Cherry Semiconductor CS5257A-1GT5, CS5257A-1GDPR5, CS5257A-1GDP5 Datasheet
V
SENSE
V
OUT
V
CONTROL
V
POWER
CS5257A-1
2.5V @ 7A
300mF
5V
Load
124
1%
124
1%
0.1mF
5V
100mF
5V
10mF
10V
3.3V
5.0V
Adjust
Features
Package Options
CS5257A-1
7A LDO 5-Pin Adjustable Linear Regulator
CS5257A-1
Description
Applications Diagram
5 Lead TO-220
1
1. V
SENSE
2. Adjust
3. V
OUT
4. V
CONTROL
5. V
POWER
Tab = V
OUT
1
Rev. 4/5/99
This new very low dropout regulator is designed to power the next
generation of advanced microprocessors. To achieve very low
dropout, the internal pass transistor
is powered separately from the control circuitry. Furthermore, with the
control and power inputs tied
together, this device can be used in
single supply configuration and
still offer a better dropout voltage
than conventional PNP-NPN based
LDO regulators. In this mode the
dropout is determined by the minimum control voltage.
It is supplied in five-terminal
TO-220 and D
2
PAK packages,
allowing for the implementation of
a remote-sense pin permitting very
accurate regulation of output voltage directly at the load, where it
counts, rather than at the regulator.
This remote sensing feature virtually eliminates output voltage variations due to load changes and resistive voltage drops. Typical load
regulation measured at the sense
pin is 1mV for an output voltage of
2.5V with a load step of 10mA to
7A.
The very fast transient loop
response easily meets the needs of
the latest microprocessors. In addition, a small capacitor on the Adjust
pin will further improve the transient capabilities.
Internal protection circuitry provides for Òbust-proofÓ operation,
similar to three-terminal regulators.
This circuitry, which includes overcurrent, short circuit, supply
sequencing and overtemperature
protection will self protect the regulator under all fault conditions.
The CS5257A-1 is ideal for generating a secondary 2-2.5V low voltage
supply on a motherboard where
both 5V and 3.3V are already available.
■ 1.25V to 5V V
OUT
at 7A
■ V
POWER
Dropout < 0.35V @ 7A
■ V
CONTROL
Dropout < 1.10V @
7A
■ 1.5% Trimmed Reference
■ Fast Transient Response
■ Remote Voltage Sensing
■ Thermal Shutdown
■ Current Limit
■ Short Circuit Protection
■ Drop-In Replacement for
LT1580
■ Backwards Compatible with
3-pin Regulators
1
5 Lead D2PAK
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
A Company
¨
Electrical Characteristics:
0¡C ² TA² 70¡C, 0¡C ² TJ² 150¡C, V
SENSE
= V
OUT
and V
Adj
=
0V; unless otherwise specified.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
CS5257A-1
2
Absolute Maximum Ratings
V
POWER
Input Voltage .................................................................................................................................................................6V
V
CONTROL
Input Voltage ...........................................................................................................................................................13V
Operating Junction Temperature Range...........................................................................................................0¡C ² TJ² 150¡C
Storage Temperature Range................................................................................................................................-65¡C to +150¡C
Lead Temperature Soldering
Wave Solder (through hole styles only) .....................................................................................10 sec. max, 260¡C peak
Reflow (SMD styles only) ......................................................................................60 sec. max above 183¡C, 230¡C peak
ESD Damage Threshold............................................................................................................................................................2kV
Reference Voltage V
CONTROL
= 2.75V to 12V, V
POWER
= 2.05V to 5.5V, 1.234 1.253 1.272 V
10mA ² I
OUT
² 7A (-1.5%) (+1.5%)
Line Regulation V
CONTROL
= 2.5V to 12V, V
POWER
= 1.75V to 5.5V, .02 .20 %
I
OUT
= 10mA
Load Regulation V
CONTROL
= 2.75V, V
POWER
= 2.05V, .04 .20 %
(Note 3) I
OUT
= 10mA to 7A, with remote sense
Minimum Load Current V
CONTROL
= 5V, V
POWER
= 3.3V, ÆV
OUT
= +1% 5 10 mA
(Note 1)
Control Pin Current V
CONTROL
= 2.75V, V
POWER
= 2.05V, I
OUT
= 100mA 6 10 mA
(Note 2) V
CONTROL
= 2.75V, V
POWER
= 2.05V, I
OUT
= 4A 30 60 mA
V
CONTROL
= 2.75V, V
POWER
= 1.75V, I
OUT
= 4A 33 70 mA
V
CONTROL
= 2.75V, V
POWER
= 2.05V, I
OUT
= 7A 60 180 mA
Adjust Pin Current V
CONTROL
= 2.75V, V
POWER
= 2.05V, I
OUT
= 10mA 60 120 µA
Current Limit V
CONTROL
= 2.75V, V
POWER
= 2.05V, ÆV
OUT
= -1.5% 7.1 10.0 A
Short Circuit Current V
CONTROL
= 2.75V, V
POWER
= 2.05V, V
OUT
= 0V 5.0 9.0 A
Ripple Rejection V
CONTROL
= V
POWER
= 3.25V, 60 80 dB
(Note 3) V
RIPPLE
= 1V
P-P
@ 120Hz, I
OUT
= 4A, C
ADJ
= 0.1µF
Thermal Regulation 30ms Pulse, TA = 25¡C 0.002 %/W
V
CONTROL
Dropout Voltage V
POWER
= 2.05V, I
OUT
= 100mA 1.00 1.15 V
(Minimum V
CONTROL-VOUT
)V
POWER
= 2.05V, I
OUT
= 1A 1.00 1.15 V
(Note 4) V
POWER
= 2.05V, I
OUT
= 2.75A 1.00 1.15 V
V
POWER
= 2.05V, I
OUT
= 4A 1.00 1.15 V
V
POWER
= 2.05V, I
OUT
= 7A 1.10 1.25 V
V
POWER
Dropout Voltage V
CONTROL
= 2.75V, I
OUT
= 100mA .10 .15 V
(Minimum V
POWER-VOUT
)V
CONTROL
= 2.75V, I
OUT
= 1A .15 .20 V
(Note 4) V
CONTROL
= 2.75V, I
OUT
= 2.75A .20 .30 V
V
CONTROL
= 2.75V, I
OUT
= 4A .26 .40 V
V
CONTROL
= 2.75V, I
OUT
= 7A .35 .65 V
RMS Output Noise Freq = 10Hz to 10kHz, TA = 25¡C 0.003 %V
OUT
Temperature Stability 0.5 %
Thermal Shutdown (Note 5) 150 180 210 ¡C
Thermal Shutdown Hysteresis 25 ¡C
V
CONTROL
Supply Only V
CONTROL
= 13V, V
POWER
not connected, 50 mA
Output Current V
ADJUST
= V
OUT
= V
SENSE
= 0V
CS5257A-1
Package Pin Description
PACKAGE PIN # PIN SYMBOL FUNCTION
3
Block Diagram
Electrical Characteristics:
0¡C ² TA² 70¡C, 0¡C ² TJ² 150¡C, V
SENSE
= V
OUT
and V
Adj
=
0V unless otherwise specified.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
POWER
Supply Only V
POWER
= 6V, V
CONTROL
not connected, 0.1 1 mA
Output Current V
ADJUST
= V
OUT
= V
SENSE
= 0V
Note 1: The minimum load current is the minimum current required to maintain regulation. Normally the current in the resistor divider used to set
the output voltage is selected to meet the minimum load current requirement.
Note 2: The V
CONTROL
pin current is the drive current required for the output transistor. This current will track output current with roughly a 1:100
ratio. The minimum value is equal to the quiescent current of the device.
Note 3: This parameter is guaranteed by design and is not 100% production tested.
Note 4: Dropout is defined as either the minimum control voltage, (V
CONTROL)
or minimum power voltage (V
POWER
) to output voltage differential
required to maintain 1.5% regulation at a particular load current.
Note 5: This parameter is guaranteed by design, but not parametrically tested in production. However, a 100% thermal shutdown functional test is
performed on each part.
5L TO-220
1V
SENSE
This Kelvin sense pin allows for remote sensing of the output voltage at the
load for improved regulation. It is internally connected to the positive input
of the voltage sensing error amplifier.
2 Adjust This pin is connected to the low side of the internally trimmed 1.5% bandgap
reference voltage and carries a bias current of about 50µA. A resistor divider
from Adj to V
OUT
and from Adj to ground sets the output voltage. Also,
transient response can be improved by adding a small bypass capacitor from
this pin to ground.
3V
OUT
This pin is connected to the emitter of the power pass transistor and provides a regulated voltage capable of sourcing 7A of current.
4V
CONTROL
This is the supply voltage for the regulator control circuitry. For the device
to regulate, this voltage should be between 1V and 1.25V (depending on the
output current) greater than the output voltage. The control pin current will
be about 1% of the output current.
5V
POWER
This is the power input voltage. The pin is physically connected to the collector of the power pass transistor. For the device to regulate, this voltage
should be between 0.1V and 0.65V greater than the output voltage, depending on output current. The output load current of 7A is supplied through
this pin.
V
POWER
V
CONTROL
BIAS
and
TSD
V
REF
-
EA
+
IA
+
-
V
OUT
V
SENSE
Adjust
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