TS2951/A
150mA Ultra Low Dropout Voltage Regulator
SOP-8
Pin Definition:
1. Output
8. Input
2. Sense
3. Shutdown
4. Ground
7. FB
6. Voltage tap
5. Error flag
General Description
The TS2951/A are low power voltage regulators. These devices are excellent choice for use in battery-powered
applications such as cordless telephone, radio control systems, and portable computers.
The TS2951/A is features very low quiescent current (75uA Typ.) and very low drop output voltage (Typ. 40uV at
light load and 380 mV at 100 mA). This includes a tight initial tolerance of 1% (A version), extremely good load
and line regulation 0.05% typ. and very low output temperature coefficient, making the TS2951/A useful as a
low-power voltage reference.
TS2951/A have other key additional feature. The error flag output feature is used as power-on reset for warn of a
low output voltage, due to following batteries on input. The logic-compatible shutdown input which enable the
regulator to be switched on/off. The regulator output voltage may be pin-strapped for a 5.0 & 3.3 & 3.0 of
programmed from 1.24V to 29V with external pair of resistors. Using of as design, processing and testing
techniques make TS2951/A superior over similar products.
Features
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Output voltage available in 5V & 3.3V
Extremely low quiescent current
Low dropout voltage
Extremely tight load and line regulation
Very low temperature coefficient
Need only 1uF for stability
Use as Regulator or Reference
Stable with low-ESR output capacitors
Current and thermal limiting
Error Flag warns of output dropout
Logic-Controlled electronic shutdown
Additional voltage tap
Output voltage sense
Output programmable from 1.24 to 29V
Ordering Information
Part No.
TS2951CSxx RL
TS2951ACSxx RL
Package
SOP-8
SOP-8
Packing
2.5Kpcs / 13” Reel
2.5Kpcs / 13” Reel
Note: Where
xx
denotes voltage option, available are
50=
5.0V
33=
3.3V
30=
3.0V
Application
●
●
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Battery powered systems
SMPS Post-Regulator
Voltage Reference
Portable consumer equipment
Absolute Maximum Rating
Parameter
Input Supply Voltage
Feedback Input Voltage
Shutdown Input Voltage
Error Comparator Output Voltage
Power Dissipation
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering 5 second)
Thermal Resistance Junction to Ambient
Thermal Resistance Junction to Case
1/10
Symbol
V
IN
Vfeedback
Vshutdown
Verror
Pd
T
J
T
STG
T
STG
RӨ
JA
RӨ
JC
Limit
- 0.3 ~ +30
- 1.5 ~ +30
- 0.3 ~ +30
- 0.3 ~ +30
Internally Limited
- 40 ~ +125
-65 ~ +150
260
180
45
Unit
V
V
V
V
W
o
o
o
o
o
C
C
C
C/W
C/W
Version: D11
TS2951/A
150mA Ultra Low Dropout Voltage Regulator
Electrical Characteristics
(V
IN
=V
OUT
+1V, Ta=25
o
C, unless otherwise specified.)
Parameter
Test Conditions (note 2)
Tj=25 C
Output Voltage
Full Operating temp
100uA≤ I
L
≤100mA
Tj≤Tj(max)
Output Voltage Temperature
Coefficient
Line Regulation (Note 3)
Load Regulation (Note 3)
Dropout Voltage (Note 5)
Ground Current
Dropout Ground Current
Current Limit
Thermal Regulation
Output Noise, 10Hz to 100KHz
Bypass=0.01uF
(pins 7 to 1 TS2951/A)
Reference Voltage
Feedback Pin Bias Current
Reference Voltage Temperature
Coefficient
Feedback Pin Bias Current
Temperature Coefficient
Output Leakage Current
Output Low Voltage
Upper Threshold Voltage
Power Threshold Voltage
Hysteresis
Output Logic Voltage
Shut down Pin Current
Regulator Output Current in
Shutdown
V
OH
= 30V
V
IN
= 4.5V, I
OL
= 400uA
(Note 8)
(Note 8)
(Note 8)
Low (Regulator ON)
High(Regulator OFF)
Vs = 2.4V
Vs = 30V
(Note 9)
(Note 7)
C
L
= 1uF
C
L
= 200uF
C
L
= 3.3uF
(Note6)
TS2951
TS2951A
(Note 1)
6V≤ V
IN
≤30V
(Note 4)
100uA≤ I
L
≤100mA
I
L
=100uA
I
L
=100mA
I
L
=100uA
I
L
=100mA
V
IN
= 4.5V, I
L
= 100uA
V
OUT
= 0
o
Min
|0.985|
|0.990|
|0.980|
|0.988|
|0.975|
|0.985|
--
--
--
--
--
--
--
--
--
--
--
--
1.185
1.19
--
--
--
--
--
40
--
--
--
2.0
--
--
Typ
Max
|1.015|
|1.010|
|1.020|
|1.012|
|1.025|
|1.015|
150
100
0.2
0.3
80
450
120
12
170
200
0.2
--
--
--
1.285
1.27
40
--
--
1
250
--
95
--
0.7
--
50
600
10
Unit
TS2951
TS2951A
TS2951
TS2951A
TS2951
TS2951A
TS2951
TS2951A
5.0
3.3
3.0
V
50
20
0.04
0.1
50
380
75
8
110
160
0.05
430
160
100
1.235
20
20
0.1
0.01
150
60
75
15
1.3
1.3
30
450
3
ppm/
o
C
%
%
mV
mV
uA
mA
uA
mA
%W
uV/
rms
V
nA
ppm/
o
C
o
nA/ C
uA
mV
mV
mV
mV
V
uA
uA
2/10
Version: D11
TS2951/A
150mA Ultra Low Dropout Voltage Regulator
NOTE:
1:
Output voltage temperature coefficients defined as the worst case voltage change divided by the total
temperature range.
2:
Unless otherwise specified all limits guaranteed for T
j
= 25 C, Vin= 6V, I
L
= 100uA and C
L
= 100uF. Additional
conditions for the 8-pin versions are feedback tied to 5V, 3.3V & 3V tap output Sense (Vout = 5V, 3.3V & 3V) and
shutdown
≤
0.8V.
3:
Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in
output voltage due to heating effects are covered under the specification for thermal regulation.
4:
Line regulation for the TS2951 is tested at 85 C for I
L
= 1mA.For I
L
= 100uA and Tj= 125 C, line regulation is
guaranteed by design to 0.2%.
5:
Dropout Voltage is defined as the input to output differential at which the output voltage drops 100mV below its
nominal value measured at 1V differential at very low value of programmed output voltage, the minimum input
supply voltage of 2V (2.3V over temperature) must be taken in to account.
6:
Vref
≤
Vout
≤
(Vin-1V), 2.3≤ Vin≤ 30V, 100uA≤ I
L
≤
100mA, Tj
≤
Tj(max)
.
7:
Reference voltage temperature coefficient is defined as the worst case voltage change divided by the total
temperature range.
8:
Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the
nominal reference voltage measured at 6V input. To express these thresholds in terms of output voltage change,
multiply by the error amplifier gain= Vout / Vref = (R1+R2) / R2. For example, at a programmed output voltage of
5V, the Error output is guaranteed to go low when the output drops by 95 mV X 5V / 1.250 = 384mV. Thresholds
remain constant as a percent of Vout as Vout is varied with the dropout warning occurring at typically 5% below
nominal, 7.5% guaranteed.
o
o
o
Application Hints
External Capacitors
For the stability of the TS2951/A is requires a 1.0uF(0.22uF is recommended for 3.0V & 3.3V) or greater capacitor
between output and ground. Oscillation could occur without this capacitor. The tantalum or aluminum electrolytic
o
works fine; could use the film type work but are not cost efficient. For the operation of below -25 C solid tantalum is
o
recommended since the many aluminum type have electrolytes the freeze at about -30 C. The ESR of about 5 or
less and resonant frequency above 500KHz are most important parameter in the value of Capacitor. The
Capacitors value can be increased without any limit. At lower values of output current, less output capacitance is
required for stability. For the currents below 10mA the value of capacitor can be reduce to 0.33uF and 0.1uF for
1mA. More output capacitance needed for the 8-pin version at voltage below 5V since it runs the error amplifier at
lower gain. At worst case 3.3uF or greater must be used for condition of 100mA load at 1.250V output.
The TS2951/A is not like other low dropout regulators will remain stable and regulation with no load in addition to
the internal voltage divider. This feature very important in application, it is like CMOS RAM keep-alive. The
TS2951/A output voltage is set with minimum load of 1uA and external resistors.
If at the input ofTS2951/A connected to battery or between AC filter capacitor and input is 10 inches wire then 1uF
tantalum or aluminum electrolytic capacitor should be connected between input and ground. Instability can occur if
stray capacitor to feedback terminal pin 7 of the TS2951/A. This could cause more problems when using higher
value of external to set the output voltage. To fix this problem the 100pF capacitor between output and feedback
and increasing output capacitance to 3.3uF.
3/10
Version: D11
TS2951/A
150mA Ultra Low Dropout Voltage Regulator
Application Hints
(continued)
Reducing Output Noise
It could be an advantage to reduce the AC noise present at the output. One method is to reduce the regulator
bandwidth by increasing the value of the output capacitor. This is the only method that noise could reduce on the
TS2951/A, but is relatively inefficient, as increasing capacitor from 1uF to 220uF only decreases the noise from
430uV to 160uVrms for a 100KHz bandwidth at 5V output. Noise could be also reduced by fourfold by a bypass
capacitor across R1 since it reduces the high frequency gain from 4 to unity.
Pick Cbypass= 1 / 2πR1 * 200Hz or choose 0.01uF when doing this, the output capacitor must be increased to
3.3uF to maintain stability. These change the output noise from 430uV/rms for a 100 kHz bandwidth 5V, 3.3V & 3V
output. With the bypass capacitor added, noise no longer scales with output voltage so that improvements are
more dramatic higher output voltage.
Error Detection Comparator Output
The Compactor produces a logic low output whenever the TS2951/A output falls of regulation by more than around
5%. This is around 60 mV offset divided by the 1.235 reference voltage. Thus trip remains 5% below nominal
regardless of the programmed output voltage of the regulator. The Figure 1 shows the timing diagram depicting the
ERROR signal and the regulator output voltage as the TS2951/A input is ramped up and down. The ERROR signal
becomes low at around 1.3V input,it goes high around 5V input (input voltage at which Vout=4.75V). The TS2951/A
dropout voltage depending on the load, the input voltage trip point around 5V will vary with load current. The output
voltage trip point is around 4.75V, it does not change with load. The error comparator has an open-collector output
which requires an external pull-up resistor. Depending on the system requirement, the resistor maybe returned to 5
or 3.3V output or other supply voltage depending to the system requirements. For determining the size of the
resistor, note that the output is sinking 400uA, this value adds to battery drain in a low better condition,
recommended values 100K to 1M . If the output is unused this resistor is not required.
Programming The output Voltage
The TS2951/A output voltage is programmable for any value from it reference voltage of 1.235V and it maximum
rating of 30V. For example for 5 volt needs to pin-strapped and using the internal voltage divider by tying pin 1 to 2
and pin 7 to pin 6. Refer to Figure 2, there are two external resistor required for this programming. Refer to the
below equation for the programming the output voltage:
Volt=Vref x (1+R1\R2)+I
FB
* R1
The Vref is 1.235V and I
FB
is the feedback bias current, nominally -20nA. The minimum recommended load current
of 1uA forces an upper limit of 1.2M on value of R2, If no load presented the I
FB
produces error of typically 2% in
Vout which maybe eliminated at room temperature by trimming R1. To improve the accuracy chooses the value of
R2=100K and this reduces the error by 0.17% and increases the resistor program current by 12uA. The TS2951/A
typically draw 60uA at no load with pin 2 open-circuit, and this value does not look much.
4/10
Version: D11
TS2951/A
150mA Ultra Low Dropout Voltage Regulator
Application Hints
(continued)
Figure 1. Error Output Timing
Figure 2. Adjust Voltage
Block Diagram and Typical Applications Circuit
5/10
Version: D11
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