DInverts Input Supply Voltage
DUp to 60-mA Output Current
DOnly Three Small 1-µF Ceramic Capacitors
Needed
DInput Voltage Range From 1.6 V to 5.5 V
DPowerSave-Mode for Improved Efficiency
applications
DLCD Bias
DGaAs Bias for RF Power Amps
DSensor Supply in Portable Instruments
DBipolar Amplifier Supply
DMedical Instruments
DBattery-Operated Equipment
at Low Output Currents (TPS60400)
DDevice Quiescent Current Typical 100 µA
DBV PACKAGE
(TOP VIEW)
DIntegrated Active Schottky-Diode for
Start-Up Into Load
DSmall 5-Pin SOT23 Package
OUT
1
2
IN
C
5
FLY+
DEvaluation Module Available
TPS60400EVM–178
C
FLY–
description
The TPS6040x is a family of devices that generate an unregulated negative output voltage from an input voltage
ranging from 1.6 V to 5.5 V . The devices are typically supplied by a preregulated supply rail of 5 V or 3.3 V . Due
to its wide input voltage range, two or three NiCd, NiMH, or alkaline battery cells, as well as one Li-Ion cell can
also power them.
Only three external 1-µF capacitors are required to build a complete dc/dc charge pump inverter. Assembled
in a 5-pin SOT23 package, the complete converter can be built on a 50 mm
and component count reduction is achieved by replacing the Schottky diode that is typically needed for start-up
into load by integrated circuitry.
3
4
GND
2
board area. Additional board area
The TPS6040x can deliver a maximum output current of 60 mA with a typical conversion efficiency of greater
than 90% over a wide output current range. Three device options with 20-kHz, 50-kHz, and 250-kHz fixed
frequency operation are available. One device comes with a variable switching frequency to reduce operating
current in applications with a wide load range and enables the design with low-value capacitors.
typical application circuit
TPS60400
1.6 V to 5.5 V
Input
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
C
1 µF
OUTPUT VOLTAGE
C
35
C
FLY–
2
I
(fly)
TPS60400
GND
4
1 µF
C
FLY+
0
–1
C
O
1 µF
Output
–1.6 V to –5 V,
Max 60 mA
–2
–3
– Output Voltage – V
O
V
–4
TA = 25°C
–5
012345
1
OUTIN
vs
INPUT VOLTAGE
IO = 60 mA
IO = 30 mA
IO = 1 mA
VI – Input Voltage – V
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 2001, Texas Instruments Incorporated
1
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
AVAILABLE OPTIONS
MARKING DBV
PART NUMBER
TPS60400DBVPFKI1
TPS60401DBVPFLI10Fixed frequency 20 kHz
TPS60402DBVPFMI3.3Fixed frequency 50 kHz
TPS60403DBVPFNI1Fixed frequency 250 kHz
†
The DBV package is available taped and reeled. Add R suffix to device type (e.g. TPS60400DBVR) to order quantities of
3000 devices per reel. Add T suffix to device type (e.g. TPS60400DBVT) to order quantities of 250 devices per reel.
†
PACKAGE
TPS60400 functional block diagram
V
I
TYPICAL FL YING CAPACITOR
[µF]
FEATURE
Variable switching frequency
50 kHz–250 kHz
MEAS
MEAS
V
I
VI / V
MEAS
VI – VCFLY+ < 0.5 V
V
I
VI < 1 V
VO > V
be
V
O
OSC
V
O
V
O
VCO_CONT
O
VO < –VI – V
CHG
OSC
50 kHz
VO > –1 V
be
R
Start
FF
S
Phase
Generator
DC_ Startup
Q
Q
Q
DC_ Startup
V
Q1
Q2
I
+
C
(fly)
Q4
B
Q3
Q5
V
O
GND
Terminal Functions
TERMINAL
NAMENO.
C
FLY+
C
FLY–
GND4Ground
IN2ISupply input. Connect to an input supply in the 1.6-V to 5.5-V range. Bypass IN to GND with a capacitor that has the
OUT1OPower output with VO = –V
I/O
5Positive terminal of the flying capacitor C
3Negative terminal of the flying capacitor C
same value as the flying capacitor.
Bypass OUT to GND with the output filter capacitor CO.
I
DESCRIPTION
(fly)
(fly)
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
detailed description
operating principle
The TPS60400, TPS60401 charge pumps invert the voltage applied to their input. For the highest performance,
use low equivalent series resistance (ESR) capacitors (e.g., ceramic). During the first half-cycle, switches S2
and S4 open, switches S1 and S3 close, and capacitor (C
half-cycle, S1 and S3 open, S2 and S4 close. This connects the positive terminal of C
negative to V
positive than –V
By connecting C
O.
, since switches S1–S4 have resistance and the load drains charge from CO.
I
in parallel, CO is charged negative. The actual voltage at the output is more
(fly)
V
I
S1
C
(fly)
1 µF
S2
S3
) charges to the voltage at VI. During the second
(fly)
S4
C
O
1 µF
VO (–VI)
to GND and the
(fly)
GND
GND
Figure 1. Operating Principle
charge-pump output resistance
The TPS6040x devices are not voltage regulators. The charge pumps output source resistance is
approximately 15 Ω at room temperature (with V
= 5 V), and VO approaches –5 V when lightly loaded. VO will
I
droop toward GND as load current increases.
= –(VI – RO × IO)
V
O
R
[
O
= output resistance of the converter
R
O
1
ƒosc C
(fly)
) 4ǒ2R
SWITCH
) ESR
CFLY
Ǔ
) ESR
CO
efficiency considerations
The power efficiency of a switched-capacitor voltage converter is affected by three factors: the internal losses
in the converter IC, the resistive losses of the capacitors, and the conversion losses during charge transfer
between the capacitors. The internal losses are associated with the IC’s internal functions, such as driving the
switches, oscillator, etc. These losses are af fected by operating conditions such as input voltage, temperature,
and frequency . The next two losses are associated with the voltage converter circuit’s output resistance. Switch
losses occur because of the on-resistance of the MOSFET switches in the IC. Charge-pump capacitor losses
occur because of their ESR. The relationship between these losses and the output resistance is as follows:
P
CAPACITOR LOSSES
+ P
CONVERSION LOSSES
= I
2
× R
O
O
(1)
R
SWITCH
f
= resistance of a single MOSFET-switch inside the converter
= oscillator frequency
OSC
The first term is the effective resistance from an ideal switched-capacitor circuit. Conversion losses occur during
the charge transfer between C
1
ƪ
+
P
CONV.LOSS
2
C
and C
(fly)
ǒ
V
(fly)
I
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
when there is a voltage difference between them. The power loss is:
O
2
* V
O
1
2
Ǔ
)
ǒ
C
V
O
2
RIPPLE
2
* 2VOV
RIPPLE
Ǔ
ƫ
ƒ
osc
(2)
3
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
efficiency considerations (continued)
The efficiency of the TPS6040x devices is dominated by their quiescent supply current at low output current and
by their output impedance at higher current.
h ^
I
O
IO) I
Q
ǒ
1*
I
R
O
O
Ǔ
V
I
Where, IQ = quiescent current.
capacitor selection
T o maintain the lowest output resistance, use capacitors with low ESR (see Table 1). The charge-pump output
resistance is a function of C
’s and CO’s ESR. Therefore, minimizing the charge-pump capacitor’s ESR
(fly)
minimizes the total output resistance. The capacitor values are closely linked to the required output current and
the output noise and ripple requirements. It is possible to only use 1-µF capacitors of the same type.
input capacitor (CI)
Bypass the incoming supply to reduce its ac impedance and the impact of the TPS6040x switching noise. The
recommended bypassing depends on the circuit configuration and where the load is connected. When the
inverter is loaded from OUT to GND, current from the supply switches between 2 x I
a large bypass capacitor (e.g., equal to the value of C
is loaded from IN to OUT , the circuit draws 2 × I
constantly, except for short switching spikes. A 0.1-µF bypass
O
) if the supply has high ac impedance. When the inverter
(fly)
and zero. Therefore, use
O
capacitor is sufficient.
flying capacitor (C
(fly)
)
Increasing the flying capacitor’s size reduces the output resistance. Small values increases the output
resistance. Above a certain point, increasing C
’s capacitance has a negligible effect, because the output
(fly)
resistance becomes dominated by the internal switch resistance and capacitor ESR.
output capacitor (C
)
O
Increasing the output capacitor’s size reduces the output ripple voltage. Decreasing its ESR reduces both output
resistance and ripple. Smaller capacitance values can be used with light loads if higher output ripple can be
tolerated. Use the following equation to calculate the peak-to-peak ripple.
Table 3 contains a list of manufacturers of the recommended capacitors. Ceramic capacitors will provide the
lowest output voltage ripple because they typically have the lowest ESR-rating.
Table 3. Recommended Capacitor Manufacturers
MANUFACTURERCAPACITOR TYPEINTERNET
Taiyo YudenX7R/X5R ceramicwww.t-yuden.com
TDKX7R/X5R ceramicwww.component.tdk.com
VishayX7R/X5R ceramicwww.vishay.com
KemetX7R/X5R ceramicwww.kemet.com
0805
0805
0805
1206
1206
1206
0805
0805
0805
0.47 µF
1 µF
2.2 µF
2.2 µF
4.7 µF
10 µF
1 µF
2.2 µF
3.3 µF
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
Storage temperature range, T
Maximum junction temperature, T
†
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 under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
TPS60402
TPS60403150250300
TPS60400CI = C
TPS60401CI = C
TPS60402CI = C
TPS60403CI = C
At TC = –40°C to 85°C, RL = 5 kΩ1.85.25
At TC ≥ 0°C, R
(fly)
C
IO = 5 mA
At VI = 5 V
At T ≤ 60°C,VI = 5 V
(fly)
(fly)
(fly)
(fly)
(fly)
C
(fly)
(fly)
= CO = 1 µF1215
= CO = 10 µF1215
= CO = 3.3 µF1215
= CO = 1 µF1215
= 5 kΩ1.6
L
60mA
= 1 µF, CO = 2.2 µF35
= CO = 10 µF20
= CO = 3.3 µF20
= CO = 1 µF15
305070
I
65190
120270
425700
210
135
210
mV
V
V
P–P
µA
µA
kHz
Ω
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
TYPICAL CHARACTERISTICS
Table of Graphs
ηEfficiencyvs Output current at 3.3 V, 5 V
I
I
V
f
f
Input currentvs Output current
I
Supply currentvs Input voltage
S
Output resistancevs Input voltage at –40°C, 0°C, 25°C, 85°C
Output voltagevs Output current at 25°C, VIN=1.8 V, 2.5 V, 3.3 V, 5 V
O
Oscillator frequencyvs Temperature at VI = 1.8 V, 2.5 V, 3.3 V, 5 V
OSC
Oscillator frequencyvs Output current TPS60400 at 2 V, 3.3 V, 5.0 V20
OSC
Output ripple and noiseVI = 5 V, IO = 30 mA, CI = C
TPS60400, TPS60401, TPS60402, TPS60403
TPS60400, TPS60401, TPS60402, TPS60403
TPS60400, TPS60401, TPS60402, TPS60403
TPS60400, CI = C
TPS60401, CI = C
TPS60402 , CI = C
TPS60403, CI = C
TPS60400, CI = C
TPS60401, CI = C
TPS60402 , CI = C
TPS60403, CI = C
TPS60400, TPS60401, TPS60402, TPS60403
VI = 5 V, IO = 30 mA, CI = C
VI = 5 V, IO = 30 mA, CI = C
VI = 5 V, IO = 30 mA, CI = C
= CO = 1 µF
(fly)
= CO = 10 µF
(fly)
= CO = 3.3 µF
(fly)
= CO = 1 µF
(fly)
= CO = 1 µF
(fly)
= CO = 10 µF
(fly)
= CO = 3.3 µF
(fly)
= CO = 1 µF
(fly)
TPS60400, TPS60401, TPS60402, TPS60403
SLVS324 – JULY 2001
FIGURE
2, 3
4, 5
6, 7
8, 9, 10,
11
12, 13,
14, 15
16, 17,
18, 19
= CO = 1 µF (TPS60400)
(fly)
= CO = 10 µF (TPS60401)
(fly)
= CO = 3.3 µF (TPS60402)
(fly)
= CO = 1 µF (TPS60403)
(fly)
21, 22
TPS60400, TPS60401
EFFICIENCY
vs
OUTPUT CURRENT
100
TPS60400
95
90
85
80
Efficiency – %
75
70
65
60
0102030405060708090100
TPS60401
VI = 3.3 V
IO – Output Current – mA
VI = 5 V
TPS60401
VI = 5 V
TPS60400
VI = 3.3 V
TA = 25°C
Figure 2
TPS60402, TPS60403
EFFICIENCY
vs
OUTPUT CURRENT
100
95
90
85
80
Efficiency – %
75
70
65
60
010 2030405060708090100
IO – Output Current – mA
TPS60403
VI = 5 V
TPS60402
VI = 5 V
TPS60403
VI = 3.3 V
TPS60402
VI = 3.3 V
TA = 25°C
Figure 3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
7
TPS60400, TPS60401, TPS60402, TPS60403
TPS60400, TPS60401
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
TYPICAL CHARACTERISTICS
INPUT CURRENT
vs
OUTPUT CURRENT
100
TA = 25°C
TPS60400
VI = 5 V
10
100
TA = 25°C
10
TPS60402, TPS60403
INPUT CURRENT
vs
OUTPUT CURRENT
TPS60403
VI = 5 V
TPS60401
VI = 5 V
1
– Input Current – mA
I
I
TPS60400
VI = 2 V
0.1
0.1110100
IO – Output Current – mA
TPS60401
VI = 2 V
Figure 4
TPS60400, TPS60401
SUPPLY CURRENT
vs
INPUT VOLTAGE
0.6
IO = 0 mA
TA = 25°C
0.4
TPS60403
VI = 2 V
1
– Input Current – mA
I
I
0.1
0.1110100
TPS60402
VI = 5 V
TPS60402
VI = 2 V
IO – Output Current – mA
Figure 5
TPS60402, TPS60403
SUPPLY CURRENT
vs
INPUT VOLTAGE
0.6
IO = 0 mA
TA = 25°C
0.4
TPS60403
0.2
– Supply Current – mA
DD
I
0
012345
VI – Input Voltage – V
TPS60400
TPS60401
Figure 6
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
– Supply Current – mA
0.2
DD
I
TPS60402
0
012345
VI – Input Voltage – V
Figure 7
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
TYPICAL CHARACTERISTICS
TPS60400
OUTPUT RESISTANCE
vs
INPUT VOLTAGE
40
IO = 30 mA
35
Ω
30
25
20
15
– Output Resistance –
o
r
10
5
0
123456
TA = 85°C
VI – Input Voltage – V
CI = C
TA = 25°C
TA = –40°C
= CO = 1 µF
(fly)
Figure 8
TPS60401
OUTPUT RESISTANCE
vs
INPUT VOLTAGE
40
IO = 30 mA
CI = C
35
30
Ω
25
20
15
10
– Output Resistance –
o
r
5
0
123456
= CO = 10 µF
(fly)
TA = 25°C
TA = –40°C
VI – Input Voltage – V
TA = 85°C
Figure 9
TPS60402
OUTPUT RESISTANCE
vs
INPUT VOLTAGE
40
IO = 30 mA
35
Ω
30
25
20
15
– Output Resistance –
o
r
10
5
0
123456
TA = 25°C
TA = –40°C
CI = C
TA = 85°C
VI – Input Voltage – V
= CO = 3.3 µF
(fly)
40
35
Ω
30
25
20
15
– Output Resistance –
o
10
r
5
TA = –40°C
0
123456
Figure 10
TPS60403
OUTPUT RESISTANCE
vs
INPUT VOLTAGE
IO = 30 mA
CI = C
TA = 25°C
TA = 85°C
VI – Input Voltage – V
= CO = 1 µF
(fly)
Figure 11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
9
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
TYPICAL CHARACTERISTICS
TPS60400
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
0
TA = 25°C
–1
–2
–3
–4
– Output Voltage – V
O
V
–5
–6
0 102030405060
VI = 1.8 V
VI = 2.5 V
VI = 3.3 V
VI = 5 V
IO – Output Current – mA
Figure 12
TPS60401
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
0
TA = 25°C
–1
–2
–3
–4
– Output Voltage – V
O
V
–5
–6
0 102030405060
VI = 1.8 V
VI = 2.5 V
VI = 3.3 V
VI = 5 V
IO – Output Current – mA
Figure 13
TPS60402
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
0
TA = 25°C
–1
–2
–3
–4
– Output Voltage – V
O
V
–5
–6
0 102030405060
VI = 1.8 V
VI = 2.5 V
VI = 3.3 V
VI = 5 V
IO – Output Current – mA
Figure 14
TPS60403
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
0
TA = 25°C
–1
–2
–3
–4
– Output Voltage – V
O
V
–5
–6
0 102030405060
VI = 1.8 V
VI = 2.5 V
VI = 3.3 V
VI = 5 V
IO – Output Current – mA
Figure 15
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
TYPICAL CHARACTERISTICS
TPS60400
OSCILLATOR FREQUENCY
vs
FREE-AIR TEMPERATURE
250
IO = 10 mA
200
150
100
– Oscillator Frequency – kHz
osc
50
f
0
–40–30 –20–100 102030405060708090
TA – Free-Air Temperature – °C
VI = 1.8 V
VI = 2.5 V
VI = 3.3 V
VI = 5 V
Figure 16
TPS60401
OSCILLATOR FREQUENCY
vs
FREE-AIR TEMPERATURE
24
IO = 10 mA
23.8
23.6
23.4
23.2
23
22.8
22.6
– Oscillator Frequency – kHz
osc
22.4
f
22.2
22
–40–30 –20–100 102030405060708090
VI = 3.3 V
VI = 5 V
VI = 2.5 V
VI = 1.8 V
TA – Free-Air Temperature – °C
Figure 17
TPS60402
OSCILLATOR FREQUENCY
vs
FREE-AIR TEMPERATURE
57
IO = 10 mA
56
55
54
53
52
– Oscillator Frequency – kHz
51
osc
f
50
49
–40–30 –20–100 102030405060708090
TA – Free-Air Temperature – °C
VI = 5 V
VI = 3.3 V
VI = 2.5 V
VI = 1.8 V
Figure 18
TPS60403
OSCILLATOR FREQUENCY
vs
FREE-AIR TEMPERATURE
250
240
230
220
210
200
190
180
– Oscillator Frequency – kHz
osc
170
f
160
150
–40–30 –20–100 102030405060708090
VI = 5 V
VI = 3.3 V
VI = 2.5 V
VI = 1.8 V
IO = 10 mA
TA – Free-Air Temperature – °C
Figure 19
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
11
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
TYPICAL CHARACTERISTICS
TPS60400
OSCILLATOR FREQUENCY
vs
OUTPUT CURRENT
300
TA = 25°C
250
VI = 1.8 V
200
150
100
– Oscillator Frequency – kHz
osc
f
50
0
0102030405060708090100
IO – Output Current – mA
VI = 3.3 V
VI = 5 V
Figure 20
– Output Voltage – mV
O
V
VI = 5 V
IO = 30 mA
50 mV/DIV
50 mV/DIV
TPS60401, TPS60402
OUTPUT VOLTAGE
vs
TIME
TPS60401
TPS60402
20 µs/DIV
t – Time – µs
Figure 21
– Output Voltage – mV
O
V
VI = 5 V
IO = 30 mA
100 mV/DIV
50 mV/DIV
TPS60400, TPS60403
OUTPUT VOLTAGE
vs
TIME
TPS60400
TPS60403
4 µs/DIV
t – Time – µs
Figure 22
12
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
voltage inverter
The most common application for these devices is a charge-pump voltage inverter (see Figure 23). This
application requires only two external components; capacitors C
necessary. Refer to the capacitor selection section for suggested capacitor types.
and CO, plus a bypass capacitor, if
(fly)
Input 5 V
C
1 µF
C
35
C1–C1+
2
I
1 µF
(fly)
TPS60400
GND
4
1
OUTIN
C
O
1 µF
–5 V ,
Max 60 mA
Figure 23. Typical Operating Circuit
For the maximum output current and best performance, three ceramic capacitors of 1 µF (TPS60400,
TPS60403) are recommended. For lower currents or higher allowed output voltage ripple, other capacitors can
also be used. It is recommended that the output capacitors has a minimum value of 1 µF . With flying capacitors
lower than 1 µF, the maximum output power will decrease.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
13
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
RC-post filter
V
I
C
(fly)
1 µF
GND
C
I
1 µF
1
OUTC1+
TPS60400
2
IN
3
C1–GND
5
R
C
O
1 µF
P
C
P
VO (–VI)
GND
4
Figure 24. TPS60400 and TPS60401 With RC-Post Filter
An output filter can easily be formed with a resistor (R
1
and ratio V
Ť
V
with R
= 50 Ω, CP = 0.1 µF and f = 250 kHz:
P
O/VOUT
V
O
OUT
+
ƒ
c
2pRPC
is:
Ť
+
Ǹ
1 )
(1)
P
1
ǒ
2pƒRPC
(2)
2
Ǔ
P
V
Ť
V
OUT
) and a capacitor (CP). Cutoff frequency is given by:
P
O
Ť
+ 0.125
The formula refers only to the relation between output and input of the ac ripple voltages of the filter.
LC-post filter
V
I
GND
Figure 25 shows a configuration with a LC-post filter to further reduce output ripple and noise.
14
C
I
1 µF
C
(fly)
1
OUTC1+
2
IN
3
C1–GND
1 µF
TPS60400
5
4
V
Figure 25. LC-Post Filter
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
OUT
C
1 µF
L
P
O
C
P
VO (–VI)
GND
TPS60400, TPS60401, TPS60402, TPS60403
()
V
POUT
V
POUT
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
APPLICATION INFORMATION
Table 4. Measurement Results on the TPS60400 (Typical)
Figure 26. TPS60400 as a High-Efficiency Rail Splitter
A switched-capacitor voltage inverter can be configured as a high efficiency rail-splitter . This circuit provides a
bipolar power supply that is useful in battery powered systems to supply dual-rail ICs, like operational amplifiers.
Moreover, the SOT23-5 package and associated components require very little board space.
After power is applied, the flying capacitor (C
This equalizes the voltage on those capacitors and draws current from V
output at 1/2 V
.
I
) connects alternately across the output capacitors C3 and CO.
(fly)
to VO as required to maintain the
I
The maximum input voltage between VI and GND in the schematic (or between IN and OUT at the device itself)
must not exceed 6.5 V.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
15
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
combined doubler/inverter
In the circuit of Figure 27, capacitors CI, C
and C
are the flying capacitors; CO and C2 are the output capacitors. Because both the inverter and doubler
(fly)
, and CO form the inverter, while C1 and C2 form the doubler . C1
(fly)
use part of the charge-pump circuit, loading either output causes both outputs to decline toward GND. Make
sure the sum of the currents drawn from the two outputs does not exceed 60 mA. The maximum output current at
V
must not exceed 30 mA. If the negative output is loaded, this current must be further reduced.
(pos)
II ≈ –IO + 2 × I
V
I
C
(fly)
1
OUTC1+
TPS60400
2
IN
3
+
C
1 µF
C1–GND
I
O(POS)
1 µF
+
5
4
C
C
1 µF
+
D
1
O
2
V
+
+
(pos)
–V
I
C
2
GNDGND
Figure 27. TPS60400 as Doubler/Inverter
cascading devices
Two devices can be cascaded to produce an even larger negative voltage (see Figure 28). The unloaded output
voltage is normally –2 × V
, but this is reduced slightly by the output resistance of the first device multiplied by the
I
quiescent current of the second. When cascading more than two devices, the output resistance rises
dramatically.
GND
V
I
C
1
OUTC1+
2
IN
3
C
I
1 µF
C1–GND
+
1 µF
(fly)
TPS60400
C
5
4
C
O
+
1 µF
GND
1
OUTC1+
2
IN
3
C1–GND
1 µF
(fly)
TPS60400
5
4
+
C
O
1 µF
VO (–2 VI)
GND
Figure 28. Doubling Inverter
16
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
paralleling devices
Paralleling multiple TPS6040xs reduces the output resistance. Each device requires its own flying capacitor
(C
), but the output capacitor (CO) serves all devices (see Figure 29). Increase CO’s value by a factor of n,
(fly)
where n is the number of parallel devices. Equation 1 shows the equation for calculating output resistance.
V
I
GND
C
I
1 µF
1
2
3
C
(fly)
OUTC1+
IN
C1–GND
1 µF
TPS60400
C
(fly)
5
4
1
OUTC1+
2
IN
3
C1–GND
1 µF
TPS60400
5
VO (–VI)
4
C
O
2.2 µF
+
GND
Figure 29. Paralleling Devices
active-Schottky diode
For a short period of time, when the input voltage is applied, but the inverter is not yet working, the output
capacitor is charged positive by the load. T o prevent the output being pulled above GND, a Schottky diode must
be added in parallel to the output. The function of this diode is integrated into the TPS6040x devices, which gives
a defined startup performance and saves board space.
A current sink and a diode in series can approximate the behavior of a typical, modern operational amplifier.
Figure 30 shows the current into this typical load at a given voltage. The TPS6040x devices are optimized to
start into these loads.
V
GND
I
C
1 µF
I
C
(fly)
53
TPS60400
2
IN
GND
4
1 µF
C1–C1+
OUT
Typical
Load
VO (–VI)
1
I
O
C
O
1 µF
+V
–V
Load Current
60 mA
25 mA
0.4 V 1.25 V5 V
0.4 V
Voltage at the Load
Figure 30. T ypical LoadFigure 31. Maximum Start-Up Current
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
17
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
shutting down the TPS6040x
If shutdown is necessary , use the circuit in Figure 32. The output resistance of the TPS6040x will typically be
15 Ω plus two times the output resistance of the buffer.
Connecting multiple buffers in parallel can reduce the output resistance of the buffer driving the IN pin.
V
I
C
(fly)
1 µF
VO (–VI)
SDN
GND
C
I
1 µF
1
OUTC1+
TPS60400
2
IN
3
C1–GND
5
C
O
1 µF
4
GND
Figure 32. Shutdown Control
GaAs supply
A solution for a –2.7-V/3-mA GaAs bias supply is proposed in Figure 33. The input voltage of 3.3 V is first inverted
with a TPS60403 and stabilized using a TL V431 low-voltage shunt regulator. Resistor R
used for filtering the output voltage.
R
C
O
1 µF
TLV431
P
R2
C
P
R1
VI (3.3 V)
GND
C
I
0.1 µF
C
(fly)
1
OUTC1+
TPS60400
2
IN
3
C1–GND
0.1 µF
5
4
with capacitor CP is
P
VO (–2.7 V/3 mA)
GND
R1
ǒ
+*
V
O
1 )
R2
A 0.1-µF capacitor was selected for C
18
Ǔ
Figure 33. GaAs Supply
V
* R1 I
ref
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
I(ref)
. By this, the output resistance of the inverter is about 52 Ω.
(fly)
GaAs supply (continued)
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
R
can be calculated using the following equation:
PMAX
R
PMAX
+
ǒ
VCO* V
O
I
O
* R
Ǔ
O
With: VCO = –3.3 V; VO = –2.7 V; IO = –3 mA
R
A 100-Ω resistor was selected for R
= 200 Ω – 52 Ω = 148 Ω
PMAX
.
P
The reference voltage across R2 is 1.24 V typical. With 5-µA current for the voltage divider, R2 gets:
With C
1.24 V
R2 +
2.7 * 1.24 V
R1 +
= 1 µF the ratio VO/VI of the RC post filter is:
P
V
O
Ť
Ť
+
V
I
[ 250 kW
5 mA
5 mA
[ 300 kW
1
Ǹ
1 )(2p125000Hz 100W 1 mF
2
)
[ 0.01
step-down charge pump
By exchanging GND with OUT (connecting the GND pin with OUT and the OUT pin with GND), a step-down
charge pump can easily be formed. In the first cycle S1 and S3 are closed, and C
charged. Assuming the same capacitance, the voltage across C
and CO is split equally between the
(fly)
capacitors. In the second cycle, S2 and S4 close and both capacitors with V
V
I
S1
C
VO (V
I/2
S2
(fly)
+
1 µF
S3
)
S4
Figure 34. Step-Down Principle
The maximum input voltage between V
GND
C
O
1 µF
VO (V
and GND in the schematic (or between IN and OUT at the device itself)
I
I/2
)
V
I
C
I
1 µF
GND
Figure 35. Step-Down Charge Pump Connection
/2 across are connected in parallel.
I
C
(fly)
1
OUTC1+
TPS60400
2
IN
3
C1–GND
with CO in series are
(fly)
1 µF
5
4
C
1 µF
must not exceed 6.5 V. For input voltages in the range of 6.5 V to 11 V, an additional Zener-diode is
recommended (see Figure 36).
VO (V
O
GND
I/2
)
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
19
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
5V6
V
I
C
(fly)
1 µF
GND
1 µF
1
OUT
TPS60400
2
IN
3
C1–
C
I
C1+
GND
5
4
Figure 36.
power dissipation
As given in the data sheet, the thermal resistance of the unsoldered package is R
the EVM, a typical thermal resistance of R
θJA(EVM)
The terminal resistance can be calculated using the following equation:
R
qJA
TJ* T
+
A
P
D
Where:
T
is the junction temperature.
J
T
is the ambient temperature.
A
P
is the power that needs to be dissipated by the device.
D
R
qJA
TJ* T
+
A
P
D
= 180°C/W was measured.
C
O
1 µF
VO – V
GND
I
= 347°C/W. Soldered on
θJA
The maximum power dissipation can be calculated using the following equation:
= VI × II – VO × IO = V
P
D
I(max)
× (IO + I
(SUPPLY)
) – VO × I
O
The maximum power dissipation happens with maximum input voltage and maximum output current.
At maximum load the supply current is 0.7 mA maximum.
= 5 V × (60 mA + 0.7 mA) – 4.4 V × 60 mA = 40 mW
P
D
With this maximum rating and the thermal resistance of the device on the EVM, the maximum temperature rise
above ambient temperature can be calculated using the following equation:
= R
∆T
J
This means that the internal dissipation increases T
× PD = 180°C/W × 40 mW = 7.2°C
θJA
by <10°C.
J
The junction temperature of the device shall not exceed 125°C.
This means the IC can easily be used at ambient temperatures up to:
20
= T
T
A
– ∆TJ = 125°C/W – 10°C = 115°C
J(max)
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
APPLICATION INFORMATION
layout and board space
All capacitors should be soldered as close as possible to the IC. A PCB layout proposal for a single-layer board
is shown in Figure 37. Care has been taken to connect all capacitors as close as possible to the circuit to achieve
optimized output voltage ripple performance.
CFLY
IN
OUT
GND
Figure 37. Recommended PCB Layout for TPS6040x (top layer)
device family products
Other inverting dc-dc converters from Texas Instruments are listed in Table 5.
TPS60400, TPS60401, TPS60402, TPS60403
UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER
SLVS324 – JULY 2001
MECHANICAL DATA
DBV (R-PDSO-G5)PLASTIC SMALL-OUTLINE
0,95
1,45
0,95
3,00
2,80
45
31
0,05 MIN
0,50
0,30
1,70
1,50
M
0,20
3,00
2,60
Seating Plane
0,10
0,15 NOM
Gage Plane
0°–8°
0,25
0,55
0,35
NOTES: A. All linear dimensions are in millimeters.
B. This drawing is subject to change without notice.
C. Body dimensions do not include mold flash or protrusion.
D. Falls within JEDEC MO-178
4073253-4/F 10/00
22
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
IMPORTANT NOTICE
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its products to the specifications applicable at the time of sale in accordance with
TI’s standard warranty . T esting and other quality control techniques are utilized to the extent TI deems necessary
to support this warranty . Specific testing of all parameters of each device is not necessarily performed, except
those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
products or services might be or are used. TI’s publication of information regarding any third party’s products
or services does not constitute TI’s approval, license, warranty or endorsement thereof.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
alteration and is accompanied by all associated warranties, conditions, limitations and notices. Representation
or reproduction of this information with alteration voids all warranties provided for an associated TI product or
service, is an unfair and deceptive business practice, and TI is not responsible nor liable for any such use.
Resale of TI’s products or services with
that product or service voids all express and any implied warranties for the associated TI product or service,
is an unfair and deceptive business practice, and TI is not responsible nor liable for any such use.
Also see: Standard T erms and Conditions of Sale for Semiconductor Products.
Copyright 2001, Texas Instruments Incorporated
statements different from or beyond the parameters
www.ti.com/sc/docs/stdterms.htm
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
stated by TI for
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