Astec ATH18K12 18-a, 12-v input non-isolated wide-output adjust power module Datasheet

ATH18K12 Series —12-V Input
18-A, 12-V Input Non-Isolated
Wide-Output Adjust Power Module
REVISION 00 (30SEP2003)
Features
NOMINAL SIZE =
1.5 in x 0.87 in
(38,1 mm x 22,1 mm)
Description
The ATH18K12 series of non-isolated
power modules offers OEM designers a
combination of high performance, small
footprint, and industry leading features.
As part of a new class of power modules,
these products provide designers with the
flexibility to power the most complex
multi-processor digital systems using
off-the-shelf catalog parts.
The series employs double-sided surface
mount construction and provides highperformance step-down power conversion
for up to 18 A of output current from a
12-V input bus voltage. The output voltage of the ATH18K12 can be set to any
value over the range, 1.2 V to 5.5 V, using
a single resistor.
• Up to 18 A Output Current
• 12-V Input Voltage
• Wide-Output Voltage Adjust
(1.2 V to 5.5 V)
• Efficiencies up to 95 %
• 195 W/in³ Power Density
• On/Off Inhibit
• Output Voltage Sense
• Margin Up/Down Controls
• Under-Voltage Lockout
• Auto-Track™ Sequencing
• Output Over-Current Protection
(Non-Latching, Auto-Reset)
• Over-Temperature Protection
• Surface Mountable
• Operating Temp: –40 to +85 °C
• DSP Compatible Output Voltages
• IPC Lead Free 2
• Point-of-Load Alliance (POLA)
Compatible
Pin Configuration
This series includes Auto-Track™.
Auto-Track™ simplifies the task of supply
voltage sequencing in a power system by
enabling modules to track each other, or
any external voltage, during power up and
power down.
Other operating features include an
on/off inhibit, output voltage adjust (trim),
and margin up/down controls. To ensure
tight load regulation, an output voltage
sense is also provided. A non-latching
over-current trip and over-temperature
shutdown provides load fault protection.
Target applications include complex
multi-voltage, multi-processor systems
that incorporate the industry’s high-speed
DSPs, micro-processors and bus drivers.
Pin
1
2
3
4
5
6
7
8
9
10
Function
GND
Vin
Inhibit *
Vo Adjust
Vo Sense
Vout
GND
Track
Margin Down *
Margin Up *
* Denotes negative logic:
Open
= Normal operation
Ground = Function active
™
Track
Auto- ncing
e
Sequ
Standard Application
Rset = Resistor to set the desired output
voltage (see spec. table for values).
Cin = Required electrolytic 560 µF
Cout = Optional 330 µF electrolytic
Track
Margin Down
Margin Up
10
9
8
1
7
ATH18K12-9S
PTH12020W
(Top View)
VIN
2
VOUT
6
3
4
5
Vo Sense
Inhibit
RSET (Required)
0.1 W, 1 %
+
GND
North America (USA): 1-888-41-ASTEC
+
CIN
560 µF
(Required)
COUT
330 µF
(Optional)
L
O
A
D
GND
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
ATH18K12 Series—12-V Input
18-A, 12-V Input Non-Isolated
Wide-Output Adjust Power Module
REVISION 00 (30SEP2003)
Ordering Information
Input Voltage
10.8V to 13.2V
Options:
“-J”
“-SJ”
“-S”
-
Output Voltage
1.2V1 to 5.5V
Output Current
18A
Model Number
ATH18K12-9(S)(J)
Through-hole Termination, Tray Packaging
SMT Termination, Tray Packaging
SMT Termination, T&R Packaging
Notes:
1
Preset output voltage is 1.2V; externally adjustable to 5.5V
Pin Descriptions
Vin: The positive input voltage power node to the module, which is referenced to common GND.
Vout: The regulated positive power output with respect
to the GND node.
GND: This is the common ground connection for the
Vin and Vout power connections. It is also the 0 VDC
reference for the control inputs.
Inhibit: The Inhibit pin is an open-collector/drain negative
logic input that is referenced to GND. Applying a lowlevel ground signal to this input disables the module’s
o utput and turns o ff the o utput vo ltage. When the Inhibit
control is active, the input current drawn by the regulator is significantly reduced. If the Inhibit pin is left
open-circuit, the module will produce an output whenever a valid input source is applied.
Vo Adjust: A 0.1 W, 1 % tolerance (or better) resistor
must be connected directly between this pin and pin 7
(GND) pin to set the output voltage to the desired value.
The set point range for the output voltage is from 1.2 V
to 5.5 V. The resistor required for a given output voltage
may be calculated from the following formula. If left
open circuit, the module output will default to its lowest
output voltage value. For further information on output
voltage adjustment consult the related application note.
R set
0.8 V
= 10 k ·
Vout – 1.2 V
– 1.82 k
The specification table gives the preferred resistor values
for a number of standard output voltages.
Vo Sense: The sense input allows the regulation circuit to
compensate for voltage drop between the module and
the load. For optimal voltage accuracy Vo Sense should
be connected to Vout. It can also be left disconnected.
Track: This is an analog control input that enables the
output voltage to follow an external voltage. This pin
becomes active typically 20 ms after the input voltage
has been applied, and allows direct control of the output
voltage from 0 V up to the nominal set-point voltage.
Within this range the output will follow the voltage at
the Track pin on a volt-for-volt basis. When the control
voltage is raised above this range, the module regulates
at its set-point voltage. The feature allows the output
voltage to rise simultaneously with other modules powered from the same input bus. If unused, the input may
b e le ft unc o nnec ted. Note: Due to the under-voltage lockout
feature, the output of the module cannot follow its own input
voltage during power up. For more information, consult the
related application note.
Margin Down: When this input is asserted to GND, the
output voltage is decreased by 5% from the nominal. The
input requires an open-collector (open-drain) interface.
It is not TTL compatible. A lower percent change can
be accomodated with a series resistor. For further information, consult the related application note.
Margin Up: When this input is asserted to GND, the
output voltage is increased by 5%. The input requires an
open-collector (open-drain) interface. It is not TTL
compatible. The percent change can be reduced with a
series resistor. For further information, consult the
related application note.
** Auto-Track is a trademark of Texas Instruments, Inc.
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
ATH18K12 Series—12-V Input
18-A, 12-V Input Non-Isolated
Wide-Output Adjust Power Module
REVISION 00 (30SEP2003)
Environmental & Absolute Maximum Ratings
Characteristics
Symbols
Track Input Voltage
Operating Temperature Range
Solder Reflow Temperature
Storage Temperature
Mechanical Shock
V track
Ta
T reflow
Ts
Mechanical Vibration
Weight
Flammability
—
—
(Voltages are with respect to GND)
Conditions
Over Vin Range
Surface temperature of module body or pins
—
Per Mil-STD-883D, Method 2002.3
1 msec, ½ Sine, mounted
Mil-STD-883D, Method 2007.2
20-2000 Hz
Min
Typ
–0.2
–40
—
—
–40
—
Max
Units
—
85
215 (i)
125
V
°C
°C
°C
500
—
G’s
—
20
—
G’s
—
7
—
grams
V in
Meets UL 94V-O
Notes: (i) During reflow of SMD package version do not elevate peak temperature of the module, pins or internal components above the stated maximum. For
further guidance refer to the application note, “Reflow Soldering Requirements for Plug-in Power Surface Mount Products.”
Specifications
(Unless otherwise stated, Ta =25 °C, Vin =12 V, Vout =3.3 V, Cin =560 µF, Cout =0 µF, and Io =Iomax)
PTH12020W
Typ
Characteristics
Symbols
Conditions
Min
Max
Units
Output Current
Io
V in
0
0
10.8
—
—
—
—
—
—
—
—
±0.5
±5
±5
18 (1)
18 (1)
13.2
±2 (2)
—
—
—
A
Input Voltage Range
Set-Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Variation
60 °C, 200 LFM airflow
25 °C, natural convection
Over Io range
—
—
±3
Efficiency
η
—
—
—
—
—
—
—
—
—
—
95.0
93.5
92.2
90.8
90.0
88.5
86.5
32
1
30
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
5
—
8.8
70
130
±5
– 8 (3)
—
—
9.7
9.2
—
—
—
—
–0.13
—
10.4
—
Pin to GND
Inhibit (pin 3) to GND, Track (pin 8) open
Over Vin and Io ranges
Vin –0.5
–0.2
—
—
260
560 (5)
0
—
—
–0.24
5
320
—
330 (6)
Open (4)
0.5
—
—
380
—
10,000
Per Bellcore TR-332
50 % stress, Ta =40 °C, ground benign
5.3
—
—
Vo tol
∆Regtemp
∆Regline
∆Regload
∆Regtot
Vo Ripple (pk-pk)
Vr
Over-Current Threshold
Transient Response
Io trip
Margin Up/Down Adjust
Margin Input Current (pins 9 /10)
Track Input Current (pin 8)
Track Slew Rate Capability
Under-Voltage Lockout
ttr
∆Vtr
∆Vo margin
IIL margin
IIL track
dVtrack/dt
UVLO
Inhibit Control (pin3)
Input High Voltage
Input Low Voltage
Input Low Current
VIH
VIL
IIL inhibit
Input Standby Current
Switching Frequency
External Input Capacitance
External Output Capacitance
Reliability
Iin inh
ƒs
Cin
Cout
MTBF
–40 °C <Ta < +85 °C
Over Vin range
Over Io range
Includes set-point, line, load,
–40 °C ≤ Ta ≤ +85 °C
Io =10 A
RSET = 280 Ω Vo = 5.0 V
RSET = 2.0 kΩ Vo = 3.3 V
RSET = 4.32 kΩ Vo = 2.5 V
RSET = 8.06 kΩ Vo = 2.0 V
RSET = 11.5 kΩ Vo = 1.8 V
RSET = 24.3 kΩ Vo = 1.5 V
RSET = open cct.Vo = 1.2 V
20 MHz bandwidth
Vo ≤2.5 V
Vo >2.5 V
Reset, followed by auto-recovery
1 A/µs load step, 50 to 100 % Iomax,
Cout =330 µF
Recovery Time
Vo over/undershoot
Pin to GND
Pin to GND
Vtrack – Vo ≤ 50 mV and Vtrack < Vo(nom)
Vin increasing
Vin decreasing
Referenced to GND
(2)
V
%Vo
% Vo
mV
mV
%Vo
%
mVpp
% Vo
A
(4)
µSec
mV
%
µA
mA
V/ms
V
V
mA
mA
kHz
µF
µF
106 Hrs
Notes: (1) See SOA curves or consult factory for appropriate derating.
(2) The set-point voltage tolerance is affected by the tolerance and stability of RSET. The stated limit is unconditionally met if RSET has a tolerance of 1 %,
with 200 ppm/°C or better temperature stability.
(3) A small low-leakage (<100 nA) MOSFET is recommended to control this pin. The open-circuit voltage is less than 1 Vdc.
(4) This control pin has an internal pull-up to the input voltage Vin. If it is left open-circuit the module will operate when input power is applied. A small
low-leakage (<100 nA) MOSFET is recommended for control. For further information, consult the related application note.
(5) A 560 µF electrolytic input capacitor is required for proper operation. The capacitor must be rated for a minimum of 800 mA rms of ripple current.
(6) An external output capacitor is not required for basic operation. Adding 330 µF of distributed capacitance at the load will improve the transient response.
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
ATH18K12 Series—12-V Input
Typical Characteristics
18-A, 12-V Input Non-Isolated
Wide-Output Adjust Power Module
REVISION 00 (30SEP2003)
Safe Operating Area; Vin =12 V (See Note B)
Characteristic Data; Vin =12 V (See Note A)
Efficiency vs Load Current
Output Voltage =5 V
100
90
VOUT
5.0 V
3.3 V
2.5 V
2.0 V
1.8 V
1.5 V
1.2 V
80
70
60
80
Ambient Temperature (°C)
Efficiency - %
90
Airflow
70
400LFM
200LFM
100LFM
Nat conv
60
50
40
30
50
20
0
3
6
9
12
15
18
0
3
6
Iout - Amps
Output Ripple vs Load Current
12
15
18
Output Voltage =2.5 V
100
90
5.0 V
3.3 V
2.5 V
2.0 V
1.8 V
1.5 V
1.2 V
60
40
20
80
Ambient Temperature (°C)
VOUT
80
Ripple - mV
9
Iout (A)
Airflow
70
400LFM
200LFM
100LFM
Nat conv
60
50
40
30
0
20
0
3
6
9
12
15
18
0
3
6
Iout - Amps
Power Dissipation vs Load Current
12
15
18
Output Voltage =1.8 V
6
90
5.0 V
3.3 V
2.5 V
2.0 V
1.8 V
1.5 V
1.2 V
4
3
2
1
80
Ambient Temperature (°C)
VOUT
5
Pd - Watts
9
Iout (A)
Airflow
70
400LFM
200LFM
100LFM
Nat conv
60
50
40
30
0
20
0
5
10
15
0
3
Iout - Amps
6
9
12
15
18
Iout (A)
Note A: Characteristic data has been developed from actual products tested at 25°C. This data is considered typical data for the Converter.
Note B: SOA curves represent the conditions at which internal components are at or below the manufacturer’s maximum operating temperatures. Derating limits apply to
modules soldered directly to a 4 in. × 4 in. double-sided PCB with 1 oz. copper.
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH18K12 Series
Adjusting the Output Voltage of the ATH18K12
Wide-Output Adjust Power Module
The Vo Adjust control (pin 4) sets the output voltage of
the ATH18K12 product. The adjustment range is from 1.2 V
to 5.5 V. To adjust the output voltage above 1.2 V a single
external resistor, R set, must be connected directly between
the Vo Adjust and GND pins 1. Table 1-1 gives the preferred
value for the external resistor for a number of standard
voltages, along with the actual output voltage that this
resistance value provides.
For other output voltages the value of the required resistor
can either be calculated using the following formula, or
simply selected from the range of values given in Table 1-2.
Figure 1-1 shows the placement of the required resistor.
Rset
= 10 kΩ ·
0.8 V
Vout – 1.2 V
– 1.82 kΩ
Table 1-1; Preferred Values of R set for Standard Output Voltages
Vout (Standard)
Rset (Pref’d Value)
5V
3.3 V
2.5 V
2V
1.8 V
1.5 V
1.2 V
280 Ω
2 κΩ
4.32 κΩ
8.06 κΩ
11.5 κΩ
24.3 κΩ
Open
Vout (Actual)
5.009 V
3.294V
2.503 V
2.010V
1.801 V
1.506 V
1.200 V
Figure 1-1; Vo Adjust Resistor Placement
VO Sense [Note 3]
10
9
8
Table 1-2; Output Voltage Set-Point Resistor Values
Va Req’d
1.200
1.225
1.250
1.275
1.300
1.325
1.350
1.375
1.400
1.425
1.450
1.475
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
2.05
2.10
2.15
2.20
2.25
2.30
2.35
2.40
2.45
2.50
2.55
2.60
2.65
2.70
Rset
Open
318 κΩ
158 κΩ
105 κΩ
78.2 κΩ
62.2 κΩ
51.5 κΩ
43.9 κΩ
38.2 κΩ
33.7 κΩ
30.2 κΩ
27.3 κΩ
24.8 κΩ
21 κΩ
18.2 κΩ
16 κΩ
14.2 κΩ
12.7 κΩ
11.5 κΩ
10.5 κΩ
9.61 κΩ
8.85 κΩ
8.18 κΩ
7.59 κΩ
7.07 κΩ
6.6 κΩ
6.18 κΩ
5.8 κΩ
5.45 κΩ
5.14 κΩ
4.85 κΩ
4.85 κΩ
4.33 κΩ
4.11 κΩ
3.89 κΩ
3.7 κΩ
3.51 κΩ
Va Req’d
2.75
2.80
2.85
2.90
2.95
3.00
3.05
3.10
3.15
3.20
3.25
3.30
3.35
3.40
3.45
3.50
3.55
3.6
3.7
3.8
3.9
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
Rset
3.34 κΩ
3.18 κΩ
3.03 κΩ
2.89 κΩ
2.75 κΩ
2.62 κΩ
2.5 κΩ
2.39 κΩ
2.28 κΩ
2.18 κΩ
2.08 κΩ
1.99 κΩ
1.9 κΩ
1.82 κΩ
1.74 κΩ
1.66 κΩ
1.58 κΩ
1.51 κΩ
1.38 κΩ
1.26 κΩ
1.14 κΩ
1.04 κΩ
939 Ω
847 Ω
761 Ω
680 Ω
604 Ω
533 Ω
466 Ω
402 Ω
342 Ω
285 Ω
231 Ω
180 Ω
131 Ω
85 Ω
41 Ω
5
VO Sense
ATH18K12-9S
PTH12020W
GND
1
7
VOUT
6
VO Adj
4
RSET
0.1 W, 1 %
COUT
330µF
+
GND
VOUT
GND
North America (USA): 1-888-41-ASTEC
Notes:
1. Use a 0.1 W resistor. The tolerance should be 1 %, with
temperature stability of 100 ppm/°C (or better). Place
the resistor as close to the regulator as possible. Connect
the resistor directly between pins 4 and 7 using dedicated
PCB traces.
2. Never connect capacitors from Vo Adjust to either GND or
Vout. Any capacitance added to the Vo Adjust pin will affect
the stability of the regulator.
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH18K12 Series
ATH18K12: Capacitor Recommendations
Tantalum Capacitors
Tantalum type capacitors can be used for the output but
only the AVX TPS, Sprague 593D/594/595 or Kemet
T495/T510 series. These capacitors are recommended
over many other tantalum types due to their higher rated
surge, power dissipation, and ripple current capability.
As a caution the TAJ series by AVX is not recommended.
This series has considerably higher ESR, reduced power
dissipation, and lower ripple current capability. The TAJ
series is also less reliable than the AVX TPS series when
determining power dissipation capability. Tantalum or
Oscon® types are recommended for applications where
ambient temperatures fall below 0°C.
Input Capacitor
The recommended input capacitor(s) is determined by
the 560 µF minimum capacitance, and 800 mArms minimum ripple current rating.
Ripple current and <100 mΩ equivalent series resistance
(ESR) values are the major considerations, along with
temperature, when designing with different types of
capacitors. Tantalum capacitors have a recommended
minimum voltage rating of 2 × (max. DC voltage + AC
ripple). This is standard practice for tantalum capacitors to insure reliability. Tantalum capacitors are not
recommended on the input bus.
Ceramic Capacitors
Ceramic capacitors can be substituted for electrolytic
types on the output bus with the minimum capacitance
for reducd ripple and improved transient response.
Output Capacitors (Optional)
The recommended ESR of the output capacitor is equal to
or less than 150 mΩ. Electrolytic capacitors have marginal
ripple performance at frequencies greater than 400 kHz
but excellent low frequency transient response. Above the
ripple frequency, ceramic capacitors are necessary to improve the transient response and reduce any high frequency
noise components apparent during higher current excursions. Preferred low-ESR capacitor part numbers are
identified in Table 2-1.
Capacitor Table
Table 2-1 identifies the characteristics of capacitors from a
number of vendors with acceptable ESR and ripple current
(rms) ratings. The number of capacitors required at both the
input and output buses is identified for each capacitor type.
This is not an extensive capacitor list. Capacitors from other
vendors are available with comparable specifications. Those
listed are for guidance. The RMS ripple current rating and
ESR (at 100 kHz) are critical parameters necessary to insure
both optimum regulator performance and long-term reliability.
Table 2-1: Input/Output Capacitors
Capacitor Vendor/
Series
Capacitor Characteristics
Working
Voltage
Value (µF)
(ESR) Equivalent
Series Resistance
Quantity
105°C Maximum
Ripple
Current(Irms)
Physical
Size(mm)
Input
Bus
Optional
Output
Bus
Vendor Part Number
FK (Surface Mt)
25
25
25
35
V
V
V
V
330
560
1000
680
0.090
0.065
0.060
0.060
Ω
Ω
Ω
Ω
755 mA
1205 mA
1100mA
1100 mA
10×12.5
12.5×15
12.5×13.5
12.5×13.5
2
1
1
1
1
1
1
1
EEUFC1E331
EEUFC1E561S
EEVFK1E102Q
EEVFK1V681Q
United Chemi-Con
FX
LXZ Series
16 V
16 V
25V
330
330
680
0.018 Ω
0.090 Ω
0.068 Ω
4500 mA
760 mA
1050 mA
10×10.5
10×12.5
10×16
2
2
1
1
1
1
16FX330M
LXZ25VB331M10X12LL
LXZ16VB681M10X16LL
Nichicon
PM Series
25 V
25 V
35 V
560
680
560
0.060 Ω
0.055 Ω
0.048 Ω
1060 mA
1270 mA
1360 mA
12.5×15
16×15
16×15
1
1
1
1
1
1
UPM1E561MHH6
UPM1E681MHH6
UPM1V561MHH6
Os-con:
SP
SVP (Surface Mt)
16 V
16 V
270
330
0.018 Ω
0.016 Ω
>3500 mA
4700 mA
10×10.5
11×12
2
2
1
1
16SP270M
16SVP330M
AVX Tantalum
TPS (Surface Mt)
10 V
10 V
330
330
0.1 Ω
0.06 Ω
>2500 mA
>3000 mA
7.3L
×5.7W
×4.1H
N/R
N/R
(1)
1
1
TPSE337M010R0100 (Vo<5.1V)
TPSV337M010R0060 (Vo<5.1V)
Kemet Tantalum
T520/T495 Series
(Surface Mt)
10 V
10 V
330
220
0.040 Ω
0.07 Ω
1600 mA
>2000 mA
4.3W
×7.3L
×4.0H
N/R
N/R
(1)
(1)
1
1
520X337M010AS (Vo<5.1V)
T495X227M0100AS (Vo<5.1V)
Sprague Tantalum
594D Series
(Surface Mt)
10 V
330
0.045 Ω
2360 mA
7.2L
×6W
×4.1H
N/R
(1)
1
594D337X0010R2T (Vo<5.1V)
Panasonic
FC (Radial)
(1)
(1) N/R –Not recommended. The voltage rating does not meet the minimum operating limits.
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH Series of Wide-Output Adjust
Power Modules (12-V Input)
Features of the ATH Family of Non-Isolated
Wide Output Adjust Power Modules
This is a feature unique to the ATH family, and was
specifically designed to simplify the task of sequencing the
supply voltage in a power system. These and other features
are described in the following sections.
Point-of-Load Alliance
The ATH family of non-isolated, wide-output adjust
power modules from Texas Instruments are optimized
for applications that require a flexible, high performance
module that is small in size. These products are part of
the “Point-of-Load Alliance” (POLA), which ensures
compatible footprint, interoperability and true second
sourcing for customer design flexibility. The POLA is a
collaboration between Texas Instruments, Artesyn Technologies, and Astec Power to offer customers advanced
non-isolated modules that provide the same functionality
and form factor. Product series covered by the alliance
includes the ATH06 (6 A), ATH10 (10 A), ATH12/15
(12/15 A), ATH18/22 (18/22 A), and the ATH26/30 (26/
30 A).
From the basic, “Just Plug it In” functionality of the 6-A
modules, to the 30-A rated feature-rich ATH30 Series,
these products were designed to be very flexible, yet simple
to use. The features vary with each product. Table 3-1
provides a quick reference to the available features by
product and input bus voltage.
Power-Up Characteristics
When configured per their standard application all the
ATH products will produce a regulated output voltage following the application of a valid input source voltage. All
the modules include soft-start circuitry. This slows the initial
rate in which the output voltage can rise, thereby limiting
the amount of in-rush current that can be drawn from the
input source. The soft-start circuitry also introduces a short
time delay (typically 5 ms-10 ms) into the power-up
characteristic. This delay is from the point that a valid
input source is recognized, to the initial rise of the output
voltage. Figure 3-1 shows the power-up characteristic of
the 10-A output product (ATH10K12), operating from a
12-V input bus and configured for a 3.3-V output. The
waveforms were measured with a 5-A constant current
load. The initial rise in input current when the input
voltage first starts to rise is the charge current drawn by
the input capacitors.
Figure 3-1
PTHxx030
ATH26/30
6A
3.3 V / 5 V
10 A
12 V
10
8 AA
3.3 V / 5 V
15 A
12 V
12 A
3.3 V / 5 V
22 A
12 V
18 A
3.3 V / 5 V
30 A
12 V
26 A
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Thermal Shutdown
•
•
•
•
•
•
•
•
•
•
•
Pre-Bias Startup
6A
12 V
•
•
•
•
•
•
•
•
•
•
•
Output Sense
PTHxx020
ATH18/22
5V
•
•
•
•
•
•
•
•
•
•
•
Margin Up/Down
PTHxx010
ATH12/15
6A
Auto-Track™
PTHxx060
ATH10
I OUT
Over-Current
PTHxx050
ATH06
Input Bus
3.3 V
On/Off Inhibit
Series
Adjust (Trim)
Table 3-1; Operating Features by Series and Input Bus Voltage
Vo (2 V/Div)
Iin (2 A/Div)
HORIZ SCALE: 5 ms/Div
•
•
•
•
For simple point-of-use applications, the ATH06 (6A)
provides operating features such as an on/off inhibit,
output voltage trim, pre-bias startup (3.3/5-V input only), and
over-current protection. The ATH10 (10 A), and ATH12/
15 (12/15 A) include an output voltage sense, and margin
up/down controls. Then the higher output current,
ATH18/22 (18/22A) and ATH26/30 (26/30A) products incorporate over-temperature shutdown protection. All of the
products referenced in Table 3-1 include Auto-Track™.
North America (USA): 1-888-41-ASTEC
Vin (5 V/Div)
Over-Current Protection
For protection against load faults, all modules incorporate
output over-current protection. Applying a load that
exceeds the regulator’s over-current threshold will cause
the regulated output to shut down. Following shutdown, a
module will periodically attempt to recover by initiating
a soft-start power-up. This is described as a “hiccup” mode
of operation, whereby the module continues in a cycle of
successive shutdown and power up until the load fault is
removed. During this period, the average current flowing
into the fault is significantly reduced. Once the fault is
removed, the module automatically recovers and returns
to normal operation.
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Asia (HK): 852-2437-9662
Application Notes
ATH Series of Wide-Output Adjust
Power Modules (12-V Input)
Output On/Off Inhibit
Remote Sense
For applications requiring output voltage on/off control,
each series of the ATH family incorporates an output
Inhibit control pin. The inhibit feature can be used wherever there is a requirement for the output voltage from
the regulator to be turned off.
The ATH10 (10A), ATH12/15 (12/15A), ATH18/22 (18/
22A), and ATH26/30 (26/30A) products incorporate an
output voltage sense pin, Vo Sense. The Vo Sense pin should
be connected to Vout at the load circuit (see data sheet standard application). A remote sense improves the load
regulation performance of the module by allowing it to
compensate for any ‘IR’ voltage drop between itself and the
load. An IR drop is caused by the high output current
flowing through the small amount of pin and trace resistance. Use of the remote sense is optional. If not used,
the Vo Sense pin can be left open-circuit. An internal
low-value resistor (15-Ω or less) is connected between
the Vo Sense and Vout. This ensures the output voltage remains in regulation.
The power modules function normally when the Inhibit
pin is left open-circuit, providing a regulated output
whenever a valid source voltage is connected to Vin with
respect to GND.
Figure 3-2 shows the typical application of the inhibit
function. Note the discrete transistor (Q1). The Inhibit
input has its own internal pull-up to Vin potential (12 V).
The input is not compatible with TTL logic devices. An
open-collector (or open-drain) discrete transistor is recommended for control.
Turning Q1 on applies a low voltage to the Inhibit control
pin and disables the output of the module. If Q1 is then
turned off, the module will execute a soft-start power-up
sequence. A regulated output voltage is produced within
20 msec. Figure 3-3 shows the typical rise in both the
output voltage and input current, following the turn-off
of Q1. The turn off of Q1 corresponds to the rise in the
waveform, Q1 Vds. The waveforms were measured with
a 5-A constant current load.
Figure 3-2
With the sense pin connected, the difference between
the voltage measured directly between the Vout and GND
pins, and that measured from V o Sense to GND, is the
amount of IR drop being compensated by the regulator.
This should be limited to a maximum of 0.3 V.
Note: The remote sense feature is not designed to compensate
for the forward drop of non-linear or frequency dependent
components that may be placed in series with the converter
output. Examples include OR-ing diodes, filter inductors,
ferrite beads, and fuses. When these components are enclosed
by the remote sense connection they are effectively placed
inside the regulation control loop, which can adversely affect
the stability of the regulator.
Vo Sense
Over-Temperature Protection (OTP)
VIN
2
8
5
1
7
4
+
Q1
BSS138
1 =Inhibit
GND
VOUT
6
PTH12060W
ATH10K12
3
CIN
560 µF
9
RSET
2.0kΩ
1%
0.1 W
COUT
330 µF
+
10
L
O
A
D
GND
Figure 3-3
Q1Vds (5 V/Div)
Vo (2 V/Div)
The ATH18/22 (18/22A) and ATH26/30 (26/30A) series of
products have over-temperature protection. These products have an on-board temperature sensor that protects
the module’s internal circuitry against excessively high
temperatures. A rise in the internal temperature may be
the result of a drop in airflow, or a high ambient temperature. If the internal temperature exceeds the OTP
threshold, the module’s Inhibit control is automatically
pulled low. This turns the output off. The output voltage
will drop as the external output capacitors are discharged
by the load circuit. The recovery is automatic, and begins with a soft-start power up. It occurs when the the
sensed temperature decreases by about 10 °C below the
trip point.
Note: The over-temperature protection is a last resort mechanism to prevent thermal stress to the regulator. Operation at
or close to the thermal shutdown temperature is not recommended and will reduce the long-term reliability of the module.
Always operate the regulator within the specified Safe Operating
Area (SOA) limits for the worst-case conditions of ambient
temperature and airflow.
Iin (2 A/Div)
HORIZ SCALE: 10 ms/Div
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH Series of Wide-Output Adjust
Power Modules (12-V Input)
Auto-Track™Function
The Auto-Track™ function is unique to the ATH family,
and is available with the all “Point-of-Load Alliance”
(POLA) products. Auto-Track™ was designed to simplify
the amount of circuitry required to make the output
voltage from each module power up and power down in
sequence. The sequencing of two or more supply voltages
during power up is a common requirement for complex
mixed-signal applications, that use dual-voltage VLSI ICs
such as DSPs, micro-processors, and ASICs.
How Auto-Track™ Works
Auto-Track™ works by forcing the module’s output voltage
to follow a voltage presented at the Track control pin. This
control range is limited to between 0 V and the module’s
set-point voltage. Once the track-pin voltage is raised
above the set-point voltage, the module’s output remains
at its set-point 1. As an example, if the Track pin of a 2.5-V
regulator is at 1 V, the regulated output will be 1 V. But
if the voltage at the Track pin rises to 3 V, the regulated
output will not go higher than 2.5 V.
When under track control, the regulated output from
the module follows the voltage at its Track pin on a voltfor-volt basis. By connecting the Track pin of a number
of these modules together, the output voltages will follow a common signal during power-up and power-down.
The control signal can be an externally generated master
ramp waveform, or the output voltage from another power
supply circuit 3. The Track control also incorporates an
internal RC charge circuit. This operates off the module’s
input voltage to produce a suitable rising waveform at
power up.
Typical Application
The basic implementation of Auto-Track™ allows for
simultaneous voltage sequencing of a number of AutoTrack™ compliant modules. Connecting the Track control
pins of two or more modules forces the Track control of
all modules to follow the same collective RC ramp waveform, and allows them to be controlled through a single
transistor or switch; Q1 in Figure 3-4.
To initiate a power-up sequence, it is recommended that
the Track control be first pulled to ground potential.
This should be done at or before input power is applied
to the modules, and then held for at least 10 ms thereafter. This brief period gives the modules time to complete
their internal soft-start initialization. Applying a logiclevel high signal to the circuit’s On/Off Control turns
Q1 on and applies a ground signal to the Track pins. After
completing their internal soft-start intialization, the output of all modules will remain at zero volts while Q1 is on.
10 ms after a valid input voltage has been applied to the
modules, Q1 may be turned off. This allows the track control voltage to automatically rise toward to the modules'
input voltage. During this period the output voltage of
each module will rise in unison with other modules, to its
respective set-point voltage.
Figure 3-5 shows the output voltage waveforms from the
circuit of Figure 3-4 after the On/Off Control is set from a
high to a low-level voltage. The waveforms, Vo1 and Vo2
represent the output voltages from the two power modules, U1 (3.3 V) and U2 (2.0 V) respectively. Vo1 and Vo2
are shown rising together to produce the desired simultaneous power-up characteristic.
The same circuit also provides a power-down sequence.
Power down is the reverse of power up, and is accomplished by lowering the track control voltage back to zero
volts. The important constraint is that a valid input voltage
must be maintained until the power down is complete. It
also requires that Q1 be turned off relatively slowly. This
is so that the Track control voltage does not fall faster than
Auto-Track's slew rate capability, which is 5 V/ms. The
components R1 and C1 in Figure 3-4 limit the rate at
which Q1 can pull down the Track control voltage. The
values of 100 k-ohm and 0.047 µF correlate to a decay
rate of about 0.6 V/ms.
The power-down sequence is initiated with a low-to-high
transition at the On/Off Control input to the circuit.
Figure 3-6 shows the power-down waveforms. As the
Track control voltage falls below the nominal set-point
voltage of each power module, then its output voltage
decays with all the other modules under Auto-Track™
control.
Notes on Use of Auto-Track™
1. The Track pin voltage must be allowed to rise above
the module’s set-point voltage before the module can
regulate at its adjusted set-point voltage.
2. The Auto-Track™ function will track almost any
voltage ramp during power up, and is compatible
with ramp speeds of up to 5 V/ms.
3. The absolute maximum voltage that may be applied
to the Track pin is Vin. The open-circuit voltage is
0.56 × Vin, or 7.5 VDC maximum.
4. The module will not follow a voltage at its Track control
input until it has completed its soft-start initialization.
This takes about 10 ms from the time that the module
has sensed that a valid voltage has been applied its input.
During this period, it is recommended that the Track
pin be held at ground potential.
5. Once its soft-start initialization is complete, the module
is capable of both sinking and sourcing current when
following the voltage at the Track pin.
6. The Auto-Track™ function can be disabled by
connecting the Track pin to the input voltage (Vin)
through a 1-kΩ resistor. When Auto-Track™ is
disabled, the output voltage will rise faster
following the application of input power.
**Auto-Track is a trademark of Texas Instruments, Inc.
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH Series of Wide-Output Adjust
Power Modules (12-V Input)
Figure 3-4; Sequenced Power Up & Power Down Using Auto-Track
U1
10
9
8
5
Track
Inhibit
+
CIN
ATH18K12
PTH12020W
VIN
VO
Vo1 =3.3V
6
GND
3
7
1
COUT
4
R2
2.0kΩ
+
2
+12V
C1
0.047µF
U2
9
8
5
Track
2
CIN
0V
Figure 3-5; Simultaneous Power Up with Auto-Track Control
+
R1
100k
10
Q1
BSS138
ATH12K12
PTH12010W
VIN
Inhibit
3
VO
Vo2 =2V
6
GND
1
7
4
R3
8k06
COUT
+
On/Off Control
1 = Power Down
0 = Power Up
Figure 3-6; Simultaneous Power Down with Auto-Track Control
Vo1 (1 V/Div)
Vo1 (1V/Div)
Vo2 (1 V/Div)
Vo2 (1 V/Div)
On/Off Control
(5 V/Div)
On/Off Control
(5 V/Div)
HORIZ SCALE: 5 ms/Div
HORIZ SCALE: 10 ms/Div
North America (USA): 1-888-41-ASTEC
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662
Application Notes
ATH Series of Wide-Output Adjust
Power Modules (12-V Input)
Margin Up/Down Controls
Notes:
The ATH10 (10A), ATH12/15 (12/15A), ATH18/22 (18/
22A), and ATH26/30 (26/30A) products incorporate Margin
Up and Margin Down control inputs. These controls allow
the output voltage to be momentarily adjusted 1, either up
or down, by a nominal 5 %. This provides a convenient
method for dynamically testing the operation of the load
circuit over its supply margin or range. It can also be used to
verify the function of supply voltage supervisors. The
±5 % change is applied to the adjusted output voltage, as set
by the external resistor, Rset at the Vo Adjust pin.
1. The Margin Up* and Margin Dn* controls were not
intended to be activated simultaneously. If they are
their affects on the output voltage may not completely
cancel, resulting in the possibility of a slightly higher
error in the output voltage set point.
The 5 % adjustment is made by pulling the appropriate
margin control input directly to the GND terminal 2.
A low-leakage open-drain device, such as an n-channel
MOSFET or p-channel JFET is recommended for this
purpose 3. Adjustments of less than 5 % can also be accommodated by adding series resistors to the control inputs
(See Figure 3-4). The value of the resistor can be selected
from Table 3-2, or calculated using the following formula.
2. The ground reference should be a direct connection to
the module GND at pin 7 (pin 1 for the ATH06).
This will produce a more accurate adjustment at the
load circuit terminals. The transistors Q1 and Q2 should
be located close to the regulator.
3. The Margin Up and Margin Dn control inputs are not
compatible with devices that source voltage. This includes
TTL logic. These are analog inputs and should only be
controlled with a true open-drain device (preferably
a discrete MOSFET transistor). The device selected
should have low off-state leakage current. Each input
sources 8 µA when grounded, and has an open-circuit
voltage of 0.8 V.
Up/Down Adjust Resistance Calculation
To reduce the margin adjustment to something less than
5 %, series resistors are required (See RD and RU in
Figure 3-7). For the same amount of adjustment, the
resistor value calculated for RU and RD will be the same.
The formulas is as follows.
RU or RD =
499
∆%
– 99.8
Table 3-2; Margin Up/Down Resistor Values
% Adjust
5
4
3
2
1
kΩ
Where ∆% = The desired amount of margin adjust in
percent.
RU / RD
0.0 kΩ
24.9 kΩ
66.5 kΩ
150.0 kΩ
397.0 kΩ
Figure 3-7; Margin Up/Down Application Schematic
10
9
8
1
7
ATH15T05
PTH05010W
(Top View)
VIN
0V
2
RD
4
MargUp
5
RU
RSET
0.1 W, 1 %
Cin
MargDn
+VOUT
6
3
+
+Vo
+
Cout
Q2
GND
North America (USA): 1-888-41-ASTEC
L
O
A
D
Q1
GND
Europe (UK): 44(1384)842-211
Asia (HK): 852-2437-9662