uA)
120.0
90.0
60.0
30.0
=1.23V
=120mA
C TJ 125oC
≤≤
ON/OFF Threshold Voltage
5.0
4.0
3.0
2.0
1.0
THRESHOLD VOLTAGE (V)
0.0
-50
JUNCTION TEMPERATURE (oC)
-25
0
Switch Frequency
200.0
150.0
100.0
50.0
FREQUENCY (kHz)
25 50 75
100 125
0.0
1.4 5 10152022232425
ON/OFF PIN VOLTAGE (V)
0.0
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE (oC)
Feedback Pin Bias Current
50.0
40.0
30.0
20.0
Adjustable Version Only
BIAS CURRENT (nA)
10.0
0.0
-50 -25 0 25 50 75 100 125
o
JUNCTION TEMPERATURE(
C)
YB1696 MRev.1.1 www.yobon.com.tw 7
Functional Block Diagram
Current
Source
bias
1.235V
Reference
YB1696
150KHz, 3A PWM Buck Switching Regulator
SD
V
IN
2.5V
Regulator
Start
up
Comp
Comp
200mV
+
_
_
+
220mV
+
Amp
FB
_
Typical Application Circuit
_
Comp
+
150kHz
OSC.
Pre-driver
Thermal
Limit
3A
Switch
Output
Gnd
YB1696 MRev.1.1 www.yobon.com.tw 8
Function Description
YB1696
150KHz, 3A PWM Buck Switching Regulator
Pin Functions
+VIN
This is the positive input supply for the IC
switching regulator. A suitable input bypass
capacitor must be present at this pin to
minimize voltage transients and to supply
the switching currents needed by the
regulator.
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin
switches between (+VIN – V
) and
SAT
approximately – 0.5V, with a duty cycle of
approximately V
/ VIN. To minimize
OUT
coupling to sensitive circuitry, the PC board
open, in either case the regulator will be in
the ON condition.
Thermal Considerations
The YB1696 is available in a 5-pin surface
mount TO-263.
The TO-263 surface mount package tab is
designed to be soldered to the copper on a
printed circuit board. The copper and the
board are the heat sink for this package
and the other heat producing components,
such as the catch diode and inductor. The
PC board copper area that the package is
soldered to should be at least 0.8 in
2
, and
ideally should have 2 or more square
inches of 2 oz. Additional copper area
copper area connected to this pin should
be kept a minimum.
Feedback
Senses the regulated output voltage to
complete the feedback loop.
ON /OFF
Allows the switching regulator circuit to be
shutdown using logic level signals thus
dropping the total input supply current to
approximately 150uA. Pulling this pin below
a threshold voltage of approximately 1.3V
turns the regulator on, and pulling this pin
above 1.3V (up to a maximum of 25V)
shuts the regulator down. If this shutdown
feature is not needed, the ON /OFF pin can
improves the thermal characteristics, but
with copper areas greater than
approximately 6 in2, only small
improvements in heat dissipation are
realized. If further thermal improvements
are needed, double sided, multilayer PC
board with large copper areas and/or
airflow are recommended.
The YB1696 (TO-263 package) junction
temperature rise above ambient
temperature with a 2A load for various input
and output voltages. This data was taken
with the circuit operating as a buck
switching regulator with all components
mounted on a PC board to simulate the
junction temperature under actual
be wired to the ground pin or it can be left
YB1696 MRev.1.1 www.yobon.com.tw 9
operating conditions. This curve can be
YB1696
150KHz, 3A PWM Buck Switching Regulator
used for a quick check for the approximate
junction temperature for various conditions,
but be aware that there are many factors
that can affect the junction temperature.
When load currents higher than 3A are
used, double sided or multilayer PC boards
with large copper areas and/or airflow
might be needed, especially for high
ambient temperatures and high output
voltages.
For the best thermal performance, wide
copper traces and generous amounts of
printed circuit board copper should be used
in the board layout. (Once exception to
this is the output (switch) pin, which should
not have large areas of copper.) Large
moving. Furthermore, some of these
components such as the catch diode will
add heat to the PC board and the heat can
vary as the input voltage changes. For the
inductor, depending on the physical size,
type of core material and the DC resistance,
it could either act as a heat sink taking heat
away from the board, or it could add heat to
the board.
areas of copper provide the best transfer of
heat (lower thermal resistance) to the
surrounding air, and moving air lowers the
thermal resistance even further.
Package thermal resistance and junction
temperature rise numbers are all
approximate, and there are many factors
that will affect these numbers. Some of
these factors include board size, shape,
thickness, position, location, and even
board temperature. Other factors are,
trace width, total printed circuit copper area,
copper thickness, single or double-sided,
multilayer board and the amount of solder
on the board. The effectiveness of the PC
board to dissipate heat also depends on
the size, quantity and spacing of other
components on the board, as well as
whether the surrounding air is still or
YB1696 MRev.1.1 www.yobon.com.tw 10
Package Information
YB1696
150KHz, 3A PWM Buck Switching Regulator
TO263-5L
E
F
L2
D
L
A
C2
e
B
Symbol
A 4.38 4.78 0.172 0.188
B 0.72 0.92 0.028 0.036
C 0.36 0.41 0.014 0.016
C2 1.18 1.38 0.046 0.055
D 8.23 8.63 0.324 0.340
E 9.96 10.36 0.392 0.407
e 1.60 1.80 0.062 0.071
F 6.80 7.20 0.267 0.283
L 15.14 15.74 0.596 0.620
L1 2.28 2.79 0.089 0.110
L2 1.40 1.80 0.055 0.071
Dimensions In Millimeters Dimensions In Inches
Min. Max. Min. Max.
C
L1
YB1696 MRev.1.1 www.yobon.com.tw 11
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