MIC5271 - Micrel

MIC5271
µC
Cap Negatiive Low-Drropout Reg
gulator
Gen
neral Desc
cription
Featu
ures
The MIC5271 is a µCap 100mA negative
e regulator in a
ge. With bette
er than 2% initial accurac
cy,
SOT--23-5 packag
this rregulator prov
vides a very accurate sup
pply voltage for
f
applications that require a negative
n
rail. The MIC5271
d
voltage
sinkss 100mA of output current at very low dropout
(600m
mV maximum
m at 100mA off output curre
ent).









The µCap regulattor design is optimized to work with lowe, low-cost ceramic
c
capa
acitors. The output
o
typica
ally
value
requiires only a 1µ
µF capacitanc
ce for stability.
Desig
gned for ap
pplications wh
here small packaging
p
and
efficie
ency are critiical, the MIC5
5271 combines LDO design
expe
ertise with IttyBitty® packag
ging to improv
ve performance
and rreduce powerr dissipation. Ground curre
ent is optimized
to he
elp improve battery
b
life in
n portable ap
pplications. The
MIC5
5271 also in
ncludes a TTL-compatib
T
le enable pin,
allow
wing the userr to put the part into a zero-current
z
off
mode
e.
The MIC5271 is available
a
in the 5-pin SOT--23 package for
f
pplications an
nd it is ava
ailable with an
space saving ap
adjusstable output.
Stab
ble with ceram
mic or tantalum capacitor
Pos itive and negative enable tthresholds
Low
w dropout volta
age: 500mV
V @ 100mA
Low
w ground curre
ent: 25µA @ load = 100
0µA
Tigh
ht initial accurracy: ±2%
Tigh
ht load and lin
ne regulation
The rmal shutdow
wn and curren
nt-limit protecttion
IttyB
Bitty 5-pin SO
OT-23 packaging
Zero
o-current off m
mode
Appllications





GaA
AsFET bias
Porttable camerass and video re
ecorders
PDA
As
Batttery-powered equipment
Postt-regulation o
of DC-to-DC cconverters
Datasheets and support
s
docu
umentation arre available on
el’s web site at:
a www.micre
el.com.
Micre
Typ
pical Application
Regulator wiith Adjustable
e Negative Voltage Output
IttyBitty is a registere
ed trademark of Micrel,
M
Inc.
Micrel Inc. • 2180 Fortune Driv
ve • San Jose, CA
C 95131 • USA • tel +1 (408) 94
44-0800 • fax + 1 (408) 474-1000
0 • http://www.m
micrel.com
April 6
6, 2015
04
40615-2.0 (whille in progress)
R
Revision 2.0 (fin
nal document)
Micrel, Inc.
MIC5271
Ordering Information
(1)
(2)
Part Number
Marking
Voltage
Junction Temperature Range
Package
MIC5271YM5
L9AA
Adjustable
–40°C to +125°C
SOT-23-5
MIC5271-3.0YM5
L930
–3.0V
–40°C to +125°C
SOT-23-5
MIC5271-5.0YM5
L950
–5.0V
–40°C to +125°C
SOT-23-5
Note:
1. Other voltages are available. Contact Micrel for details.
2. Underbar (_) symbol may not be to scale.
Pin Configurations
MIC5271YM5
Adjustable Output Voltage
(Top View)
MIC5271-3.0YM5
Fixed Output Voltage
(Top View)
MIC5271-5.0YM5
Fixed Output Voltage
(Top View)
Pin Description
MIC5271YM5
MIC5271-3.0YM5
MIC5271-5.0YM5
Pin Name
Pin Name
Pin Name
1
EN
EN
EN
2
GND
GND
GND
ADJ
−
−
−
NC
NC
4
−OUT
−OUT
−OUT
5
−IN
−IN
−IN
Pin Number
3
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2
Pin Function
Enable Input. TTL logic-compatible enable input. Logic
HIGH = ON, Logic LOW or open = OFF.
Ground
Adjustable (Input): Adjustable feedback output
connects to resistor voltage divider.
No Connect. Leave unconnected.
Negative Regulator Output.
Negative Supply Input.
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MIC5271
Absolute Maximum Ratings(3)
Operating Ratings(4)
Input Voltage (V-IN) ........................................ −20V to +0.3V
Enable Voltage (VEN). ..................................... −20V to +20V
Power Dissipation (PD) .............................. Internally Limited
Junction Temperature (TJ) ........................ –40°C to +125°C
Lead Temperature (soldering, 10s) ............................ 260°C
Storage Temperature (TS) ......................... –65°C to +150°C
ESD Rating.................................................................Note 6
Input Voltage (V-IN) ........................................ –16V to –3.3V
Enable Voltage (VEN). ..................................... −16V to +16V
Junction Temperature (TJ) ........................ –40°C to +125°C
(5)
Thermal Resistance (θJA) .................................... 235°C/W
Electrical Characteristics(7)
V-IN = V-OUT – 1.0V; COUT = 4.7µF, IOUT = 100µA; TJ = +25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless otherwise noted.
Symbol
Parameter
Condition
V-OUT
Output Voltage Accuracy
Variation from nominal V-OUT
∆V-OUT/∆T
Output Voltage Temperature Coefficient
Note 8
100
∆V-OUT/V-OUT
Line Regulation
V-IN = V-OUT – 1V to –16V
0.04
∆V-OUT/V-OUT
Load Regulation
IOUT = −100µA to −100mA,
Note 9
0.4
IOUT = −100µA
-55
IOUT = −50mA
-360
V-IN − V-OUT
IGND
Dropout Voltage, Note 10
Ground Current, Note 11
Min.
Typ.
Max.
−2
+2
−3
+3
0.15
0.2
1.8
2.0
−500
−700
-500
IOUT = −100µA
-25
IOUT = −50mA
-0.9
IOUT = −100mA
-2.0
-3.0
0.1
+1.0
−1.0
Ground Current in Shutdown
VEN = ±0.6V
PSRR
Ripple Rejection
f = 120Hz
50
ILIMIT
Current Limit
V-OUT = 0V
235
%
ppm/°C
IOUT = −100mA
IGND_SD
Units
%/V
%
mV
−900
−100
µA
mA
µA
dB
350
mA
Notes:
3. Exceeding the absolute maximum ratings may damage the device.
4. The device is not guaranteed to function outside its operating ratings.
5. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max) the junction-to-ambient thermal resistance, θJA,
and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (TJ(max) – TA)
÷ θJA, where θJA is 235°C/W. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go
into thermal shutdown. See the “Thermal Considerations” sub-section in the Application Information for details.
6. Devices are ESD sensitive. Handling precautions are recommended.
7. Specification for packaged product only.
8. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
9. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range
from 100µA to 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
10. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential.
11. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the load
current plus the ground pin current.
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MIC5271
Electrical Characteristics(7) (Continued)
V-IN = V-OUT – 1.0V; COUT = 4.7µF, IOUT = 100µA; TJ = +25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless otherwise noted.
Symbol
Parameter
Condition
TON
Turn-On Time
Time to VOUT = 90% (nominal)
Input Low Voltage
Regulator OFF
Input high Voltage
Regulator ON
VEN
IEN
April 6, 2015
Enable Input Current
Min.
Typ.
60
±2.0
0.1
4
5.6
Units
µs
±0.6
VEN = ± 0.6V and –2.0V
VEN = +2.0V
Max.
10.0
V
µA
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MIC5271
Typical Characteristics
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MIC5271
Typical Characteristics (Continued)
April 6, 2015
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MIC5271
Functional Characteristics
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MIC5271
Functional Diagrams
Figure 1. MIC5271YM5 (Adjustable Voltage)
Figure 2. MIC5271-xxYM5 (Fixed Voltage)
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MIC5271
Application Information
The MIC5271 is a general-purpose negative voltage
regulator that can be used in a system that requires a
clean negative voltage. This includes the post regulation
of DC-to-DC converters (transformer or charge pump
based voltage converters). These negative voltages
typically require a negative low dropout voltage regulator
to provide a clean output from noisy input power.
Input Capacitor
A 1µF input capacitor should be placed from −IN to GND
if there is more than two inches of wire or trace between
the input and the AC filter capacitor or if a battery is used
as the input.
Figure 3. Positive and Negative Enable Voltage vs. Supply
Voltage
Output Capacitor
The MIC5271 requires an output capacitor for stable
operation. A minimum of 1µF of output capacitance is
required. The output capacitor can be increased without
limitation to improve transient response. The output does
not require ESR to maintain stability; therefore a ceramic
capacitor can be used. High-ESR capacitors may cause
instability. Capacitors with an ESR of 3Ω or greater at
100kHz can cause a high-frequency oscillation.
Thermal Considerations
Absolute values will be used for thermal calculations to
clarify the meaning of power dissipation and voltage
drops across the part.
Proper thermal design for the MIC5271-5.0YM5 can be
accomplished with some basic design criteria and some
simple equations. The following information must be
known to implement your regulator design:
Low-ESR tantalums are recommended due to the tight
capacitance tolerance over temperature. The Z5U
dielectric can change capacitance value by as much 50%
over temperature, and the Y5V dielectric can change
capacitance value by as much as 60% over temperature.
To use a ceramic chip capacitor with the Y5V dielectric,
the value must be much higher than a tantalum to ensure
the same minimum capacitor value over temperature.
•
•
•
•
•
No-Load Stability
The MIC5271 does not require a load for stability.
VIN = Input voltage
VOUT = Output voltage
IOUT = Output current
TA = Ambient operating temperature
IGND = Ground current
Maximum power dissipation can be determined by
knowing the ambient temperature (TA), the maximum
junction temperature (+125°C), and the thermal
resistance (junction-to-ambient). The thermal resistance
for this part, assuming a minimum footprint board layout,
is +235°C/W. The maximum power dissipation at an
ambient temperature of +25°C can be determined with
Equations 1 and 2:
Enable Input
The MIC5271 comes with an enable pin that allows the
regulator to be disabled. Forcing the enable pin higher
than the negative threshold and lower than the positive
threshold disables the regulator and sends it into a “zero”
off-mode current state. In this state, current consumed by
the regulator goes nearly to zero. The MIC5271 will be in
the “on” mode when the voltage applied to the enable pin
is either greater than the positive threshold or less than
the negative threshold.
PD(MAX ) =
TJ(MAX ) − TA
θ JA
Eq. 1
PD(MAX ) =
125°C − 25°C
235°C / W
Eq. 2
Where PD(MAX) = +425mW.
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MIC5271
Adjustable Regulator Application
The actual power dissipation of the regulator circuit can
be determined using Equation 3:
PD = (VIN – VOUT) × IOUT + (VIN × IGND)
The MIC5271YM5 can be adjusted from −1.20V to −14V
by using two external resistors (Figure 4). The resistors
set the output voltage based on Equation 4.
Eq. 3
Substituting PD(MAX), determined above, for PD and solving
for the operating conditions that are critical to the
application will give the maximum operating conditions for
the regulator circuit. The maximum power dissipation
number cannot be exceeded for proper operation of the
device. The maximum input voltage can be determined
using the output voltage of 5.0V and an output current of
100mA. Ground current, of 2mA for 100mA of output
current, can be taken from the Electrical Characteristics.
•
•
•
•
425mW = (VIN − 5.0V)100mA + VIN × 2mA
425mW = (100mA × VIN + 2mA × VIN) −500mW
925mW = 102mA × VIN
VIN = 9.07V (maximum)
Figure 4. Adjustable Voltage Application
Therefore, a –5.0V application at -100mA of output
current can accept a maximum input voltage of –9.07V in
a SOT-23 package. For a full discussion of heat sinking
and thermal effects on voltage regulators, refer to
“Regulator Thermals” section of Micrel’s Designing with
Low Dropout Voltage Regulators handbook.
April 6, 2015
 R2 
VOUT = VREF  1 +

R1 

Eq. 4
Where VREF = 1.20V.
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MIC5271
Package Information and Recommended Landing Pattern(12)
5-Pin SOT-23 (M5)
Note:
12. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com.
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MIC5271
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications
markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock
management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company
customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products.
Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and
advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network
of distributors and reps worldwide.
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical
implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2003 Micrel, Incorporated.
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