TI PT6521

PT6520 Series
8-A 5-V/3.3-V Input Adjustable ISR
with Short-Circuit protection
SLTS104A
(Revised 1/25/2002)
Features
•
•
•
•
•
•
•
•
•
8A Rated Output Current
Single Device: 3.3V/5V Input
High Efficiency (92% for PT6521)
Small Footprint (0.75 in², Suffix ‘P’)
Output On/Off Standby Control
Output Short-Circuit Protection
Adjustable Output Voltage
Soft Startup
16-pin Mount Option
(Suffixes L, M, Q, & F)
Ordering Information
Description
These power modules are a series of
high performance, 8-A rated, Integrated
Switching Regulators (ISRs), housed in a
low cost 14-Pin SIP (Single In-line Package). Operating from either a 3.3V or 5V
standard power bus, the PT6520 series
produces a high-output, low-voltage
power source for the industry’s latest
high-speed, microprocessors, ASICs, &
DSPs. This allows for the easy integration
of these new low-voltage ICs into existing
3.3V or 5V systems without re-designing
the power supply.
The PT6520 series features an output
On/Off standby pin and output shortcircuit protection.
†
†
†
†
†
PT6521¨
PT6522¨
PT6523¨
PT6525¨
PT6526¨
PT6527¨
=
=
=
=
=
=
3.3 Volts
1.5 Volts
2.5 Volts
2.1 Volts
1.8 Volts
1.2 Volts
Note:
Back surface of
product is electrically
conductive
PT6520
† 3.3V Input Bus Capable
PT Series Suffix (PT1234x )
Case/Pin
Configuration
Pin-Out Information
Order
Suffix
Package
Code *
P
D
E
M
L
Q
F
R
G
B
(EED)
(EEA)
(EEC)
(EEM)
(EEL)
(EEQ)
(EEF)
(EEE)
(EEG)
(EEK)
Vertical
Horizontal
SMD
Horizontal, 2-Pin Tab
SMD, 2-Pin Tab
Horizontal, 2-Pin Ext Tab
SMD, 2-Pin Ext Tab
Vertical, Side Tab
Horizontal, Side Tab
SMD, Side Tab
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
* Previously known as package styles 400/410.
(Reference the applicable package code drawing for the
dimensions and PC board layout)
Function
Remote Sense
Do Not Connect
STBY*
Vin
Vin
Vin
GND
GND
GND
GND
Vout
Vout
Vout
Vout Adjust
* For further information, see
application notes.
Standard Application
VoADJ
VoSENSE
14
VIN
4,5,6
+
1
PT6520
3
7–10
CIN
COM
For technical support and more information, see inside back cover or visit www.ti.com
VOUT
11,12,13
+
COUT
LOAD
COM
PT6520 Series
8-A 5-V/3.3-V Input Adjustable ISR
with Short-Circuit protection
Specifications
(Unless otherwise stated, Ta =25°C, Vin =5V, Cin =330µF, Cout =330µF, and Io =Iomax)
Characteristic
Symbol
Output Current
Input Voltage Range
Io
Vin
Set Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Voltage Variation
Vo tol
Regtemp
Regline
Regload
∆Votot
Efficiency
η
Conditions
Min
Over Vin range
Over Io Range
Vo =3.3V
Vo ≤2.5V
–40° ≤Ta ≤ +85°C, Io =Iomin
Over Vin range
Over Io range
Includes set-point, line, load,
–40° ≤Ta ≤ +85°C
Io =3.0A
Io =8.0A
Vo Ripple (pk-pk)
Transient Response
Short Circuit Threshold
Switching Frequency
Remote On/Off (Pin 1)
Input High Voltage
Input Low Voltage
Input Low Current
Vr
ttr
∆Vtr
Isc threshold
ƒs
VIH
VIL
IIL
Standby Input Current
External Output Capacitance
External Input Capacitance
Operating Temperature Range
Storage Temperature
Reliability
Iin standby
Cout
Cin
Ta
Ts
MTBF
Mechanical Shock
—
Mechanical Vibration
Mil-Std-883D, 20-2000Hz
Weight
—
Flammability
—
—
20MHz bandwidth
1A/µs load step, 50% to 100% Iomax
Vo over/undershoot
Over Vin and Io range
Referenced to –Vin (pin 7)
pins 3 & 7 connected
See application schematic
See application schematic
Over Vin range
—
Per Bellcore TR-332
50% stress, Ta =40°C, ground benign
Per Mil-Std-883D, method 2002.3,
1ms, half-sine, mounted to a fixture
Suffixes P, D, & E
Suffixes L & M
Suffixes P, D, & E
Suffixes R, G & B
Suffixes L & M
Suffixes Q & F
Materials meet UL 94V-0
Vo =3.3V
Vo =2.5V
Vo =2.1V
Vo =1.8V
Vo =1.5V
Vo =1.2V
Vo =3.3V
Vo =2.5V
Vo =2.1V
Vo =1.8V
Vo =1.5V
Vo =1.2V
PT6520 SERIES
Typ
Max
Units
0.1 (1)
4.5
3.1
—
—
—
—
—
—
—
±1
±0.5
±5
±5
8.0
5.5
5.5
±1.5
—
±10
±10
A
—
±2
±3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
300
92
88
85
82
80
75
89
85
82
78
75
71
35
50
±70
12
350
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
22.5
400
—
–0.1
—
—
330
330
-40
-40
—
—
–0.5
15
—
—
—
—
Open (2)
+0.4
–
25
5,000
—
+85 (3)
+125
mA
mA
µF
µF
°C
°C
6.3
—
—
106 Hrs
—
500
—
G’s
—
—
—
—
—
—
7.5
TBD (4)
12.5
16.5
15.25
22
—
—
—
—
—
—
G’s
VDC
%Vo
%Vo
mV
mV
%Vo
%
%
mVpp
µs
mV
A
kHz
V
grams
Notes: (1) The ISR will operate at no load with reduced specifications.
(2) The STBY* control (pin 3) has an internal pull-up and if it is left open circuit the module will operate when input power is applied. The open-circuit
voltage is typically 12.6V, and maybe as high as 15V. Refer to the application notes for other interface considerations.
(3) See Safe Operating Area curves or contact the factory for the appropriate derating.
(4) The tab pins on the 16-pin mount package types (suffixes L & M) must be soldered. For more information see the applicable package outline drawing.
Input/Output Capacitors: The PT6520 series requires a 330µF capacitor at both the input and output for proper operation in all applications. In addition, the input
capacitance (Cin) must be rated for a minimum of 1.2Arms ripple current rating. For transient or dynamic load applications, additional output capacitance (Cout) may be
necessary. The maximum allowable output capacitance is 5,000µF. For more information consult the related application note on capacitor recommendations.
For technical support and more information, see inside back cover or visit www.ti.com
Typical Characteristics
PT6520 Series
8-A 5-V/3.3-V Input Adjustable ISR
with Short-Circuit protection
Characteristic Data; Vin =5.0V
Characteristic Data; Vin =3.3V
(See Note A)
Efficiency vs Output Current
(See Note A)
Efficiency vs Output Current
100
100
90
90
Efficiency - %
80
3.3V
2.5V
1.8V
1.2V
70
60
Efficiency - %
VOUT
50
VOUT
80
2.5V
1.8V
1.2V
70
60
50
40
40
0
1
2
3
4
5
6
7
8
0
1
2
3
Iout (A)
Output Ripple vs Output Current
5
6
7
8
Output Ripple vs Output Current
40
40
35
35
30
30
VOUT
25
3.3V
2.5V
1.8V
1.2V
20
15
VOUT
Ripple - mV
Ripple - mV
4
Iout (A)
25
2.5V
1.8V
1.2V
20
15
10
10
5
5
0
0
0
1
2
3
4
5
6
7
0
8
1
2
3
Iout (A)
4
5
6
7
8
Iout (A)
Power Dissipation vs Output Current
Power Dissipation Output Current
5
5
4
4
1.2V
1.8V
2.5V
3.3V
3
2
VOUT
Pd - Watts
Pd - Watts
VOUT
3
1.2V
1.8V
2.5V
2
1
1
0
0
0
1
2
3
4
5
6
7
0
8
1
2
3
Safe Operating Area; Vin =5V (See Note B)
5
6
7
8
Safe Operating Area; 3.3V (See Note B)
90
90
80
Airflow
70
200LFM
120LFM
60LFM
Nat conv
60
50
40
30
Ambient Temperature (°C)
80
Ambient Temperature (°C)
4
Iout (A)
Iout (A)
70
Airflow
200LFM
120LFM
60LFM
Nat conv
60
50
40
30
20
20
0
1
2
3
4
5
6
7
8
Iout (A)
0
1
2
3
4
5
6
7
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
For technical support and more information, see inside back cover or visit www.ti.com
8
Application Notes
PT6520 Series
Using the Standby Function of the PT6520
Series of Integrated Switching Regulators
The PT6520 series of power modules are high efficiency
regulators that operate off either a 3.3V or 5V input
bus voltage. These regulators incorporate a Standby
function, which may be used in applications that require
power-up/shutdown sequencing, and wherever there is a
requirement for the output status of the module to be
controlled by external circuitry.
Figure 1
1
Vo(sense)
4,5,6
V in
STBY
+
3
C in
The standby function is provided by the STBY* control,
pin 3. If pin 3 is left open-circuit 1 the regulator operates
normally, and provides a regulated output when a valid
supply voltage is applied to Vin (pins 4–6) with respect
to GND (pins 7–10). If a low voltage 2 is then applied
to pin 3 the regulator output will be disabled and the
input current drawn by the ISR will be reduced to about
15mA 3. The standby control may also be used to hold-off
the regulator output during the period that input power is
applied.
Pin 3 is ideally controlled with an open-collector (or opendrain) discrete transistor (See Figure 1). The open-circuit
voltage is typcially 12.6V. Table 1 gives the circuit parameters for this control input.
Table 1 Standby Control Requirements (2, 3)
Parameter
Min
Typ
Input Low (V IL )
Istby (pin 3 =ground)
Vstby (open circuit)
–0.1V
Max
+0.4V
–0.5mA
12.6V
PT6520
Vin
GND
7,8,9,10
Vo
11,12,13
Vo
Vo(adj)
+
14
Cout
COM
COM
Inhibit
Q1
BSS138
Turn-On Time: In the circuit of Figure 1, turning Q1 on applies
a low voltage to the STBY control (pin 3) and disables the
regulator ouput. Correspondingly, turning Q1 off removes the
low-voltage signal and enables the output. Once enabled, the
output will typically experience a 10–15ms delay followed by a
predictable ramp-up of voltage. The regulator should provide a
fully regulated output voltage within 40ms. The waveform of
Figure 2 shows the output voltage and input current waveforms
of a PT6521 (3.3V) following the turn-off of Q1. The turn off
of Q1 corresponds to the rise in Vstby. The waveforms were
measured with a 5Vdc input voltage, and 4.5A resistive load.
15V
Notes:
1 The standby control input requires no external pull-up
resistor. The open-circuit voltage of the STBY* pin is
typically 12.6V.
Figure 2
Vo (1V/Div)
2. The standby control input is Not compatible with TTL or
other devices that incorporate a totem-pole output drive.
Use only a true open-collector device, preferably a discrete
bipolar transistor (or MOSFET). To ensure the regulator
output is disabled, the control pin must be pulled to less
than 0.4Vdc with a low-level 0.5mA sink to ground.
Iin (2A/Div)
Vstby (10V/Div)
3. When the regulator output is disabled the current drawn
from the input source is typically reduced to 15mA.
HORIZ SCALE: 5ms/Div
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT6520 Series
Adjusting the Output Voltage of the PT6520
Series of Integrated Switching Regulators
Figure 1
The output voltage of the PT6520 series of integrated
switching regulators (ISRs) may be adjusted higher or
lower than the factory trimmed pre-set voltage with the
addition of a single external resistor. 1 Table 1 gives the
allowable adjustment range for each model in the series as
Va (min) and Va (max).
1
Vo(sense)
4,5,6
Vin
PT6520
Vin
STBY
3
+
GND
7,8,9,10
Vout
11,12,13
14
(R1)
Adj Down
C in
Adjust Up: An increase in the output voltage is obtained
by adding a resistor R2, between pin 14 (Vo adjust) and
pins 7-10 (GND).
Vo
Vo(adj)
+
C out
L
O
A
D
R2
Adj
Up
COM
COM
Adjust Down: Add a resistor (R1), between pin 14 (Vo adjust) and pin 1 Vo(sense) 3.
Refer to Figure 1 and Table 2 for both the placement and value
of the required resistor, either (R1) or R2 as appropriate.
The values of (R1) [adjust down], and R2 [adjust up], can
also be calculated using the following formulas.
(R1)
=
Ro ( Va –Vr )
Vo – Va
R2
=
Ro ·Vr
Va – Vo
Where: Vo
Va
Vr
Ro
Rs
– Rs
– Rs
kΩ
Notes:
1. Use only a single 1% resistor in either the (R1) or R2
location. Place the resistor as close to the ISR as
possible.
2. Never connect capacitors from Vo adjust to either
GND, Vout, or the Remote Sense pin. Capacitance
added to the Vo adjust pin will affect the stability of
the ISR.
3. If the Remote Sense feature is not being used, the
resistor (R1) may be connected between pin 14 (Vo
adjust) and pins 11–13 (Vout).
kΩ
= Original output voltage
= Adjusted output voltage
= The reference voltage (Table 1)
= The multiplier resistance (Table 1)
= The internal series resistance (Table 1)
4. Adjusting the output voltage of the PT6523 (2.5V
model) higher than the factory pre-trimmed output
voltage may increase the minimum input voltage
specified for the part. This model must comply with
the following requirements.
PT6523:
Vin(min) = (Va + 0.5)V or 3.1V, whichever is greater.
Table 1
ADJUSTMENT AND FORMULA PARAMETERS
Series Pt #
Vo (nom)
Va (min)
Va (max)
Vr (V)
Ω)
Ro (kΩ
Ω)
Rs (kΩ
PT6527
PT6522
PT6526
PT6525
PT6523
PT6521
1.2
1.09
1.52
0.8
10.0
24.9
1.5
1.47
1.73
1.27
10.2
49.9
1.8
1.75
2.05
1.27
10.0
49.9
2.1
1.95
2.45
1.27
10.0
33.2
2.5
2.25
2.85
1.27
10.0
33.2
3.3
2.75
3.75
1.27
10.0
24.9
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Application Notes continued
PT6520 Series
Table 2
PT6520 ADJUSTMENT RESISTOR VALUES
Series Pt #
Vo (nom)
Va (req’d)
1.1
1.15
1.2
1.25
1.3
1.35
1.4
1.45
1.47
1.5
1.55
1.6
1.65
1.7
1.75
1.8
1.85
1.9
1.95
2.0
2.05
2.1
2.15
2.2
2.25
2.3
2.35
2.4
2.45
2.5
2.55
2.6
2.65
2.7
2.75
2.8
2.85
R1 = (Blue)
PT6527
1.2V
PT6522
1.5V
PT6526
1.8V
PT6525
2.1V
PT6523
2.5V
(5.1)kΩ
(45.1)kΩ
135.0kΩ
55.1kΩ
28.4kΩ
15.1kΩ
7.1kΩ
4.7kΩ
1.8kΩ
(18.1)kΩ
209.0kΩ
79.6kΩ
36.5kΩ
14.9kΩ
(46.1)kΩ
204.0kΩ
77.1kΩ
34.8kΩ
13.6kΩ
(12.1)kΩ
(39.8)kΩ
(123.0)kΩ
221.kΩ
93.8kΩ
51.5kΩ
30.3kΩ
17.6kΩ
9.1kΩ
3.1kΩ
Series Pt #
Vo (nom)
Va (req’d)
PT6521
3.3V
2.75
2.8
2.85
2.9
2.95
3.0
3.05
3.1
3.15
3.2
3.25
3.3
3.35
3.4
3.45
3.5
3.55
3.6
3.65
3.7
3.75
(2.0)kΩ
(5.7)kΩ
(10.2)kΩ
(15.9)kΩ
(23.1)kΩ
(32.8)kΩ
(46.3)kΩ
(66.6)kΩ
(100.0)kΩ
(168.0)kΩ
(371.0)kΩ
229.0kΩ
102.0kΩ
59.8kΩ
38.6kΩ
25.9kΩ
17.4kΩ
11.4kΩ
6.9kΩ
3.3kΩ
(6.0)kΩ
(18.3)kΩ
(38.8)kΩ
(79.8)kΩ
(203.0)kΩ
221.0kΩ
93.8kΩ
(See Note 4) 51.5kΩ
30.3kΩ
17.6kΩ
9.1kΩ
3.1kΩ
R2 = Black
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
PT6520 Series
Capacitor Recommendations for the PT6520 Series of
Integrated Switching Regulators
Tantalum Capacitors
Tantalum type capacitors may be used for the output but
only the AVX TPS series, Sprague 593D/594/595 series
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 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 Capacitors:
The recommended input capacitance is determined by
1.0 ampere minimum ripple current rating and 330µF
minimum capacitance (300µF for Oscon® or low ESR
tantalum). Ripple current and <100mΩ 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× the maximum
DC voltage + AC ripple. This is necessary to insure
reliability for input voltage bus applications
Capacitor Table
Table 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.
Output Capacitors:
The ESR of the required capacitor (Cout) must not be
greater than 150mΩ. Electrolytic capacitors have poor
ripple performance at frequencies greater than 400kHz
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 type capacitor
part numbers are identified in Table 1.
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
(Equivalent Series Resistance at 100kHz) are critical parameters
necessary to insure both optimum regulator performance and
long capacitor life.
Table 1: Input/Output Capacitors
Capacitor
Vendor/
Component
Series
Capacitor Characteristics
Quantity
Working
Voltage
Value(µF)
(ESR) Equivalent
Series Resistance
85°C Maximum Ripple
Current(Irms)
Physical
Size(mm)
Input
Bus
Output
Bus
Panasonic
FC
25V
35V
35V
560µF
390µF
330µF
0.0065Ω
0.065Ω
0.117Ω
1205mA
1205mA
555mA
12.5x15
12.5x15
8x11.5
1
2
N/R
1
1
1
EEUFC1E561S
EEUFC1V391S
EEUFC1C331
United
Chemi-Con
LXV/FS/
LXZ
16V
35V
10V
20V
330µF
470µF
330µF
150µF
0.120Ω
0.052Ω
0.025Ω
0.030÷2 Ω
555mA
1220mA
3500mA
3200mA
8x12
10x20
10x10.5
10x10.5
N/R
1
1
2
1
1
1
2
LXZ16VB331M8X12LL
LXZ35VB471M10X20LL
10FS330M
20FS150M
Nichicon
PL/ PM
35V
35V
50V
560µF
330µF
470µF
0.048Ω
0.065÷2 Ω
0.046Ω
1360mA
1020mA
1470mA
16x15
12.5x15
18x15
1
1
1
1
1
1
UPL1V561MHH6
UPL1V331MHH6
UPM1H4711MHH6
Panasonic
FC
(Surface Mtg)
10V
35V
16V
1000µF
330µF
330µF
0.043Ω
0.065Ω
0.150Ω
1205mA
1205mA
670mA
12x16.5
12.5x16
10x10.2
1
1
N/R
1
1
1
EEVFC1A102LQ
EEVFC1V331LQ
EEVFC1C331P
Oscon- SS
SV
10V
10V
20V
330µF
330µF
150µF
0.025Ω
0.025Ω
0.024÷2 Ω
>3500mA
>3800mA
3600mA
10.0x10.5
10.3x10.3
10.3x10.3
1
1
2
1
1
2
10SS330M
10SV300M
20SV150M
SV= Surface Mount
AVX
Tantalum
TPS
10V
10V
10V
330µF
330µF
220µF
0.100÷2 Ω
0.100÷2 Ω
0.095Ω
>2500mA
>3000mA
>2000mA
7.3Lx
4.3Wx
4.1H
2
2
2
1
1
2
TPSV337M010R0100
TPSV337M010R0060
TPSV227M0105R0100
10V
10V
330µF
220µF
0.033Ω
0.07Ω÷2 =0.035Ω
1400mA
>2000mA
7.3Lx5.7W
x 4.0H
2
2
1
2
T510X337M010AS
T495X227M010AS
10V
10V
330µF
220µF
0.045Ω
0.065Ω
2350mA
>2000mA
7.3Lx
6.0Wx
4.1H
2
2
1
2
4D337X0010R2T
594D227X0010D2T
Kemet
T510/
T495
Sprague
594D
N/R –Not recommended. The ripple current rating and ESR does not meet the requirements.
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Vendor Number
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