Features
Package Options
CS5253-1
3A LDO 5-Pin Adjustable Linear Regulator
CS5253-1
Description
Applications Diagram
1
5 Lead D
2
PAK
1
1. V
SENSE
2. Adjust
3. V
OUT
4. V
CONTROL
5. V
POWER
Tab = V
OUT
Rev. 5/6/99
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
V
SENSE
V
OUT
V
CONTROL
V
POWER
CS5253-1
2.5V @ 3A
300
mF
5V
Load
124
1%
124
1%
0.1
mF
5V
100
mF
5V
10
mF
10V
3.3V
5.0V
Adjust
This new very low dropout regula-
tor is designed to power the next
generation of advanced micropro-
cessors. To achieve very low
dropout, the internal pass transistor
is powered separately from the con-
trol 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 mini-
mum control voltage.
It is supplied in a five-terminal
D
2
PAK package, which allows for
the implementation of a remote-
sense pin permitting very accurate
regulation of output voltage direct-
ly at the load, where it counts,
rather than at the regulator. This
remote sensing feature virtually
eliminates output voltage varia-
tions due to load changes and resis-
tive voltage drops. Typical load
regulation measured at the sense
pin is less than 1mV for an output
voltage of 2.5V with a load step of
10mA to 3A.
The very fast transient loop
response easily meets the needs of
the latest microprocessors. In addi-
tion, a small capacitor on the Adjust
pin will further improve the tran-
sient capabilities.
Internal protection circuitry pro-
vides for bust-proof operation,
similar to three-terminal regulators.
This circuitry, which includes over-
current, short circuit, and over-tem-
perature protection will self protect
the regulator under all fault condi-
tions.
The CS5253-1 is ideal for generating
a secondary 2-2.5V low voltage
supply on a motherboard where
both 5V and 3.3V are already avail-
able.
s
1.25V to 5V V
OUT
at 3A
s
V
POWER
Dropout < 0.40V @ 3A
s
V
CONTROL
Dropout < 1.05V @
3A
s
1% Trimmed Reference
s
Fast Transient Response
s
Remote Voltage Sensing
s
Thermal Shutdown
s
Current Limit
s
Short Circuit Protection
s
Drop-In Replacement for
Semtech EZ1582
s
Backwards Compatible with
3-pin Regulators
Electrical Characteristics:
0CT
A
70C, 0CT
J
150C, V
SENSE
= V
OUT
and V
Adj
= 0V unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CS5253-1
2
Absolute Maximum Ratings
V
POWER
Input Voltage.......................................................................................................................................................................6V
V
CONTROL
Input Voltage.................................................................................................................................................................13V
Operating Junction Temperature Range ................................................................................................................0C T
J
150C
Storage Temperature Range .....................................................................................................................................-65C to +150C
Lead Temperature Soldering
Reflow (SMD styles only) ......................................................................................60 sec. max above 183C, 230C peak
ESD Damage Threshold............................................................................................................................................................2kV
Reference Voltage
V
CONTROL
=2.75V to 12V,
1.237
1.250
1.263
V
V
POWER
=2.05V to 5.5V, I
OUT
= 10mA to 3A
(-1%)
(+1%)
Line Regulation
V
CONTROL
= 2.5V to 12V,
.02
.20
%
V
POWER
= 1.75V to 5.5V, I
OUT
= 10mA
Load Regulation
V
CONTROL
= 2.75V,
.04
.30
%
V
POWER
= 2.05V, I
OUT
= 10mA to 3A,
with remote sense
Minimum Load Current
V
CONTROL
= 5V, V
POWER
= 3.3V,
5
10
mA
(Note 1)
V
OUT
= +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
= 3A
35
120
mA
Adjust Pin Current
V
CONTROL
=2.75V, V
POWER
= 2.05V, I
OUT
= 10mA
60
120
A
Current Limit
V
CONTROL
= 2.75V, V
POWER
= 2.05V,
3.1
4.0
A
V
OUT
= -1%
Short Circuit Current
V
CONTROL
= 2.75V, V
POWER
= 2.05V, V
OUT
= 0V
2.6
3.5
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
= 0.1F
Thermal Regulation
30ms Pulse, T
A
=25C
0.002
%/W
V
CONTROL
Dropout Voltage
V
POWER
= 2.05V, I
OUT
= 100mA
0.90
1.15
V
(Minimum V
CONTROL
-V
OUT
)
V
POWER
= 2.05V, I
OUT
= 1A
1.00
1.15
V
(Note 4)
V
POWER
= 2.05V, I
OUT
= 3A
1.05
1.30
V
V
POWER
Dropout Voltage
V
CONTROL
= 2.75V, I
OUT
= 100mA
.05
.15
V
(Minimum V
POWER
-V
OUT
)
V
CONTROL
= 2.75V, I
OUT
= 1A
.15
.25
V
(Note 4)
V
CONTROL
= 2.75V, I
OUT
= 3A
.40
.60
V
RMS Output Noise
Freq = 10Hz to 10kHz, T
A
= 25C
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
V
POWER
Supply Only
V
POWER
= 6V, V
CONTROL
not connected,
0.1
1.0
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% 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.
CS5253-1
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
3
Block Diagram
V
CONTROL
BIAS
and
TSD
V
REF
EA
IA
V
OUT
V
SENSE
Adjust
-
+
-
+
V
POWER
5Lead D
2
PAK
1
V
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% bandgap reference voltage and carries a bias current of
about 50A. 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.
3
V
OUT
This pin is connected to the emitter of the power pass transistor
and provides a regulated voltage capable of sourcing 3A of
current.
4
V
CONTROL
This is the supply voltage for the regulator control circuitry. For
the device to regulate, this voltage should be between 0.9V and
1.3V (depending on the output current) greater than the
output voltage. The control pin current will be about 1% of the
output current.
5
V
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 0.6V greater
than the output voltage, depending on output current. The out-
put load current of 3A is supplied through this pin.
CS5253-1
4
Typical Performance Characteristics
0
20
40
60
80
100
120
Reference V
oltage (V)
Junction Temperature (C)
1.247
1.248
1.249
1.250
1.251
1.252
1.253
Reference Voltage vs Junction Temperature
V
OUT
I
LOAD
,
10mA to 3A
V
CONTROL
= 5.0V
V
POWER
= 3.3V
V
OUT
= 2.5V
C
CONTROL
= 10mF
C
POWER
= 100
mF
C
ADJ
= 0.1
mF
C
OUT
= 300
mF
Transient Response
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
1
2
3
4
5
6
V
POWER
- V
OUT
(V)
Output Current (A)
Measured at
DV
OUT
= -1%
Output Current vs V
POWER
-V
OUT
I
ADJ
(
m
A)
Junction Temperature (C)
0
20
40
60
80
100
120
140
60
65
70
75
80
85
Adjust Pin Current vs Junction Temperature
1.0
3.0
4.0
5.0
6.0
7.0
800
Minimum Load Current (
m
A)
V
CONTROL
-V
OUT
(V)
9.0
10.0
11.0
2.0
8.0
850
900
950
1000
1050
1100
1150
1200
V
POWER
=3.3V
D V
OUT
=+1%
Minimum Load Current vs V
CONTROL
-V
OUT
0.5
1.0
1.5
2.0
2.5
Output Current (A)
T
J
= 120
C
T
J
= 20
C
0
3.0
0.08
0.10
0.12
0
0.02
0.04
0.06
Load Regulation (%)
T
J
= 0
C
Load Regulation vs Output Current
CS5253-1
5
Typical Performance Characteristics
10.0
10
1
Frequency (Hz)
Ripple Rejection (dB)
20.0
30.0
40.00
60.0
70.0
80.0
90.0
10
2
10
3
10
4
10
6
10
5
50.0
V
IN
-V
OUT
=2V
I
OUT
=4A
V
RIPPLE
=1V
P-P
C
OUT
=22
mF
C
ADJ
=0.1
mF
Ripple Rejection vs Frequency
Short Circuit Output Current Limit (A)
3.3
3.4
3.5
3.6
3.7
3.8
3.9
0
20
40
60
80
100
120
140
Junction Temperature (C)
V
POWER
= 2.05V
V
CONTROL
= 2.75V
Short Circuit Output Current vs Junction Temperature
Vpower Dropout V
oltage (V)
0
0.0
Output Current (A)
50
150
200
250
300
350
400
450
500
0.5
1.0
3.0
2.5
2.0
1.5
T
J
= 120
C
T
J
= 20
C
T
J
= 0
C
V
POWER
Dropout Voltage vs Output Current
0
2
4
6
8
10
12
0
20
40
60
80
100
120
140
Junction Temperature (C)
Iout (mA)
V
CONTROL
= 13V,
V
OUT
= 0V,
Vpower not connected
Vcontrol Dropout V
oltage (mV)
0.0
Output Current (A)
800
900
1000
1100
0.5
1.0
3.0
2.5
2.0
1.5
T
J
= 120
C
T
J
= 20
C
T
J
= 0
C
V
POWER
= 2.05V
V
CONTROL
Dropout Voltage vs Output Current
V
CONTROL
Only Output Current vs Junction Temperature
0.50
1.50
2.50
915.5
Minimum Load Current (
m
A)
V
POWER
-V
OUT
(V)
3.50
4.50
915.6
915.7
915.8
915.9
916.0
916.1
916.2
916.4
V
CONTROL
=5V
D V
OUT
=+1%
915.4
916.3
Minimum Load Current vs V
POWER
-V
OUT
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