ZTP7192Y
2A, 18V, 500KHz, Synchronous Step-Down DC/DC Converter
FEATURES
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DESCRIPTION
4.7V to 18V input voltage
Output adjustable from 0.6V to 15V
Output current up to 2A
Integrated 140mΩ/90mΩ power MOSFET switches
Shutdown current 3μA typical
Efficiency up to 95%
Fixed frequency 500KHz
Internal soft start
Over current protection and Hiccup
Over temperature protection
RoHS Compliant and 100% Lead (Pb) Free
The ZTP7192Y is a high-frequency, synchronous,
rectified, step-down, switch-mode converter with
internal power MOSFETs. It offers a very compact
solution to achieve a 2A continuous output current over
a wide input supply range, with excellent load and line
regulation. The ZTP7192Y has synchronous-mode
operation for higher efficiency over the output
current-load range.
Current-mode operation provides fast transient
response and eases loop stabilization.
Protection features include over-current protection and
thermal shutdown.
The ZTP7192Y requires a minimal number of readily
available, standard external components and is available
in space-saving TSOT23-6L package.
APPLICATIONS
Distributed power systems
Networking systems
● FPGA, DSP, ASIC power supplies
● Notebook computers
● Green electronics or appliance
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Pins Configuration
Top View
TSOT23-6L
ORDERING INFORMATION
PART
PACKAGE
RoHS
Ship, Quantity
ZTP7192Y
TSOT23-6L
Yes
Tape and Reel
BOOT 1
6 SW
GND 2
5 IN
FB 3
4 EN
Typical Application Circuit
Input
C1
10μF/25V
Ceramic
R4
100k
R5
4
C7
0.1μF
5
IN
EN
C5 100nF
1
BOOT
SW 6
ZTP7192Y
L1
4.7μH
Output
3.3V/2A
R1 20kΩ
FB 3
GND
2
R2
4.45kΩ
C2
10μF/6.3V
Ceramic x 2
Note: R5 and C7 are optional.
Details please see the DVT report.
DS-11; Apr. 30, 2014
Copyright © ZillTek Technology Corp.
-1-
4F-3, No.5, Technology Rd., Science-Based
Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com
ZTP7192Y
Absolute Maximum Ratings
Recommended Operating Conditions
Supply Voltage VIN ……...…………...…….…………. 4.7V to 18V
Output Voltage VOUT ……...…………...…….….. 0.6V to VIN–3V
Operating Temperature Range ……...…… –40°C to +125°C
Supply Voltage VIN ……………………………….... –0.3V to +19V
Switch Node VSW ………………………………. –0.3V to VIN+0.3V
Boost VBOOT …………………………………… VSW–0.3V to VSW+6V
All Other Pins …………………………………………… –0.3V to +6V
Power Dissipation @25℃…………………………………… 1.2W
Junction Temperature ………………………………………. +150°C
Lead Temperature …………………………………………….. +260°C
Storage Temperature Range …………....... –65°C to +150°C
ESD, HBM ………………………………………………………………. 2KV
ESD, MM ……………………………………………………………… 200V
Package Thermal Characteristics
TSOT23-6L:
Thermal Resistance, θJA ………………………………… 100°C/W
Thermal Resistance, θJC ……………………………………. 55°C/W
Pins Description
TSOT
23-6L
1
CAUTION: Stresses above those listed in “Absolute
Maximum Ratings” may cause permanent damage to
the device. This is a stress only rating and operation of
the device at these or any other conditions above those
indicated in the operational sections of this specification
is not implied.
Electro-Static Discharge Sensitivity
Symbol
Description
BOOT
High-side gate drive boost input.
2
GND
Ground.
3
FB
Feedback input.
4
EN
Enable input.
5
IN
Power input.
6
SW
Power switching output.
This integrated circuit can be damaged by ESD.
It is recommended that all integrated circuits
be handled with proper precautions. Failure
to observe proper handling and installation procedures
can cause damage. ESD damage can range from subtle
performance degradation to complete device failure.
Functional Block Diagram
OVP
+
_
RAMP
Oscillator
Fosc1 or
Fosc2
CLK
0.66V
FB 5
+
_
Current Sense
Amplifier +
Σ
2 IN
_
5V
0.3V
500K
Soft
Start
0.6V
1 BOOT
1.2pF
47pF
20K
−
+
+
Error
Amplifier
M1
S Q
+
_
Current
Comparator
3 SW
R Q
M2
4 GND
OVP
EN
IN 3.3V, Load=2A)
Shut Down (12V => 3.3V, Load=2A)
Output Ripple (12V => 3.3V, Load=2A)
Output Ripple (12V => 3.3V, Load=1A)
Output Ripple (12V => 3.3V, Load=0A)
Dynamic Load (Iload=0.2A_2A Vout=3.3V)
Short Circuit Protection
Efficiency
DS-11; Apr. 30, 2014
Copyright © ZillTek Technology Corp.
-4-
4F-3, No.5, Technology Rd., Science-Based
Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com
ZTP7192Y
APPLICATION INFORMATION
EN: Enable Input. EN is a digital input that turns the
regulator on or off. Drive EN high to turn on the
regulator, drive it low to turn it off. Pull up with 100kΩ
resistor for automatic startup.
Overview
The ZTP7192Y is a synchronous rectified, current-mode,
step-down regulator. It regulates input voltages from
4.7V to 18V down to an output voltage as low as 0.6V,
and supplies up to 2A of load current.
The ZTP7192Y uses current-mode control to regulate
the output voltage. The output voltage is measured at
FB through a resistive voltage divider and amplified
through the internal transconductance error amplifier.
The converter uses internal N-Channel MOSFET switches
to step-down the input voltage to the regulated output
voltage. Since the high side MOSFET requires a gate
voltage greater than the input voltage, a boost capacitor
connected between SW and BOOT is needed to drive
the high side gate. The boost capacitor is charged from
the internal 5V rail when SW is low.
When the ZTP7192Y FB pin exceeds 10% of the nominal
regulation voltage of 0.6V, the over voltage comparator
is tripped, forcing the high-side switch off.
Setting the Output Voltage
The external resistor divider sets the output voltage. The
feedback resistor R1 also sets the feedback-loop
bandwidth through the internal compensation capacitor
(see the Typical Application circuit). Choose R1 around
10kΩ, and R2 by:
R2 = R1 / (VOUT/0.6V – 1)
Use a network below for when VOUT is low.
FB
RT
R1
VOUT
R2
Figure 1: Feedback Network.
Table 1 lists the recommended resistors value for
common output voltages.(RT=0)
Pins Description
VOUT (V)
1.05
1.2
1.8
2.5
3.3
5
BOOT: High-Side Gate Drive Boost Input. BOOT supplies
the drive for the high-side N-Channel MOSFET switch.
Connect a 0.1μF or greater capacitor from SW to BOOT
to power the high side switch.
IN: Power Input. IN supplies the power to the IC, as well
as the step-down converter switches. Drive IN with a
4.7V to 18V power source. Bypass IN to GND with a
suitably large capacitor to eliminate noise on the input
to the IC.
Rt is used to set control loop’s bandwidth, which is
proportional to the relation by R1, R2, RT:
1/[(Rt+20k)*(1+R1/R2)+R1]
So Increase RT & Decrease R1&R2 value(keeping R1/R2
ratio), the bandwidth can be kept the same(the relation
value need to be the same)
Inductor
GND: Ground.
The inductor is required to supply constant current to
the output load while being driven by the switched
input voltage. A larger value inductor will result in less
ripple current that will result in lower output ripple
voltage. However, the larger value inductor will have a
larger physical size, higher series resistance, and/or
FB: Feedback Input. FB senses the output voltage to
regulate that voltage. Drive FB with a resistive voltage
divider from the output voltage. The feedback threshold
is 0.6V.
Copyright © ZillTek Technology Corp.
R2 (KΩ)
126.7(1%)
90(1%)
35(1%)
14.7(1%)
4.4(1%)
5.6(1%)
Table 1: Resistor selection for common output voltages.
SW: Power Switching Output. SW is the switching node
that supplies power to the output. Connect the output
LC filter from SW to the output load. Note that a
capacitor is required from SW to BOOT to power the
high-side switch.
DS-11; Apr. 30, 2014
R1 (KΩ)
95(1%)
90(1%)
70(1%)
46.7(1%)
20(1%)
41.4(1%)
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Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com
ZTP7192Y
lower saturation current. A good rule for determining
the inductance to use is to allow the peak-to-peak ripple
current in the inductor to be approximately 30% of the
maximum switch current limit. Also, make sure that the
peak inductor current is below the maximum switch
current limit. The inductance value can be calculated by:
rating. The RMS current in the input capacitor can be
estimated by:
IC1 = ILOAD × [ (VOUT/VIN) × (1 − VOUT/VIN) ]
L = [ VOUT / (fS × ΔIL) ] × (1 − VOUT/VIN)
Where VOUT is the output voltage, VIN is the input voltage,
fS is the switching frequency, and ΔIL is the peak-to-peak
inductor ripple current.
Choose an inductor that will not saturate under the
maximum inductor peak current. The peak inductor
current can be calculated by:
ILP = ILOAD + [ VOUT / (2 × fS × L) ] × (1 − VOUT/VIN)
Where ILOAD is the load current.
The choice of which style inductor to use mainly
depends on the price vs. size requirements and any EMI
requirements.
1/2
The worst-case condition occurs at VIN = 2VOUT, where IC1
= ILOAD/2. For simplification, choose the input capacitor
whose RMS current rating greater than half of the
maximum load current.
The input capacitor can be electrolytic, tantalum or
ceramic. When using electrolytic or tantalum capacitors,
a small, high quality ceramic capacitor, i.e. 0.1μF, should
be placed as close to the IC as possible. When using
ceramic capacitors, make sure that they have enough
capacitance to provide sufficient charge to prevent
excessive voltage ripple at input. The input voltage
ripple for low ESR capacitors can be estimated by:
ΔVIN = [ ILOAD/(C1 × fS) ] × (VOUT/VIN) × (1 − VOUT/VIN)
Where C1 is the input capacitance value.
Output Capacitor
Optional Schottky Diode
The output capacitor is required to maintain the DC
output voltage. Ceramic, tantalum, or low ESR
electrolytic capacitors are recommended. Low ESR
capacitors are preferred to keep the output voltage
ripple low. The output voltage ripple can be estimated
by:
During the transition between high-side switch and
low-side switch, the body diode of the low-side power
MOSFET conducts the inductor current. The forward
voltage of this body diode is high. An optional Schottky
diode may be paralleled between the SW pin and GND
pin to improve overall efficiency. Table 2 lists example
Schottky diodes and their Manufacturers.
Part
Number
B130
SK13
MBRS130
Voltage and
Current Rating
30V, 1A
30V, 1A
30V, 1A
ΔVOUT = [ VOUT/(fS × L) ] × (1 − VOUT/VIN)
× [ RESR + 1 / (8 × fS × C2) ]
Where C2 is the output capacitance value and RESR is the
equivalent series resistance (ESR) value of the output
capacitor.
In the case of ceramic capacitors, the impedance at the
switching frequency is dominated by the capacitance.
The output voltage ripple is mainly caused by the
capacitance. For simplification, the output voltage ripple
can be estimated by:
Vendor
Diodes Inc.
Diodes Inc.
International Rectifier
Table 2: Diode selection guide.
Input Capacitor
2
ΔVOUT = [ VOUT/(8 × fS × L × C2) ] × (1 − VOUT/VIN)
In the case of tantalum or electrolytic capacitors, the
ESR dominates the impedance at the switching
frequency. For simplification, the output ripple can be
approximated to:
The input current to the step-down converter is
discontinuous, therefore a capacitor is required to
supply the AC current to the step-down converter while
maintaining the DC input voltage. Use low ESR
capacitors for the best performance. Ceramic capacitors
are preferred, but tantalum or low-ESR electrolytic
capacitors may also suffice. Choose X5R or X7R
dielectrics when using ceramic capacitors.
Since the input capacitor (C1) absorbs the input
switching current it requires an adequate ripple current
DS-11; Apr. 30, 2014
Copyright © ZillTek Technology Corp.
ΔVOUT = [ VOUT/(fS × L) ] × (1 − VOUT/VIN) × RESR
The characteristics of the output capacitor also affect
the stability of the regulation system. The ZTP7192Y can
be optimized for a wide range of capacitance and ESR
values.
-6-
4F-3, No.5, Technology Rd., Science-Based
Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com
ZTP7192Y
Figure 3: Add a Schottky diode to promote efficiency
when VIN ≤ 6V.
External Bootstrap Diode
An external bootstrap diode may enhance the efficiency
of the regulator, the applicable conditions of external
BOOT diode are:
● VOUT = 5V or 3.3V; and
● Duty cycle is high: D = VOUT/VIN > 65%
In these cases, an external BOOT diode is recommended
from the output of the voltage regulator to BOOT pin, as
shown in Figure 2.
PCB Layout Guide
PCB layout is very important to achieve stable operation.
Please follow the guidelines below.
1) Keep the path of switching current short and
minimize the loop area formed by Input capacitor,
high-side MOSFET and low-side MOSFET.
2) Bypass ceramic capacitors are suggested to be put
close to the VIN Pin.
3) Ensure all feedback connections are short and direct.
Place the feedback resistors and compensation
components as close to the chip as possible.
4) Rout SW away from sensitive analog areas such as
FB.
5) Connect IN, SW, and especially GND respectively to a
large copper area to cool the chip to improve thermal
performance and long-term reliability.
External BOOT
Diode IN4148
BOOT
CBS
0.1~1μF
ZTP7192Y
SW
L
COUT
+
5V or
3.3V
Figure 2: Add optional external bootstrap diode to
enhance efficiency.
The recommended external BOOT diode is IN4148, and
the BOOT capacitor is 0.1 ~ 1μF.
BOM of ZTP7192Y
Please refer to the Typical Application Circuit.
When VIN ≤ 6V, for the purpose of promote the
efficiency, it can add an external Schottky diode
between IN and BOOT pins, as shown in Figure 3.
Schottky
(B0520LW)
5V
to 6V
Item
1
2
3
4
BOOT
VOUT
IN ZTP7192Y SW
Reference
C1
C5
C7
R4
Part
10μF
100nF
0.1μF
100K
Table 3: BOM selection table I.
GND
Vout = 5.0V
Vout = 3.3V
Vout = 2.5V
Vout = 1.8V
Vout = 1.2V
Vout = 1.05V
L1
6.8μH
4.7μH
3.3μH
2.2μH
2.2μH
2.2μH
R1
41.4K
20K
46.7K
70K
90K
95K
R2
5.6K
4.4K
14.7K
35K
90K
126K
C2
10μF×2
10μF×2
10μF×2
10μF×2
10μF×2
10μF×2
Table 4: BOM selection table II.
DS-11; Apr. 30, 2014
Copyright © ZillTek Technology Corp.
-7-
4F-3, No.5, Technology Rd., Science-Based
Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com
ZTP7192Y
PACKAGE DIMENSION
TSOT23-6L
D
C
B
e
b
A
H
A1
L
Symbol
A
A1
B
b
C
D
e
H
L
Dimensions in mm
Min
Max
0.700
0.900
0.000
0.100
1.600
1.700
0.350
0.500
2.650
2.950
2.820
3.020
0.950 BSC
0.080
0.200
0.300
0.600
DS-11; Apr. 30, 2014
Copyright © ZillTek Technology Corp.
Dimensions in Inch
Min
Max
0.028
0.035
0.000
0.004
0.063
0.067
0.014
0.020
0.104
0.116
0.111
0.119
0.037 BSC
0.003
0.008
0.012
0.024
-8-
4F-3, No.5, Technology Rd., Science-Based
Industrial Park, Hsinchu 30078, Taiwan
Tel: (886) 3577 7509; Fax: (886) 3577 7390
Email: sales@zilltek.com