3PEAK TPF632

2-VRMS Audio Line Driver with Integrated Charge Pump

Features Description
The 3PEAK INCORPORATED TPF632 are 2-VRMS
 2-VRMS Output into 2.5kΩ Load with 3.3V Supply pop-free stereo line drivers with the integrated
 Integrated Charge Pump Generates Negative charge pump generating the negative supply rail
Supply Rail which allows the removal of the output DC-blocking
capacitors. The devices are capable of driving
 0-V DC Voltage at Output
2-VRMS into a 2.5-kΩ load with single 3.3V supply
 Low Noise: VN = 4.3μVRMS at 20Hz to 20kHz voltage. The device has differential inputs, and can
 Low THD+N: 0.001% use external resistors for flexible gain setting.
 Drives 600Ω Load The TPF632 has built-in enable/shutdown control
 Stable with 220pF Capacitive Load for pop-free on/off control. The device has an
external under-voltage detector that mutes the
 Pop-Free Under-Voltage Protection output when monitored voltage drop below set value.
 Pop-Free Enable Control Using the TPF632 in audio products can reduce
 –40°C to 85°C Operation Range component count considerably compared to
traditional methods of generating a 2-VRMS output.
 Robust 8kV (Output) HBM ESD Rating
 Robust 2kV CDM ESD Rating The device needs only a single 3.3V supply to
generate 5.6-VPP output while a traditional op-amp
 Green, TSSOP-14 Package requires a split-rail power supply to achieve same.
The device is ideal for single-supply electronics
Applications where size and cost are critical design parameters.
3PEAK and the 3PEAK logo are registered trademarks of
 Set-Top Box 3PEAK INCORPORATED. All other trademarks are the property
of their respective owners.
 Blu-ray and HD DVD Players
 PDP TV and LCD TV
 Home Theater in a Box
Audio Line Drivers

Part
Package Remarks
Number
Pin Configuration (Top View) TPF632 TSSOP-14 3.3V, Differential inputs
TPF603 TSSOP-14 5V/3.3V, Differential inputs
TPF605 MSOP-10-EP 5V/3.3V, Single-ended inputs
5V/3.3V, Single-ended inputs,
TPF632 TPF607 MSOP-10
no UVP control
14-Pin TSSOP

+INR 1 14 +INL

-INR 2 13 -INL

OUTR 3 12 OUTL
DAC LEFT
GND 4 UVP 11 UVP

EN 5 10 PGND
TPF632
RIGHT
PVSS 6 9 PVDD
Charge
Pump DAC
CN 7 8 CP

Figure 1. Typical Application Circuit of TPF632

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TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

Order Information

Marking
Model Name Order Number Package Transport Media, Quantity
Information
TPF632 TPF632-TR 14-Pin TSSOP Tape and Reel, 3000 TPF632

Absolute Maximum Ratings Note 1

Supply Voltage: V+ – V–....................................4.0V Output Short-Circuit Duration Note 3…......... Indefinite

Input Voltage............................. V– – 0.3 to V+ + 0.3 Operating Temperature Range.......–40°C to 125°C
Input Current: +IN, –IN, SHDN Note 2.............. ±10mA Maximum Junction Temperature................... 150°C
EN Pin Voltage……………………………V– to V+ Storage Temperature Range.......... –65°C to 150°C
Output Current: OUT.................................... ±20mA Lead Temperature (Soldering, 10 sec) ......... 260°C

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum
Rating condition for extended periods may affect device reliability and lifetime.

Note 2: The inputs are protected by ESD protection diodes to each power supply. If the input extends more than 500mV beyond the power supply, the input
current should be limited to less than 10mA.

Note 3: A heat sink may be required to keep the junction temperature below the absolute maximum. This depends on the power supply voltage and how many
amplifiers are shorted. Thermal resistance varies with the amount of PC board metal connected to the package. The specified values are for short traces
connected to the leads.

ESD, Electrostatic Discharge Protection

Pin Symbol Parameter Condition Minimum Level Unit

Output HBM Human Body Model ESD MIL-STD-883H Method 3015.8 8 kV
Others HBM Human Body Model ESD MIL-STD-883H Method 3015.8 4 kV
All CDM Charged Device Model ESD JEDEC-EIA/JESD22-C101E 2 kV

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 TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

3V Electrical Characteristics
Specifications are at TA = 27° C. VDD = 3.3V, RL = 2.5kΩ, CPUMP=CPVSS=1F, CIN =10F, RIN = 10kΩ, RFB = 20kΩ, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VDD Supply Voltage Range 3.0 3.3 3.63 V

VOS Output Offset Voltage Input grounded, unity gain. -4 4 mV
IQ Quiescent Current No load 5.2 mA
IQ(off) Supply Current in Shutdown 0.2 mA
VO Output Voltage VDD=3.3V, f=1kHz, THD=1% 2.05 VRMS
Total Harmonic Distortion Plus
THD+N VO=2VRMS, f=1kHz 0.001 %
Noise
XTALK Crosstalk VO=2VRMS, f=1kHz -110 dB
ISC Short Circuit Current VDD=3.3V 20 mA
RIN Input Resistor Range 1 10 47 k
SR Slew Rate 5 V/μs
CL Maximum Capacitive Load 220 pF
VN Noise Output Voltage BW=20Hz to 20kHz 4.3 μVRMS
SNR Signal to Noise Ratio VO=3VRMS, f=1kHz, BW=20kHz 117 dB
GBW Unity Gain Bandwidth No load 10 MHz
AVOL Open-Loop Voltage Gain No load 130 dB
External Under-voltage
VUVP 1.23 V
Detection
External Under-voltage
IHYS 4.7 μA
Detection Hysteresis Current
fCP Charge Pump Frequency 330 kHz

Typical Performance Characteristics

Total Harmonic Distortion + Noise vs. Output Voltage Total Harmonic Distortion + Noise vs. Output Voltage
10
10

1 VDD =3.3V VDD =3.3V

1
THD+N (%)

RL =100kΩ
THD+N (%)

RL =2.5kΩ
f=1kHz f=1kHz
0.1 0.1

0.01 0.01

0.001 0.001

0.0001 0.0001
0.1 1 10 0.1 1 10
Output Voltage (V rms) Output Voltage (V rms)

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2-VRMS Audio Line Driver with Integrated Charge Pump

Typical Performance Characteristic

Total Harmonic Distortion + Noise vs. Frequency Quiescent Current vs. Supply Voltage

0.1 4

VDD =3.3V

Quiescent Current (mA)

THD+N (%)

RL =2.5kΩ 3.5
0.01 Vo=2Vrms

3
0.001

2.5

0.0001
10 100 1k 10k 100k 2
Frequency (Hz) 1 2 3 4
Supply Voltage (V)

Pin Functions

PIN
I/O Description
Name Number

+INR 1 I Positive input of the right channel OPAMP

-INR 2 I Negative input of the right channel OPAMP
OUTR 3 O Output of the right channel OPAMP
GND 4 P Ground
EN 5 I Enable
PVSS 6 P Negative supply generated with integrated charge pump
CN 7 I/O Negative terminal of the flying capacitor of the charge
CP 8 I/O Positive terminal of the flying capacitor of the charge
PVDD 9 P Positive supply
PGND 10 P Ground for charge pump
UVP 11 I Under-voltage protection input
OUTL 12 O Output of the left channel OPAMP
-INL 13 I Negative input of the left channel OPAMP
+INR 14 I Positive input of the left channel OPAMP

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 TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

Applications Information

Typical Application Circuit

-VINR -VINL
CIN RIN RFB RFB RIN CIN
VOUTR VOUTL

GND UVP UVP

EN PGND

PVSS PVDD
1µF Charge Pump 1µF
CN CP

1µF

Figure 2 Typical Application Circuit of TPF632

Typical application circuits are shown as above. TPF632 operates from a single supply voltage PVDD. It integrated
charge pump generates a negative supply –PVDD at the PVSS pin. The Line driving amplifiers work with dual supplies:
PVDD and –PVDD. Therefore, the DC level of the audio output can be designed to be 0V. A DC-blocking capacitor
typically seen in a single-supplied driver is not necessary.
The supply range of the TPF632 is 3.0V to 3.63V. For a 2VRMS output, the recommended supply voltage is 3.3V.RIN of
2.5k and RFB of 5k set the inverting gain of 2. Because of the exceptional noise performance of TPF632, the
dominant noise source is actually from RIN. To get better noise performance, lower input resistance and feedback
resistance may be used.

Integrated Charge Pump

The integrated charge pump in TPF632 generates negative power supply from a single supply PVDD. A flying
capacitor for the charge pump shall be applied between CP and CN. At the same time a decoupling capacitor shall be
applied between PVSS and ground. Typical value for the flying capacitor is 1uF. Typical value of the decoupling
capacitor shall be same as or larger than that of the flying capacitor. Low-ESR capacitors are recommended for the
flying capacitor and the decoupling capacitor.

Audio Signal Amplification Gain Setting

The main application of the TPF632 is to amplify/buffer audio signals and drive audio lines with very low distortion.
Typical application circuits with inverting gain are shown in Figure 3.
Non-inverting amplification of audio signals is also possible with same low distortion.

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TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

RFB RFB
CIN RIN
-VIN -VIN
VOUT VOUT
CIN RIN
+VIN
CIN RIN

RFB

(a) (b)

Figure 3 Typical Application Circuit of TPF632

AC-Coupling Input Capacitors

Because of the integrated charge pump that generates negative rail, TP632 may be used to amplify audio signal so the
output DC voltage is 0V. This usually requires the DC voltage of the input signal to be 0V. If the input signal has a DC
level other than 0V, an AC-coupling capacitor is necessary to block the DC voltage.
The AC-coupling capacitor essentially forms a high-pass filter at the input. The cut-off frequency of the filter has to be
low enough not to distort the input audio signal. For an inverting amplifier shown in Figure 4 the cut-off frequency may
be calculated as following: 1
fc = (1)
2 RINCIN
If the required maximum cut-off frequency is known, the minimum AC-coupling capacitance can be determined:

1
CIN  (2)
2 RINfc

Adding Low-Pass Filtering to the Gain

If low-pass filtering is necessary in addition to the audio signal amplification, a second-order filter can be implemented
as shown in Figure 4. Choice of C3, R1, R2, and R3 is based on the gain setting requirement and AC-coupling cut-off
frequency as discussed above. C1, C2 and C4 may be calculated depending on the bandwidth. Example choices of R
and C are listed in Table 1. If first-order filtering satisfies performance requirements, simply remove the C2 and C4 to
lower the component counts.

R3 R3

R1 R2 C1 C3 R1 R2 C1
-VIN -VIN
VOUT C4 VOUT
C3 +VIN
C2
C3 R1 R2 C1

R3
(a) (b)

Figure 4 Second-order filter with gain: (a) Single-ended input; (b) Differential input

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 TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

Table 1 Example RC setting at different gains

Gain R1 R2 R3 C1 C2 C3 C4

G=2 2.5k 2.5k 10k 120pF 1nF 2.2uF 360pF

G=2.5 2.4k 2.4k 12k 91pF 750pF 2.2uF 390pF
G=3.75 2k 2k 15k 75pF 750pF 4.7uF 390pF

Pop-Free Power Up and Power Down

During power up or power down, the input device that provide audio source may experience significant DC level shift.
Charging of the input capacitor due to DC shift will cause pop noise. It is recommended that TPF632 is disabled (EN
low) during power up and power down and kept disabled until charging of the input capacitor is complete. The
sequence of EN control is illustrated below.

Power

EN

Figure 5 The Sequence of EN Control

Under-voltage Protection
When unexpected power off happens, the host may not have enough time to disable TPF632 before pop noise is
generated. The integrated under-voltage protection circuits can be used to mute and disable TPF632 when the
monitored supply voltage drops below certain voltage.
The recommended connection is shown below. Vsupply is the monitored supply voltage. The threshold voltage at the
UVP pin is 1.23V. R3 sets the hysteresis voltage and is usually much larger than R1 and R2. The turn on threshold and
hysteresis can be calculated:

VTH = 1.23V x (R1+R2)/R2 (3)

Hysteresis = 4.7uA x R3 x (R1+R2)/R2 (4)
when R3>>R1, R2 (5)

Vsupply

R1

UVP
R3
R2

Figure 6 Under-voltage Protection Circuits

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2-VRMS Audio Line Driver with Integrated Charge Pump

ESD
TPF632 has reverse-biased ESD protection diodes on all inputs and outputs. Input and out pins can not be biased
more than 300mV beyond either supply rail.

Driving Large Capacitive Load

TPF632 is designed to drive large capacitive loads up to 220pF directly. When driving larger capacitive loads with the
TPF632, a small series resistor at the output (RISO in Figure 7 ) improves the feedback loop’s phase margin and
stability by making the output load resistive at higher frequencies. Usually RISO of 50 is sufficient.

R2

R1
VIN RISO
TPF632 VOUT

CLOAD

Figure 7 Driving Circuits

Power Supply Layout and Bypass

The power supply pin of TPF632 should have a local bypass capacitor (i.e., 0.01μF to 0.1μF) within 2mm for good high
frequency performance. It can also use a bulk capacitor (i.e., 1μF or larger) within 100mm to provide large, slow
currents. This bulk capacitor can be shared with other analog parts.
Ground layout improves performance by decreasing the amount of stray capacitance and noise at the OPA’s inputs
and outputs. To decrease stray capacitance, minimize PC board lengths and resistor leads, and place external
components as close to the op amps’ pins as possible.

Proper Board Layout

To ensure optimum performance at the PCB level, care must be taken in the design of the board layout. To avoid
leakage currents, the surface of the board should be kept clean and free of moisture. Coating the surface creates a
barrier to moisture accumulation and helps reduce parasitic resistance on the board.
Keeping supply traces short and properly bypassing the power supplies minimizes power supply disturbances due to
output current variation, such as when driving an ac signal into a heavy load. Bypass capacitors should be connected
as closely as possible to the device supply pins. Stray capacitances are a concern at the outputs and the inputs of the
amplifier. It is recommended that signal traces be kept at least 5mm from supply lines to minimize coupling.
A variation in temperature across the PCB can cause a mismatch in the Seebeck voltages at solder joints and other
points where dissimilar metals are in contact, resulting in thermal voltage errors. To minimize these thermocouple
effects, orient resistors so heat sources warm both ends equally. Input signal paths should contain matching numbers
and types of components, where possible to match the number and type of thermocouple junctions. For example,
dummy components such as zero value resistors can be used to match real resistors in the opposite input path.
Matching components should be located in close proximity and should be oriented in the same manner. Ensure leads
are of equal length so that thermal conduction is in equilibrium. Keep heat sources on the PCB as far away from
amplifier input circuitry as is practical.
The use of a ground plane is highly recommended. A ground plane reduces EMI noise and also helps to maintain a
constant temperature across the circuit board.

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 TPF632
2-VRMS Audio Line Driver with Integrated Charge Pump

Package Outline Dimensions

TSSOP-14

Dimensions
Symbol In Millimeters
MIN TYP MAX
A - - 1.20
E E1 A1 0.05 - 0.15
A2 0.90 1.00 1.05
b 0.20 - 0.28
c 0.10 - 0.19
D 4.86 4.96 5.06

e c E 6.20 6.40 6.60

E1 4.30 4.40 4.50
D e 0.65 BSC
A2
A

L 0.45 0.60 0.75

L1 1.00 REF
L2 0.25 BSC
A1
R 0.09 - -
θ 0° - 8°

R1
R

θ
L
L1 L2

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