Document Outline
- Return to Contents
- List of Figures
- 1. Transient Load Voltage Response
- 2. Protection Diodes and CADJ
- 3. Overload Recovery
- 4. Adjustable Voltage Regulator
- 5. Connection for Best Load Regulation
- 6. Connection for Best Load Regulation
- Features
- Applications
- General Description
- Pin Configurations
- Typical Operating Circuit
- Ordering Information
- Absolute Maximum Ratings*
- Electrical Characteristics: TA = Operating Temperature Range, 4.75V VIN 5.25V, unless
- Simplified Schematic
- Applications
- General
- Stability and Transient Response
- Protection Diodes
- Overload Recovery
- Ripple Rejection
- Output Voltage
- Load Regulation
- Thermal Considerations
- Typical Applications
- Typical Characteristics
- Package Dimensions
- Sales Offices
1
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
7A / 5A / 4.6A / 3A, FAST RESPONSE, LOW DROPOUT
POSITIVE LINEAR VOLTAGE REGULATORS
The TCL1584/1585/1587 are low dropout, positive lin-
ear voltage regulators. They have a maximum current
output specification of 7A, 5A, 4.6A and 3A respectively.
All three devices are supplied in fixed and adjustable output
voltage versions.
Good transient load response combined with low drop-
out voltage makes these devices ideal for the latest low
voltage microprocessor power supplies. Additionally, short-
circuit, thermal and safe operating area (SOA) protection is
provided internally to ensure reliable operation.
The TCL1587, TCL1585 and TCL1584 are available in
a 3-pin TO-220 tabbed power package and in a 3-pin surface
mount DDPAK-3 package.
TYPICAL OPERATING CIRCUIT
FEATURES
s
Fixed and Adjustable Voltages ........ 1.5V and 3.3V
s
Optimized for Low Voltage Applications
s
Output Current Capability .......... 7A / 5A / 4.6A / 3A
s
Guaranteed Dropout Voltage up to Full Rated
Output
s
Integrated Thermal and Short-Circuit Protection
s
Compact 3-Pin Surface-Mount and Thru-Hole
Standard Power Packages
s
V
REF
Accuracy ................................................. 2.0%
s
Load Regulation ............................................. 0.05%
APPLICATIONS
s
Pentium
TM*
, PentiumPro
TM*
CPU Power Supplies
s
PowerPC
TM*
CPU Power Supplies
s
PentiumPro
TM*
System GTL+ Bus Terminators
s
Low-Voltage, High Speed Microprocessors
s
Post-Regulator for Switch-Mode Power Supplies
GENERAL DESCRIPTION
ORDERING INFORMATION
Part Number
Package
Temp. Range
TCL1584-3.3CAB
TO-220-3
0
C to + 70
C
TCL1584-3.3CEB
DDPAK-3
0
C to + 70
C
TCL1584-ADJCAB
TO-220-3
0
C to + 70
C
TCL1584-ADJCEB
DDPAK-3
0
C to + 70
C
TCL1585-1.5CAB
TO-220-3
0
C to + 70
C
TCL1585-1.5CEB
DDPAK-3
0
C to + 70
C
TCL1585-3.3CAB
TO-220-3
0
C to + 70
C
TCL1585-3.3CEB
DDPAK-3
0
C to + 70
C
TCL1585-ADJCAB
TO-220-3
0
C to + 70
C
TCL1585-ADJCEB
DDPAK-3
0
C to + 70
C
TCL1587-1.5CAB
TO-220-3
0
C to + 70
C
TCL1587-1.5CEB
DDPAK-3
0
C to + 70
C
TCL1587-3.3CAB
TO-220-3
0
C to + 70
C
TCL1587-3.3CEB
DDPAK-3
0
C to + 70
C
TCL1587-ADJCAB
TO-220-3
0
C to + 70
C
TCL1587-ADJCEB
DDPAK-3
0
C to + 70
C
TCL1584
TCL1585
TCL1587
TCL1584/1585/1587-04 6/6/97 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices.
V
OUT
= 3.3V
TCL158x-3.3
GND
V
IN
= 5V
C1 = 10
F
C2*
(Tantalum)
V
IN
V
OUT
Fixed Output Voltage Version
V
OUT
=
(1+ R1/R2)V
REF
TCL158x
ADJ
V
IN
= 5V
C1 = 10
F
C2*
(Tantalum)
V
IN
V
OUT
Adjustable Output Voltage Version
*NOTE: C2 is required to ensure output stability. Minimum 22
F (TCL1584) or 10
F (TCL1585/7),
low ESR tantalum type. Larger values may be required for high output current transient
regulation. See
Applications section.
R1
R2
PIN CONFIGURATIONS
*All Trademarks and Trade Names are the property of their respective owners.
V
OUT
V
IN
ADJ/GND
ADJ/GND
V
OUT
V
IN
1
2
3
1
2
3
TCL1584CAB
TCL1585CAB
TCL1587CAB
TCL1584CEB
TCL1585CEB
TCL1587CEB
TO-220-3
DDPAK-3
NOTE: For TO-220
JA
= 53
C/W. For DDPAK-3
JA
= 76
C/W.
JA
for both packages
are specified without external heat sinks. See Applications Section for details.
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
2
TCL1584/1585/1587-04 6/6/97
ELECTRICAL CHARACTERISTICS:
T
A
= Operating Temperature Range, 4.75V
V
IN
5.25V, unless
otherwise specified.
Parameter
Device
Test Conditions
Min
Typ
Max
Unit
Reference TCL1584
1.5V
(V
IN
V
OUT
)
3V, 10mA
I
OUT
7A
1.225
1.25
1.275
V
Voltage
TCL1585
1.5V
(V
IN
V
OUT
)
5.75V, 10mA
I
OUT
4.6A, T
J
25
C
1.5V
(V
IN
V
OUT
)
5.75V, 10mA
I
OUT
4A, T
J
< 25
C
TCL1587
1.5V
(V
IN
V
OUT
)
5.75V, 10mA
I
OUT
3A
Output
TCL1587-1.5
4.75V
V
IN
7V, 0mA
I
OUT
3A
Voltage
TCL1584-3.3
4.75V
V
IN
6.3V, 0mA
I
OUT
7A
3.235
3.30
3.365
V
TCL1585-3.3
4.75V
V
IN
7V, 0mA
I
OUT
4.6A, T
J
25
C
4.75V
V
IN
7V, 0mA
I
OUT
4A, T
J
< 25
C
TCL1587-3.3
4.75V
V
IN
7V, 0mA
I
OUT
3A
Line
TCL1584/5/7
2.75V
V
IN
7V, I
OUT
= 10mA
--
0.005
0.2
%
Regulation TCL1587-1.5
4.75V
V
IN
7V, I
OUT
= 0mA
(Notes 1, 2) TCL1584/5/7-3.3
4.75V
V
IN
7V, I
OUT
= 0mA
Load
TCL1584/5/7
(V
IN
V
OUT
) = 3V, T
J
= 25
C, 10mA
I
OUT
I
FULL LOAD
--
0.05
0.3
%
Regulation TCL1587-1.5
V
IN
= 5V, T
J
= 25
C, 0mA
I
OUT
I
FULL LOAD
(Notes 1,
TCL1584/5/7-3.3
V
IN
= 5V, T
J
= 25
C, 0mA
I
OUT
I
FULL LOAD
2, 3)
Over Operating Temperature Range
--
0.05
0.5
Dropout
TCL1585/7
V
REF
= 1%, I
OUT
= 3A
--
1.15
1.30
V
Voltage
TCL1587-1.5
V
OUT
= 1%, I
OUT
= 3A
TCL1585/7-3.3
V
OUT
= 1%, I
OUT
= 3A
TCL1585
V
REF
= 1%, I
OUT
= 4.6A, T
J
25
C
--
1.20
1.40
V
V
REF
= 1%, I
OUT
= 4A, T
J
< 25
C
TCL1585-3.3
V
OUT
= 1%, I
OUT
= 4.6A, T
J
25
C
V
OUT
= 1%, I
OUT
= 4A, T
J
< 25
C
TCL1584
V
REF
= 1%, I
OUT
= 6A
TCL1584-3.3
V
OUT
= 1%, I
OUT
= 6A: T
J
25
C
--
1.20
1.30
V
T
J
< 25
C
--
1.30
1.35
TCL1584
V
REF
= 1%, I
OUT
= 7A
--
1.25
1.40
V
TCL1584-3.3
V
OUT
= 1%, I
OUT
= 7A
Current
TCL1584
(V
IN
V
OUT
) = 3V
7.10
8.25
--
A
|
Limit
TCL1584-3.3
(V
IN
V
OUT
) = 3V
(Note 3)
TCL1585
(V
IN
V
OUT
) = 5.5V: T
J
< 25
C
4.10
5.25
--
A
TCL1585-3.3
(V
IN
V
OUT
) = 5.5V: T
J
25
C
4.60
5.25
TCL1587
(V
IN
V
OUT
) = 5.5V
3.10
3.75
--
A
TCL1587-1.5
(V
IN
V
OUT
) = 5.5V
TCL1587-3.3
(V
IN
V
OUT
) = 5.5V
Temperature TBD
TBD
Coefficient
ADJ Pin
TCL1584/5/7
--
55
120
A
Current
ABSOLUTE MAXIMUM RATINGS*
Input Voltage (V
IN
to GND) ........................................... 7V
Operating Junction Temperature Range
Control Circuitry ................................... 0
C to +125
C
Output Transistor ................................. 0
C to +150
C
Power Dissipation ..................... See
Applications Section
Storage Temperature (unbiased) .......... 65
C to +150
C
Lead Temperature (Soldering, 10 sec) ................. +300
C
*This is a stress rating only, and functional operation of the device at these
or any other conditions beyond those indicated in the operation section of
the specifications is not implied. Exposure to absolute maximum ratings
conditions for extended periods of time may affect device reliability.
3
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
ELECTRICAL CHARACTERISTICS: (Cont.)
T
A
= Operating Temperature Range, 4.75V
V
IN
5.25V,
unless otherwise specified.
Parameter
Device
Test Conditions
Min
Typ
Max
Unit
ADJ Pin
TCL1584
1.5V
(V
IN
V
OUT
)
3V, 10mA
I
OUT
I
FULL LOAD
--
0.2
5
A
Current
TCL1585/7
1.5V
(V
IN
V
OUT
)
5.75V, 10mA
I
OUT
I
FULL LOAD
Change
(Note 3)
Minimum
TCL1584/5/7
1.5V
(V
IN
V
OUT
)
5.75V
--
2
10
mA
Load
Current
Quiescent
TCL1587-1.5
V
IN
= 5V
--
8
13
mA
Current
TCL1584/5/7-3.3 V
IN
= 5V
Ripple
TCL1584
f = 120Hz, C
OUT
= 25
F Tant. (V
IN
V
OUT
) = 2.5V, I
OUT
= 7A
60
72
--
dB
Rejection
TCL1584-3.3
f = 120Hz, C
OUT
= 25
F Tant., V
IN
= 5.8V, I
OUT
=
7A
TCL1585
f = 120Hz, C
OUT
= 25
F Tant., (V
IN
V
OUT
) = 3V, I
OUT
= 4.6A, T
J
25
C
f = 120Hz, C
OUT
= 25
F Tant., (V
IN
V
OUT
) = 3V, I
OUT
= 4A, T
J
25
C
TCL1585-3.3
f = 120Hz, C
OUT
= 25
F Tant.,V
IN
= 6.3V, I
OUT
= 4.6A, T
J
25
C
f = 120Hz, C
OUT
= 25
F Tant.,V
IN
= 6.3V, I
OUT
= 4.6A, T
J
25
C
TCL1587
f = 120Hz, C
OUT
= 25
F Tant., (V
IN
V
OUT
) = 3V, I
OUT
= 3A
TCL1587-1.5
f = 120Hz, C
OUT
= 25
F Tant., V
IN
= 5.0V, I
OUT
= 3A
TCL1587-3.3
f = 120Hz, C
OUT
= 25
F Tant., V
IN
= 6.3V, I
OUT
= 3A
Thermal
TCL1584/5/7
T
A
= 25
C, 30msec Pulse
--
0.004
0.02
%/W
Regulation TCL1587-1.5
T
A
= 25
C, 30msec Pulse
TCL1584/5/7-3.3
T
A
= 25
C, 30msec Pulse
Temperature
V
IN
= 5V, I
OUT
= 0.5A
--
0.5
--
%
Stability
Long Term
T
A
= 125
C, 1000Hrs.
--
0.03
1.0
%
Stability
RMS
T
A
= 25
C, 10Hz
f
10kHz
--
0.003
--
%
Output
Noise (%
of V
OUT
)
Thermal
TCL1584
"A" pkg. (TO-220): Control Circuitry/Power Transistor
--
--
0.65/2.7
C/W
Resistance TCL1585
"A" pkg. (TO-220): Control Circuitry/Power Transistor
--
--
0.7/3.0
C/W
(Junction to TCL1585
"E" pkg. (TO-263): Control Circuitry/Power Transistor
--
--
0.7/3.0
C/W
Case,
JA
)
TCL1587
"A" pkg. (TO-220): Control Circuitry/Power Transistor
--
--
0.7/3.0
C/W
TCL1587
"E" pkg. (TO-263): Control Circuitry/Power Transistor
--
--
0.7/3.0
C/W
NOTES: 1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant
junction temperature by low duty cycle pulse testing.
2. Load and line regulation are guaranteed up to the maximum power dissipation (25W for the TCL1584 in "A" pkg., 26.5W for the TCL1585 in
"A" pkg., 18W for the TCL1587 in "A" pkg.). Power dissipation is determined by input/output voltage differential and output current. Guaranteed
maximum output current/power will not be available over full input/output voltage range.
3. I
FULL LOAD
is defined as the maximum value of output load current as a function of input-to-output voltage. I
FULL LOAD
is a nominal 7A for
TCL1584, decreasing to approximately 3A as V
IN
V
OUT
increases from 3V to 7V. For all other fixed voltage TCL1585's, I
FULL LOAD
is 4A. For
the TCL1587, I
FULL LOAD
is 3A. The TCL1585 and 1587 have constant current limit with respect to V
IN
and V
OUT
.
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
4
TCL1584/1585/1587-04 6/6/97
SIMPLIFIED SCHEMATIC
+
TCL1584/5/7
THERMAL
LIMIT
ADJ
V
OUT
V
IN
FOR FIXED VOLTAGE DEVICE
GND
OUTPUT CURRENT (A)
Typical Dropout Voltage vs. Output Current
INPUT/OUTPUT DIFFERENTIAL (V)
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
IFULL LOAD
5
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
APPLICATIONS
General
The TCL158x family of devices combine high current
output (up to 7A) with low dropout voltage and built-in fault
protection in a traditional three-terminal LDO format. All
three device types are available in fixed output voltage and
adjustable output versions. Fault protection includes short-
circuit current limit, over-temperature limit, and safe-operat-
ing-area (SOA) governing.
These devices are pin-compatible upgrades for the
1083/1084/1085 family of LDO's. However, the TCL158x
family delivers lower dropout voltage, faster load transient
response and improved internal frequency compensation.
Maximum supply voltage rating is 7.0V.
Modern processors cycle load current from near zero to
several amps in a time period measured in tens of nanosec-
onds. Load step response requirements are worsened by
tighter output voltage tolerances. The TCL1584/85/87 fam-
ily of regulators meets these stringent requirements without
an obnoxious amount of output capacitance, saving both
board space and cost.
Stability and Transient Response
Like most low dropout voltage regulators, the TCL158x
devices require the use of output capacitors to maintain
stability. Normally a 22
F solid tantalum or a 100
F alumi-
num electrolytic unit will ensure stability over all operating
conditions. Keep in mind that commercially available ca-
pacitors can have significant non-ideal effects such as
capacitance value tolerance, temperature coefficient, ESR,
ESL. The TCL158x devices are optimized for use with low
ESR (<1
) capacitors.
On the adjustable voltage versions, bypassing the ADJ
pin will improve ripple rejection and transient response. This
is discussed in the
Ripple Rejection section. This bypassing
increases the required output capacitance value. The previ-
ously suggested minimum values (22
F and 100
F) take
this into account. If no bypassing is used, lower values of
output capacitance may be used.
Transient regulation is directly related to output capaci-
tance value. For applications which require large load cur-
rent step changes, it is recommended that large output
capacitors (>100
F) be used. The value of the output
capacitor can be increased without limit and will only im-
prove transient regulation.
In a typical high-performance microprocessor applica-
tion, the sudden transients can be so fast that the output
decoupling network must handle the sudden current de-
mand until the internal voltage regulator is able to respond.
In this case the non-ideal effects of the output capacitor are
critical in determining the regulator's response. Output volt-
age response to step load current change is illustrated in
Figure 1. The capacitor's ESR and ESL cause immediate
step changes in the output voltage. These are calculated as
follows:
V
ESR
=
I x ESR
DV
ESL
= DI/Dt x ESL
To reduce the initial voltage droop, one should select
low ESR and ESL capacitors. It should also be noted that the
ESR effect is multiplied by absolute change in load current
while the ESL effect is multiplied by the
rate of change in load
current. After the initial voltage drop, the capacitor value
dominates the rate of change in voltage. This rate is calcu-
lated as follows:
V =
t x
I/C
Figure 1. Transient Load Voltage Response
ESR
EFFECTS
ESL
EFFECTS
POINT AT WHICH REGULATOR
TAKES CONTROL
CAPACITANCE
EFFECTS
SLOPE,
V =
I
t C
Typically high quality ceramic and tantalum capacitors
must be used in combination to minimize ESR and maximize
C. This decoupling network must also be placed close to the
microprocessor to reduce ESL (parasitic board trace induc-
tance). If possible, the capacitors should be placed
inside
the microprocessor socket cavity. Of course, robust power
and ground planes will also improve performance by reduc-
ing parasitic voltage drops.
The TCL1584 has an adaptive current limiting scheme
where to ensure SOA for the output transistor, the current
limit is reduced for increasing input to output differential. This
means that the TCL1584 exhibits a
negative resistance
characteristic under certain conditions. This is a common
technique in LDO design to ensure SOA - especially LDO's
with high maximum input voltage ratings. This negative
resistance can interact with the external capacitance and
inductance and cause oscillations during current limit. This
effect is highly dependent on system parameters and is
difficult to predict. However this oscillation, if it occurs, will
not damage the regulator and can be ignored if the system
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
6
TCL1584/1585/1587-04 6/6/97
Figure 3. Overload Recovery
I
OUT
Current Limit Curve
Load Line
Start Up
Point
Unrecoverable
I-V Point
V
IN
V
OUT
(Constant
V
IN)
parameters will allow it. Typically, increasing the output
capacitance helps reduce the oscillation. NOTE: The
TCL1585 and TCL1584 have fixed current limit over the
entire voltage range and are not susceptible to this phenom-
enon.
Protection Diodes
The TCL158x family of devices do not normally require
any external current limiting circuitry such as protection
diodes, frequently used with older LDO regulators. A diode
is internally present between the output and input which is
capable of handling short-duration surge currents of up to
100A. This capability typically ensures safe operation ex-
cept for the case where output capacitance is exceedingly
large (>1000
F) and the input is suddenly shorted to ground.
This situation can produce excessive reverse current in the
device - enough to cause damage. An external high current
diode should be used as shown in Figure 2.
The ADJ pin does not normally need protection diodes
either. It can handle
7V without any performance degrada-
tion or device damage. Current at this pin is internally limited
by a series resistor so the bypass capacitors do not present
any danger. Of course, exceeding 7V differential between
any two pins will cause catastrophic junction breakdowns
and possible damage to the device.
Overload Recovery
The built-in Short Circuit and Safe-Operating-Area (SOA)
protection function of the TCL158x family can cause sec-
ondary effects which must be considered for robust system
design. The behavior of the regulator under heavy loads
(short circuit) at start-up is such that the output voltage will
remain low while sourcing maximum current until the load is
removed or reduced. Normally, the output voltage will rise as
the load is reduced and trace a line I-V relationship accord-
ing to the SOA limit. If the load line intersects this output
curve at two points the output voltage may not recover from
the heavy load/short-circuit condition. This condition is illus-
trated in Figure 3. The current limit constraint does not allow
any load point above it and the load line is defined absolutely
by the I-V characteristics of the load (a resistor, in this case).
Under these conditions it may be necessary to cycle the
power supply off and then on again. This phenomenon is
common for LDO's with fold-back current limiting schemes.
NOTE: Overload recovery is
always guaranteed on the
TCL1585 and TCL1587 because of the constant current
limit characteristic.
Ripple Rejection
A typical ripple rejection curve for the fixed output
voltage devices is shown in Figure 3. It is possible to obtain
improved performance in ripple rejection by using the ad-
justable output TCL158x with a bypass capacitor (C
ADJ
)
shown in Figure 2. This capacitor should be chosen to have
a value such that its impedance at the ripple frequency is
less than R1 (see Figure 2.). Usually this is on the order of
100
. Example: If R1 = 100
and f
RIPPLE
= 120Hz, the
bypass capacitor should be chosen to be 22
F or greater. If
these conditions are met the ripple rejection will be improved
by a factor of V
OUT
/1.25 when compared to the performance
of the fixed output devices.
Figure 2. Protection Diodes and C
ADJ
+
+
VOUT
C1
10
F
C2
22
F
OUT
IN
TCL1584-3.3
D1
1N4002
(OPTIONAL)
GND
VIN
+
+
+
VOUT
R1
R2
C1
10
F
C2
22
F
C
ADJ
OUT
IN
TCL1584
D1
1N4002
(OPTIONAL)
ADJ
VIN
7
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
Output Voltage
The output voltage for the fixed output versions of the
TCL158x is set internally and cannot be adjusted. For the
adjustable output versions, the output voltage is set by two
external resistors: R1 and R2 (see Figure 3). A 1.25V
reference voltage is maintained between the OUTPUT pin
and the ADJ pin. NOTE: the ADJ pin typically will source
55
A. R1 should be chosen to conduct at least the specified
minimum load current of 10mA (i.e. at most 125
). Now R2
will determine the total output voltage according to the
equation below:
V
OUT
= V
REF
(1+ R2/R1) + R2(I
ADJ
)
The contribution due to the I
ADJ
term is relatively small
as I
ADJ
is only 55
A compared to 10mA for the total current
in the adjust circuit.
Figure 4. Adjustable Voltage Regulator
In both cases, because the effect of parasitic trace
resistance (R
P
) cannot be completely eliminated, it is impor-
tant to keep the positive output lead as short as possible.
Otherwise, at high output currents, the load regulation will
degrade appreciably. Example:
R
P
= 5m
I
OUT
= 3A
V
DROP
= (0.005) x (3) = 15mV
V
OUT
V
REF
C2
22
F
I
ADJ
55
A
R2
R1
OUT
IN
TCL1584
ADJ
V
IN
V
OUT
= V
REF
(
1+ R2
)
+ I
ADJ
(R2)
R1
+
C1
10
F
Load Regulation
Because the TCL158x family are three terminal de-
vices, it is not possible to perform true Kelvin load voltage
sensing. Therefore load regulation is limited somewhat by
parasitic trace resistance. The load regulation specifications
are measured
directly at the TCL158x package. To minimize
degradation in load regulation performance the following
guidelines should be used.
For fixed voltage devices, the GND pin should be
connected directly to the negative side of the load instead of
to a common ground bus. This provides Kelvin sensing at
the negative side while the positive side is still limited by R
P
(See Figure 5).
For adjustable output devices, the bottom of R2 con-
nects to the negative side of the load. For the positive side,
best regulation is obtained when the top of R1 is connected
directly to the TCL158x and not to the load (See Figure 6).
If R1 connects to the load the effective resistance between
the output and the load is:
R
P
x (1 + R2/R1)
Figure 5. Connection for Best Load Regulation
Figure 6. Connection for Best Load Regulation
R
L
OUT
IN
TCL1584-3.3
RP
PARASITIC
LINE RESISTANCE
GND
V
IN
R
L
OUT
IN
TCL1584
RP
PARASITIC
LINE RESISTANCE
*CONNECT R1 TO CASE
CONNECT R2 TO LOAD
ADJ
V
IN
R1*
R2*
Thermal Considerations
The TCL158x family includes built-in thermal overload
protection. However, maximum operating junction tempera-
ture
must not be exceeded for any condition. Since these
devices are capable of dissipating up to 25W or more under
some conditions, careful thermal design is required for
reliable, continuous operation. In most cases, external heat
sinking will be required.
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
8
TCL1584/1585/1587-04 6/6/97
When generating the overall thermal design, it is impor-
tant to consider all sources of thermal resistance between
the silicon die and ambient - junction-to-case (
JC
), case-to-
heat sink (
CH
), heat sink-to-ambient (
HA
). NOTE: there
are two separate
JC
specifications for the power transistor
and the control circuitry. Both junction temperatures must be
calculated and kept under each respective maximum limit to
ensure proper operation. This
JC
is for the physical path
between the die and the bottom metal portion of the case
(both TO-220 and DDPAK-3. Heat flow will be greatest
through this path. It is important that good thermal coupling
is made between the case and heat sink. If electrical
isolation from the heat sink is not required, it is recom-
mended that thermally conductive compound be used.
Otherwise, use a thermally conductive dielectric spacer.
The following is a thermal design example:
Using a TCL1585-3.3 in a TO-220 package:
Assumptions:
T
A
= +70
C
V
IN
= 5.25V (5V + 5%)
V
OUT
= 3.30V
I
OUT
= 4.6A
HA
= 3.5
C/W (heat sink-to-ambient)
CH
= 1.5
C/W (case-to-heat sink)
JC
= 3
C/W (power transistor)
JC
= 0.7
C/W (control circuitry)
Power dissipation:
P
D
= (V
IN
V
OUT
)(I
OUT
) = (5.25 3.3)(4.6) = 8.97W
Junction Temperatures:
T
J
= T
A
+ P
D
(
HA
+
CH
+
JC
)
Control Circuitry:
T
J
= 70 + 8.97(3.5 + 1.5 + 0.7) = 121.1
C
Power Transistor:
T
J
= 70 + 8.97(3.5 + 1.5 + 3) = 141.8
C
These values for T
J
fall within the maximum allowed
junction temperature for each die section indicating ad-
equate heat sinking with some margin.
NOTE: Without heat sinking, the thermal resistance for the
TO-220 and DDPAK-3 packages are 53
C/W and
76
C/W respectively.
9
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
TYPICAL APPLICATIONS
V
OUT
V
IN
Typical IntelTM* 486Dx4 Microprocessor Application
PLACE AT MICROPROCESSOR SOCKET V
CC
PINS
ESR OF THE 47
F IS < 0.1
GND
TCL1587-3.3
C1
10
F
10V
C2
22
F
10V
C3 TO C6
47
F
10V
C7 TO C15
0.1
F
C16 TO C24
0.01
F
V
IN
4.75V
3.30V
3A
V
OUT
V
IN
IntelTM* 90MHz PentiumTM* Power Supply
PLACE IN MICROPROCESSOR
SOCKET CAVITY
THERMALLOY
7020B-MT
ADJ
TCL1585
C1 TO C3
220
F
10V
AVX TPS
3 EACH
C5 TO C10
100
F
10V
AVX TPS
6 EACH
C11 TO C20
1
F
16V
AVX Y5V 0805
10 EACH
AVX Corp. (803) 448-9411
Sanyo Video Components (USA) Corp. (619) 661-6322
Thermalloy Inc. (214) 243-4321
DO NOT SUBSTITUTE COMPONENTS
C4
330
F
16V
AVX X7R 0805
R1
110
0.1%
R2
187
0.1%
4.75V TO 5.25V
3.38V
4.6A
100
sec/DIV
*TRANSIENT RESPONSE MEASURED WITH AN
INTEL POWER VALIDATORTM. V
OUT
IS MEASURED
AT THE POWER VALIDATOR.
Transient Response for 3.8A Load Current Step*
VOUT
50mV/DIV
IOUT
2A/DIV
All Trademarks and Trade Names are the property of their respective owners.
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
10
TCL1584/1585/1587-04 6/6/97
TYPICAL APPLICATIONS (Cont.)
Typical IntelTM* PentiumTM* Pro GTL+ Bus Terminator Application Using TCL1587-1.5
GND
TCL1587-1.5
C1 = 10
F
C2 = 10
F
(Tantalum)
GTL+ Bus (Z
O
)
C3 =1
F x 5
(Ceramic)
V
IN
= 5V or 3.3V
V
IN
= 5V or 3.3V
V
IN
V
OUT
GND
TCL1587-1.5
C1 = 10
F
NOTES: 1. It is recommended that the GTL+ bus be terminated at each end by a separate regulator to avoid power distribution losses.
2. The GTL+ bus transmission line symbol will consist of all the components (chip set IC's) on the GTL+ bus.
3. R
REF
and 2R
REF
should be chosen such that V
REF
loading does not appreciably degrade V
REF
regulation.
Values <100 ohms should suffice for most applications.
4. R
TERM
will be determined by individual bus physical/electrical parameters. See CPU manufacturer documentation for
application information.
C2 = 10
F
(Tantalum)
C3 = 1
F x 5
(Ceramic)
V
OUT
= 1.5V @ 3A
R
TERM
= 100
x 71
Lines
R
TERM
= 100
x 71
Lines
R
REF
2R
REF
V
OUT
= 1.5V @ 3A
V
REF
= 1.0V
V
IN
V
OUT
*All Trademarks and Trade Names are the property of their respective owners.
11
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
TYPICAL CHARACTERISTICS
OUTPUT CURRENT (A)
TCL1584 Dropout Voltage vs.
Output Current
TCL1584 Short Circuit Current
vs. Input/Output Differential
DROPOUT VOLTAGE (V)
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
2
1
4
3
6
7
5
OUTPUT CURRENT (A)
TCL1585 Dropout Voltage vs.
Output Current
DROPOUT VOLTAGE (V)
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
1
2
3
5
4
TEMPERATURE (
C)
TCL1585 Short-Circuit Current
vs. Temperature
6.0
5.5
5.0
4.5
4.0
75 50 25 0
50 75 100 125 150 175
25
OUTPUT CURRENT (A)
TCL1587 Dropout Voltage vs.
Output Current
DROPOUT VOLTAGE (V)
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
0.5
1.0
1.5
2.5
3.0
2.0
INPUT/OUTPUT DIFFERENTIAL (V)
SHORT-CIRCUIT CURRENT (A)
SHORT-CIRCUIT CURRENT (A)
10
8
6
4
2
0
0
2
1
4
3
6
7
5
T = 125
C
T = 25
C
T = 5
C
MINIMUM
TEMPERATURE (
C)
TCL1587 Short-Circuit Current
vs. Temperature
5.0
4.5
4.0
3.5
3.0
75 50 25 0
50 75 100 125150 175
25
SHORT-CIRCUIT CURRENT (A)
TEMPERATURE (
C)
TCL1584 Load Regulation
vs. Temperature
0.10
0.05
0
0.05
0.10
0.15
0.20
OUTPUT VOLTAGE DEVIATION (%)
75 50 25 0
50 75 100 125 150 175
25
TEMPERATURE (
C)
TCL1585 Load Regulation
vs. Temperature
0.10
0.05
0
0.05
0.10
0.15
0.20
OUTPUT VOLTAGE DEVIATION (%)
75 50 25 0
50 75 100 125 150 175
25
TEMPERATURE (
C)
TCL1587 Load Regulation
vs. Temperature
0.10
0.05
0
0.05
0.10
0.15
0.20
OUTPUT VOLTAGE DEVIATION (%)
75 50 25 0
50 75 100 125 150 175
25
INDICATES GUARANTEED TEST POINT
T = 125
C
T = 5
C
T = 25
C
T = 125
C
T = 5
C
T = 25
C
INDICATES GUARANTEED TEST POINT
I = 4.6A
I = 7A
I = 3A
INDICATES GUARANTEED TEST POINT
T = 25
C
T = 5
C
T = 125
C
TCL1584
TCL1585
TCL1587
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
PRELIMINARY INFORMATION
12
TCL1584/1585/1587-04 6/6/97
TYPICAL CHARACTERISTICS (Cont.)
TCL1584/5/7 Ripple Rejection
vs. Frequency
TEMPERATURE (
C)
TCL1584/5/7 Minimum Load Current
vs. Temperature
5
4
3
2
1
0
MINIMUM LOAD CURRENT (mA)
75 50 25 0
50 75 100 125 150 175
25
RIPPLE REJECTION (dB)
FREQUENCY (Hz)
90
80
70
60
50
10
40
30
20
10
0
100
1k
10k
100k
TEMPERATURE (
C)
Output Voltage vs Temperature
Using Adjustable TCL1584/5/7
3.70
3.65
3.60
3.55
3.50
3.45
3.35
3.40
3.30
3.25
3.20
OUTPUT VOLTAGE (V)
75 50 25 0
50 75 100 125 150 175
25
CASE TEMPERATURE (
C)
*AS LIMITED BY MAXIMUM JUNCTION
TEMPERATURE
TCL1585/7 Maximum Power
Dissipation*
30
25
20
15
10
5
0
POWER (W)
50 60 70
80
100 110 120 130 140 150
90
TEMPERATURE (
C)
TCL1584/5/7-3.3 Output Voltage
vs.Temperature
3.70
3.65
3.60
3.55
3.50
3.45
3.35
3.40
3.30
3.25
3.20
OUTPUT VOLTAGE (V)
75 50 25 0
50 75 100 125 150 175
25
TEMPERATURE (
C)
TCL1584/5/7 Adjust Pin Current
vs. Temperature
100
90
80
70
60
50
30
40
20
10
0
ADJUST PIN CURRENT (
A)
75 50 25 0
50 75 100 125 150 175
25
TEMPERATURE (
C)
TCL1584/5/7-3.xx Quiescent
Current vs. Temperature
13
12
11
10
9
8
6
7
5
4
3
QUIESCENT CURRENT (mA)
75 50 25 0
50 75 100 125 150 175
25
CASE TEMPERATURE (
C)
*AS LIMITED BY MAXIMUM JUNCTION
TEMPERATURE
TCL1584 Maximum Power
Dissipation*
30
25
20
15
10
5
0
POWER (W)
50 60 70
80
100 110 120 130 140 150
90
TEMPERATURE (
C)
TCL1584/5/7 Reference Voltage
vs. Temperature
1.275
1.270
1.265
1.260
1.255
1.250
1.240
1.245
1.235
1.230
1.255
REFERENCE VOLTAGE (V)
75 50 25 0
50 75 100 125 150 175
25
TCL1584: (V
IN
V
OUT
)
2.5V
TCL1584/87 (V
IN
V
OUT
)
3V
0.5V
V
RIPPLE
2V
I
OUT
= I
FULL
LOAD
TCL1585
TCL1587
TCL1584
V
OUT
SET WITH 1% RESISTORS
VOUT = 3.6V
VOUT = 3.45V
VOUT = 3.38V
VOUT = 3.3V
VOUT = 3.3V
13
TCL1584
TCL1585
TCL1587
PRELIMINARY INFORMATION
7A / 5A / 4.6A / 3A, FAST RESPONSE,
LOW DROPOUT POSITIVE LINEAR
VOLTAGE REGULATORS
TCL1584/1585/1587-04 6/6/97
TO-220-3
PACKAGE DIMENSIONS
Dimensions: inches (mm)
DDPAK-3
Printed in the U.S.A.
.100 (2.54) TYP.
.037 (0.94)
.026 (0.66)
.370 (9.40)
.329 (8.38)
.067 (1.70)
.045 (1.14)
.605 (15.37)
.549 (13.95)
.410 (10.41)
.385 (9.78)
.183 (4.65)
.170 (4.32)
.055 (1.40)
.045 (1.14)
.010 (0.25)
.000 (0.00)
.110 (2.79)
.068 (1.72)
0.26 (0.66)
0.14 (0.36)
.051 (1.30)
.049 (1.24)
0
- 8
3
- 7
(5x)
.205 (5.21)
.195 (4.95)
.113 (2.87)
.103 (2.62)
.410 (10.41)
.390 (9.91)
.156 (3.96)
.146 (3.71)
DIA.
.258 (6.55)
.230 (5.84)
.560 (14.22)
.518 (13.16)
.105 (2.67)
.095 (2.41)
.037 (0.94)
.027 (0.69)
.055 (1.40)
.045 (1.14)
.244 (6.20)
.234 (5.94)
.185 (4.70)
.165 (4.19)
.055 (1.40)
.045 (1.14)
.594 (15.09)
.569 (14.45)
.115 (2.92)
.095 (2.41)
.0.20 (0.51)
.012 (0.30)
3
- 7.5
5 PLCS.
Sales Offices
TelCom Semiconductor
1300 Terra Bella Avenue
P.O. Box 7267
Mountain View, CA 94039-7267
TEL: 415-968-9241
FAX: 415-967-1590
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TelCom Semiconductor
Austin Product Center
9101 Burnet Rd. Suite 214
Austin, TX 78758
TEL: 512-873-7100
FAX: 512-873-8236
TelCom Semiconductor H.K. Ltd.
10 Sam Chuk Street, Ground Floor
San Po Kong, Kowloon
Hong Kong
TEL: 852-2324-0122
FAX: 852-2354-9957
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