The ZXCL series have been designed with space
sensitive systems in mind. They are available in
the ultra small SC70-5 package, which is half the
size of SOT23 based regulators.
The devices can be used with all types of output
capacitors including low ESR ceramics and
typical dropout voltage, is only 85mV at 50mA
load. Supply current is minimised with a ground
pin current of only 50
Logic control allows the devices to be shut
down, consuming typically less than 10nA.
These features make the device ideal for battery
powered applications where power economy is
critical.
For applications requiring improved
performance over alternative devices, the
ZXCL is also offered in the 5 pin SOT23
package with an industry standard pinout.
The devices feature thermal overload and
over-current protection and are available with
output voltages of 2.5V, 2.6V, 2.8V, 3V, 3.3V.
A at full 150mA load.
Package footprint
SOT23-5 (see P7 for SC70-5)
Package suffix - E5
Features
•Low 85mV dropout at 50mA load
•50
A ground pin current with full 150mA load
•2.5, 2.6, 2.8, 3, & 3.3 volts output
•Very low noise, without bypass capacitor
•5-pin SC70 and SOT23 package
•No-load stable
Applications
•Cellular and Cordless phones
•PDA
•Hand held instruments
•Camera, Camcorder, Personal stereo
•PC cards
•Portable and battery-powered equipment
No-Load Stability
is stable with no external load. e.g. CMOS RAM applacations.
Stresses beyond those listed under “Absolute maximum ratings” may cause permanent damage
to the device. These are stress ratings only, and functional operation of the device at these or any
other conditions beyond those indicated in the operational sections of the specifications is not
implied. Exposure to absolute maximum conditions for extended periods may affect device
reliability.
VIN = VO = 0.5V, all values at TA = 25°C (Unless otherwise stated)
Symbol ParameterConditionsLimitsUnits
Min.Typ.Max.
V
O
⌬V
O
I
O(Max)
I
OLIM
I
O
V
DO
⌬V
LNR
⌬V
LDR
E
N
V
ENHS
I
EN
I
OSD
T
SD
Device testing is performed at TA=25°C. Device thermal performance is guaranteed by design.
Note1: Maximum power dissipation is calculated assuming the device is mounted on a PCB measuring 2 inches square
Note2:Output voltage will start to rise when V
Note3:Dropout voltage is defined as the difference between V
Output voltageIO=1mA-2%+2%V
I
=100mA
O
VO+0.5V < VIN < VIN max
/⌬TOutput voltage
-3%+3%V
-15
temperature
coefficient
Output current150mA
XCL250/5213V25 only100
Over current limit160800mA
XCL250/5213V25 only105230750
Ground pin
current
Dropout voltage
note 3
No Load2550A
I
=150mA50120A
O
=100mA40100A
I
O
IO=10mAAll variants15mV
=50mA85mV
I
O
=100mA ZXCL250 / 5213V25163325mV
I
O
=100mA ZXCL260 / 5213V26155310mV
I
O
=100mA ZXCL280 / 5213V28140280mV
I
O
=100mA ZXCL300 / 5213V30140280mV
I
O
I
=100mA ZXCL330 / 5213V33140280mV
O
=100mA
I
O
ZXCL400 / 5213V40
140280mV
Line regulationVIN=(VO+0.5V) to 5.5V, IO=1mA0.020.1%/V
Load regulationIO=1mA to 100mA0.010.04%/mA
Output noise
f=10Hz to 100kHz, CO=10F50V
voltage
Enable pin
150mV
hysteresis
Enable pin input
VEN=5.5V100nV
current
Shutdown supply
VEN=0V1A
current
Thermal shutdown
125165°C
temperature
exceeds a value or approximately 1.3V. For normal operation,
V
> V
IN(min)
value. Nominal value of V
OUT(nom)
+ 0.5V.
is defined at VIN=VO+0.5V.
O
IN
and VO, when VO has dropped 100mV below its nominal
In common with many other LDO regulators, the
ZXCL device has an inherent diode associated
with the output series pass transistor. This diode
has its anode connected to the output and its
cathode to the input. The internal diode is
normally reverse biased, but will conduct if the
output is forced above the input by more than a
VBE (approximately 0.6V). Current will then flow
from V
maximum current in this diode should be
limited to 5mA continuous and 30mA peak. An
external schottky diode may be used to provide
protection when this condition cannot be
satisfied.
to Vin. For safe operation, the
out
Increased Output current
Any ZXCL series device may be used in
conjunction with an external PNP transistor to
boost the output current capability. In the
application circuit shown below, a FMMT717
device is employed as the external pass
element. This SOT23 device can supply up to
2.5A maximum current subject to the thermal
dissipation limits of the package (625mW).
Alternative devices may be used to supply
higher levels of current. Note that with this
arrangement, the dropout voltage will be
increased by the V
Also, care should be taken to protect the pass
transistor in the event of excessive output
current.
A TTL compatible input is provided to allow the
regulator to be shut down. A low voltage on the
Enable pin puts the device into shutdown mode.
In this mode the regulator circuit is switched off
and the quiescent current reduces to virtually
zero (typically less than 10nA) for input voltages
above the minimum operating threshold of the
device. A high voltage on the Enable pin ensures
normal operation.
ZXCL SERIES
R
C
The Enable pin can be connected to V
IN
or
driven from an independent source of up to 10V
maximum. (e.g. CMOS logic) for normal
operation. There is no clamp diode from the
Enable pin to V
, so the VIN pin may be at any
IN
voltage within its operating range irrespective
of the voltage on the Enable pin. However input
voltage rise time should be kept below 5ms to
ensure consistent start-up response.
Current Limit
The ZXCL devices include a current limit circuit
which restricts the maximum output current
flow to typically 230mA. Practically the range of
over-current should be considered as minimum
160mA to maximum 800mA. The device’s
robust design means that an output short circuit
to any voltage between ground and V
OUT
can be
tolerated for an indefinite period.
Thermal Overload
Thermal overload protection is included on
chip. When the device junction temperature
exceeds a minimum 125°C the device will shut
down. The sense circuit will re-activate the
output as the device cools. It will then cycle until
the overload is removed. The thermal overload
protection will be activated when high load
currents or high input to output voltage
differentials cause excess dissipation in the
device.
Figure 1 Circuit Connection
Figure 2 Start up delay (T
d
)
Start up delay
A small amount of hysteresis is provided on the
Enable pin to ensure clean switching. This
feature can be used to introduce a start up delay
if required. Addition of a simple RC network on
the Enable pin provides this function. The
following diagram illustrates this circuit
connection. The equation provided enables
calculation of the delay period.
The maximum allowable power dissipation of
the device for normal operation (P
function of the package junction to ambient
thermal resistance (
temperature (Tj
(T
), according to the expression:
amb
P
max
= (Tj
max
– T
The maximum output current (I
value of Input voltage (V
(V
) is then given by
OUT
θja), maximum junction
), and ambient temperature
max
) /
θ
amb
ja
max
) and output voltage
IN
), is a
max
) at a given
ZXCL SERIES
The dielectric of the ceramic capacitance is an
important consideration for the ZXCL Series
operation over temperature. Zetex recommends
minimum dielectric specification of X7R for the
input and output capacitors. For example a
ceramic capacitor with X7R dielectric will lose 20%
of its capacitance over a -40
range, whereas a capacitor with a Y5V dielectric
loses 80% of its capacitance at -40
85
⬚
C.
An input capacitor of 1
recommended to filter supply noise at the device
input and will improve ripple rejection.
⬚
C to 85⬚C temperature
⬚
C and 75% at
F (ceramic or tantalum) is
I
max
= P
/ (VIN - V
max
OUT
)
The value of qja is strongly dependent upon the
type of PC board used. Using the SC70 package
it will range from approximately 280°C/W for a
multi-layer board to around 450°C/W for a single
sided board. It will range from 180°C/W to
300°C/W for the SOT23-5 package. To avoid
entering the thermal shutdo wn state, Tjmax
should be assumed to be 125°C and Imax less
than the over-current limit,(I
OLIM
). Power
derating for the SC70 and SOT23-5 packages is
shown in the following graph.
Capacitor selection and regulator stability
The device is designed to operate with all types
of output capacitor, including tantalum and low
ESR ceramic. For stability over the full operating
range from no load to maximum load, an output
capacitor with a minimum value of 1
μ
F is
recommended, although this can be increased
without limit to improve load transient
performance. Higher values of output capacitor
will also reduce output noise. Capacitors with
ESR less than 0.5V are recommended for best
results.
The input and output capacitors should be
positioned close to the device, and a ground plane
board layout should be used to minimise the
effects of parasitic track resistance.
Dropout voltage
The output pass transistor is a large PMOS device,
which acts like a resistor when the regulator enters
the dropout region. The dropout voltage is
therefore proportional to output current as shown
in the typical characteristics.
Ground current
The use of a PMOS device ensures a low value of
ground current under all conditions including
dropout, start-up and maximum load.
Power supply rejection and load transient
response
Line and Load transient response graphs are
shown in the typical characteristics.
These show both the DC and dynamic shift in the
output voltage with step changes of input voltage
and load current, and how this is affected by the
output capacitor.
If improved transient response is required, then an
output capacitor with lower ESR value should be
used. Larger capacitors will reduce over/
undershoot, but will increase the settling time.
Best results are obtained using a ground plane
layout to minimise board parasitics.
Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or
service. Customers are solely responsible for obtaining the latest relevant information before placing orders.
Applications disclaimer
The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for
the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoever is
assumed by Zetex with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights
arising from such use or otherwise. Zetex does not assume any legal responsibility or will not be held legally liable (whether in contract,
tort (including negligence), breach of statutory duty, restriction or otherwise) for any damages, loss of profit, business, contract,
opportunity or consequential loss in the use of these circuit applications, under any circumstances.
Life support
Zetex products are specifically not authorized for use as critical components in life support devices or systems without the express written
approval of the Chief Executive Officer of Zetex Semiconductors plc. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body
or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labelling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to
cause the failure of the life support device or to affect its safety or effectiveness.
Reproduction
The product specifications contained in this publication are issued to provide outline information only which (unless agreed by the
company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a
representation relating to the products or services concerned.
Terms and Conditions
All products are sold subjects to Zetex’ terms and conditions of sale, and this disclaimer (save in the event of a conflict between the two
when the terms of the contract shall prevail) according to region, supplied at the time of order acknowledgement.
For the latest information on technology, delivery terms and conditions and prices, please contact your nearest Zetex sales office.
Quality of product
Zetex is an ISO 9001 and TS16949 certified semiconductor manufacturer.
To ensure quality of service and products we strongly advise the purchase of parts directly from Zetex Semiconductors or one of our
regionally authorized distributors. For a complete listing of authorized distributors please visit: www.zetex.com/salesnetwork
Zetex Semiconductors does not warrant or accept any liability whatsoever in respect of any parts purchased through unauthorized sales channels.
ESD(Electrostatic discharge)
Semiconductor devices are susceptible to damage by ESD. Suitable precautions should be taken when handling and transporting devices.
The possible damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. The extent
of damage can vary from immediate functional or parametric malfunction to degradation of function or performance in use over time.
Devices suspected of being affected should be replaced.
Green compliance
Zetex Semiconductors is committed to environmental excellence in all aspects of its operations which includes meeting or exceeding
regulatory requirements with respect to the use of hazardous substances. Numerous successful programs have been implemented to
reduce the use of hazardous substances and/or emissions.
All Zetex components are compliant with the RoHS directive, and through this it is supporting its customers in their compliance with
WEEE and ELV directives.
Product status key:
“Preview”Future device intended for production at some point. Samples may be available
“Active”Product status recommended for new designs
“Last time buy (LTB)”Device will be discontinued and last time buy period and delivery is in effect
“Not recommended for new designs”
“Obsolete”Production has been discontinued
Datasheet status key:
“Draft version”This term denotes a very early datasheet version and contains highly provisional information, which
“Provisional version”This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance.
“Issue”This term denotes an issued datasheet containing finalized specifications. However, changes to