Texas Instruments DRV632EVM User manual

User's Guide
SLOU301–January 2010
DRV632EVM Evaluation Module
This user’s guide describes the operation of the DRV632 evaluation module. This document also provides
measurement data and design information including a schematic, bill of materials, and printed-circuit
board (PCB) layout drawings.
Contents
1 Overview ..................................................................................................................... 2
2 Quick Setup .................................................................................................................. 4
3 On/Off Sequence ............................................................................................................ 5
4 Component Selection ....................................................................................................... 5
5 Layout Recommendations ................................................................................................. 7
6 Related Documentation from Texas Instruments ....................................................................... 7
7 Design Documentation ..................................................................................................... 8
List of Figures
1 DRV632EVM Top View .................................................................................................... 2
2 DRV632EVM Bottom View ................................................................................................ 2
3 DRV632EVM Functional Block Diagram................................................................................. 3
4 Power-Up/-Down Sequence............................................................................................... 5
5 Second-Order, Active Low-Pass Filter ................................................................................... 6
6 Differential Input, Second-Order Active Low-Pass Filter............................................................... 6
7 DRV632EVM Schematic................................................................................................... 8
8 DRV632EVM PCB Component Placement ............................................................................ 10
9 DRV632EVM PCB Top Layer............................................................................................ 10
10 DRV632EVM PCB Bottom Layer........................................................................................ 11
List of Tables
1 Key Parameters............................................................................................................. 3
2 Recommended Supply Voltage ........................................................................................... 4
3 DRV632EVM Filter Specifications ........................................................................................ 6
4 Related Documentation .................................................................................................... 7
5 Bill of Materials.............................................................................................................. 9
DirectPath is a trademark of Texas Instruments.
Blu-ray Disc is a trademark of Blu-ray Disc Association.
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Overview www.ti.com
1 Overview
Figure 1. DRV632EVM Top View
Figure 2. DRV632EVM Bottom View
The DRV632EVM customer evaluation module (EVM) demonstrates the capabilities and operation of the
DRV632 integrated circuit from Texas Instruments.
The DRV632 is a 2-VRMS, pop-free, stereo line driver designed to allow removal of the output dc-blocking
capacitors in audio applications to reduce component count and overall cost. The device is ideal for
single-supply electronics where size and cost are critical design parameters.
Designed using TI’s patented DirectPath™ technology, the DRV632 is able to drive 2 VRMS into a 10-kΩ
load with 3.3-V supply voltage. The device has differential inputs and uses external gain-setting resistors
that support a gain range of ±1 V/V to ±10 V/V, and line outputs that have ±8 kV IEC electrostatic
discharge (ESD) protection. The DRV632 also has built-in shutdown control for pop-free, on/off control.
Using the DRV632 in audio product applications can reduce component counts considerably, compared to
traditional methods of generating a 2-VRMS output. The DRV632 does not require a power supply greater
than 3.3 V to generate its 5.6-VPP output, nor does it require a split-rail power supply. The DRV632
integrates its own charge pump to generate a negative supply rail that provides a clean, pop-free,
ground-biased 2-VRMS output. The DRV632 is available in a 14-pin TSSOP package.
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+3.3 V
R_OUT
L_OUT
DRV632PW
R_IN
L_IN
ON/OFF
www.ti.com Overview
This EVM is configured with two RCA phono input connectors for analog input; the output signal is
available on two RCA phono connectors. The power supply is connected via a two-pin, 2,54-mm header.
This evaluation board is designed for testing applications such as set-top boxes, LCD/PDP TVs, Blu-ray
Disc™ DVD players, DVD mini-component systems, home theater-in-a-box (HTIB) systems, or
soundcards.
This document presents EVM specifications, audio performance measurements graphs, and design
documentation that includes complete circuit descriptions, schematic diagrams, a parts list, and PCB
layout design. Gerber (layout) files are available from the TI Web site at www.ti.com.
Throughout this document, the abbreviation EVM and the term evaluation module are synonymous with
the DRV632EVM.
1.1 DRV632EVM Features
The DRV632EVM has these features:
• Two-channel evaluation module (double-sided, plated-through PCB layout)
• 2-VRMS line output
• No output capacitor required
• Shutdown button
Figure 3 illustrates the functional diagram for the EVM. Table 1 summarizes the key parameters.
Figure 3. DRV632EVM Functional Block Diagram
Table 1. Key Parameters
Key Parameters Specification/Unit
Supply Voltage 3.3 V
Number of Channels Two
Load Impedance 600 Ω(min)
Output Voltage 2 VRMS
Dynamic Range > 90 dB
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Quick Setup www.ti.com
2 Quick Setup
This section describes the DRV632EVM board with regard to the power supply and system interfaces. It
provides information about handling and unpacking the DRV632EVM, absolute operating conditions, and a
description of the factory default switch and jumper configurations.
The following subsections provide a step-by-step guide to configuring the DRV632EVM for device
evaluation.
2.1 Electrostatic Discharge Notice
CAUTION
Many of the components on the DRV632EVM are susceptible to damage by
electrostatic discharge (ESD). Customers are advised to observe proper ESD
handling precautions when unpacking and handling the EVM, including the use
of a grounded wrist strap at an approved ESD workstation.
Failure to observe proper ESD handling procedures may result in damage to
EVM components.
2.2 Unpacking the EVM
On opening the DRV632EVM package, ensure that the following items are included:
• One DRV632EVM evaluation board, including:
– One DRV632PW device
If either item is missing, contact the Texas Instruments Product Information Center nearest you to inquire
about a replacement.
2.3 Power-Supply Setup
A single power supply is required to power up the EVM. The power supply is connected to the EVM board
using a two-pin, 2,54-mm header (J1). Table 2 lists the recommended supply voltage.
Table 2. Recommended Supply Voltage
Description Voltage Limitations Current Requirement Cable
Power supply 3.3 V 0.10 A —
CAUTION
Applying voltages above the limitations given in Table 2 may cause permanent
damage to your hardware.
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PVDD
Enable
> 50 sm> 50 sm
www.ti.com On/Off Sequence
3 On/Off Sequence
For minimum click and pop interference during device power on and power off, the DRV632 Mute pin (pin
5) must be held low, primarily because of precharging of the ac-coupled input capacitors. The preferred
power-up/-down sequence is shown in Figure 4.
Figure 4. Power-Up/-Down Sequence
4 Component Selection
4.1 Charge Pump
The charge pump flying capacitor, C17, serves to transfer charge during the generation of the negative
supply voltage. The PVSS capacitor must be at least equal to the charge pump capacitor in order to allow
a maximum charge transfer. Low equivalent series resistance (ESR) capacitors are an ideal selection, with
a typical value of 1 mF. Capacitor values less than 1 mF can be used, but the maximum output can be
reduced. It is therefore recommended to validate the design with thorough testing.
4.2 Power-Supply Decoupling Capacitors
The DRV632 is a DirectPath™ line driver amplifier that requires adequate power-supply decoupling to
ensure that noise and total harmonic distortion (THD) are low. A good low ESR ceramic capacitor, C15
(1 mF typical), placed as close as possible to the device VDD leads is the best option. Placing this
decoupling capacitor close to the DRV632 device is important for amplifier performance. For filtering
lower-frequency noise signals, a 10-mF or greater capacitor placed near the audio amplifier may also help,
but is not required in most applications because of the high PSRR of the DRV632.
The charge pump circuit does apply ripple current on the VDD line, and an LC or RC filter may be needed
if noise-sensitive audio devices share the VDD supply.
4.3 Using the DRV632 as a Second-Order, Low-Pass Filter in Single-Ended Input Mode
Several audio digital-to-audio converters (DAC) used in typical consumer applications require an external
low-pass filter to remove out-of-band noise. This function is also possible with the DRV632; the EVM is
configured as a 30-kHz, second-order active Butterworth filter to accomplish this filtering using an MFB
(multiple feedback) topology. Furthermore, the DRV632 requires an ac-coupling capacitor to remove dc
content from the source.
The active low-pass filter component values can be calculated with the help of the TI FilterPro active filter
design program available at http://focus.ti.com/docs/toolsw/folders/print/filterpro.html on the TI Web site.
Figure 5 illustrates the circuit design for this configuration.
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R2
R1R3
C2CX
C1
C3
DRV632
R2
R2
R1R3C1
C1
C3
R1R3
C3
-In
+In
C2
DRV632
Component Selection www.ti.com
Figure 5. Second-Order, Active Low-Pass Filter
Table 3. DRV632EVM Filter Specifications
Single
Ended Differential
Gain High Pass Low Pass C1 C2 C2 C3 R1 R2 R3
–1 V/V 16 Hz 40 kHz 100 pF 680 pF 270 pF 1 mF 10 kΩ10 kΩ24 kΩ
–1.5 V/V 19 Hz 40 kHz 68 pF 680 pF 270 pF 1 mF 8.2 kΩ12 kΩ30 kΩ
–2 V/V 11 Hz 30 kHz 47 pF 470 pF 180 pF 1 mF 15 kΩ30 kΩ43 kΩ
–3.33 V/V 12 Hz 30 kHz 33 pF 470 pF 180 pF 1 mF 13 kΩ43 kΩ43 kΩ
–10 V/V 15 Hz 30 kHz 22 pF 1 nF 330 pF 2.2 mF 4.7 kΩ47kΩ27 kΩ
The resistor values must be low value to achieve low noise, but must be of high enough value to obtain a
small size ac-coupling capacitor. With the proposed values of 15 kΩ, 30 kΩ, and 43 kΩ, a dynamic range
(DYR) of 102 dB can be achieved with a small 2.2-mF input ac-coupling capacitor.
The MFB filter structure demands an operational amplifier that is unity-gain stable at high frequencies; this
requirement can be relaxed by adding the CXcapacitor value to be equal to C1. The DRV632 is unity-gain
stable, but stray capacitance and inductance from the PCB layout can affect the phase margin. Therefore,
TI recommends adding CX.
4.4 Using the DRV632 as a Differential Input, Second-Order Low-Pass Filter
The single-ended input, second-order filter described in Section 4.3 can easily be extended to have a
differential input, as shown in Figure 6.
Figure 6. Differential Input, Second-Order Active Low-Pass Filter
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www.ti.com Layout Recommendations
C2can be split into separate capacitors to ground with the double value; this technique increases the
common-mode filtering. Another capacitor, CX, set equal to C1can continue to be used from the negative
input to ground to limit the high-frequency gain to 2.
As with the single-ended input, the differential input filter component values can be calculated with the
help of the TI FilterPro active filter design program available on the TI Web site.
5 Layout Recommendations
5.1 GND Connections
The GND pins of the DRV632 must be routed separately back to the decoupling capacitor in order to
facilitate proper device operation. If the GND pins are connected directly to each other, the device
functions without risk of failure, but noise and THD performance can be reduced.
On the DRV632EVM, a star ground routing pattern is used; the star point is located directly below the
DRV632 device itself.
6 Related Documentation from Texas Instruments
The following related documents are available through the Texas Instruments Web site at
http://www.ti.com.These documents have detailed descriptions of the integrated circuits used in the design
of the DRV632EVM.
Table 4. Related Documentation
Part Number Literature Number
DRV632 SLOS681 data sheet
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R6
0603
15.0K
GND
C18
0603 1.0ufd/16V
GND
R12
0603
10K
R13
0603 2.20K
R14
0603
22.0K
GND
GND
0.5in 0.5in 0.5in 0.5in
C7
0805 180pfd/50V
J1 2
1
GND
GND
S1
GND
100K
0603
R3 R2
0603
100K
GND
R5
0603
100K 100K
0603
R4
15.0K
0603
R7 R9
0603
15.0K
R16
0603
43.0K 43.0K
0603
R17
30.0K
0603
R15
1.0ufd/16V 0603
C17
GND
+3.3V
GND
GND
1
2
3
RCA(Black)
LOUT
RCA (Red)
1
2
3
ROUT
R22
0603
33.0
1000pfd/50V 0603
C19
GND
GND
33.0
0603
R23
C20
0603 1000pfd/50V
GND
GND
R18
0603
43.0K
15.0K
0603
R11
C8
0805 180pfd/50V
0.1ufd/10V 0603
C2
+3.3V
+3.3V
Green
0805
3.3V
392
0603
R1
PGND
Red
UVP
GND
C14
0603 0.1ufd/10V
DRV632PW
TSSOP14-PW
U1
14 13121110 9 8
7654321
10K
0603
R21
+3.3V
100pfd/50V
0603
C13
GND
Orange
MUTE
R20
0603
30.0K
R19
0603
43.0K C12
0603 47pfd/50V
JP3 2
1
GND
C9
0603 47pfd/50V
R8
0603 30.0K
GND GND
47pfd/50V 0603
C10
30.0K 0603
R10
GND GND
C11
0603 47pfd/50V
JP1 2
1
GND
1
2
JP2
3
2
1
RCA (Red)
RIN
RCA (Black)
1
2
3
LIN
C1 0805 10ufd/6.3V
C15
0603 1.0ufd/16V
VSA
C4
2.2ufd/50V
+
2.2ufd/50V
C5
VSA
+
VSA
C6
2.2ufd/50V
+
2.2ufd/50V
C3
VSA
+
RIGHTIN
LEFTIN
POWER SUPPLY IN
LINE
OUT
LINE IN
STANDOFFS
MUTE LINE DRIVER
DUAL FOOTPRINT PADS
C0603 CERAMIC/SMD-VSA ELECTROLYTIC
DO NOT POPULATE
DO NOT POPULATE
Design Documentation www.ti.com
7 Design Documentation
7.1 Schematics
Figure 7. DRV632EVM Schematic
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7.2 Bill of Materials
The bill of materials (BOM) for the DRV632EVM is listed in Table 5.
Table 5. Bill of Materials
Qty Part Reference Description Manufacturer Mfr Part No
2 C19, C20 CAP SMD0603 CERM 1000PF 50V 5% COG ROHS TDK C1608C0G1H102J
4 C9–C12 CAP SMD0603 CERM 47PFD 50V 5% COG ROHS MURATA GRM1885C1H470JA01D
1 C13 CAP SMD0603 CERM 100PFD 50V 5% COG ROHS MURATA GRM1885C1H101JA01D
2 C7, C8 CAP SMD0805 CERM 180PFD 50V 5% NPO ROHS YAGEO CC0805JRNP09BN181
1 C2 CAP SMD0603 CERM 0.1UFD 10V 5% X7R ROHS KEMET C0603C104K8RACTU
3 C15, C17, C18 CAP ALUM-ELECT SMD-VSA 10UFD 16V 20% ROHS TDK C1608X7R1C105K
4 C3,C4,C5,C6 CAP ALUM-ELECT SMD-VSA 2.2uF 50V 20% ROHS PANASONIC EEE-1HS2R2SR
1 C1 CAP SMD0805 CERM 10UFD 6.3V X7R 10% ROHS AVX 08056C106KAT2A
2 R22, R23 RESISTOR SMD0603 33 Ω1% 1/10W ROHS PANASONIC ERJ-3EKF33R0V
1 R21 RESISTOR SMD0603 10K 5% 1/10W ROHS PANASONIC ERJ-3GEYJ103V
4 R6, R7, R9, R11 RESISTOR SMD0603 15.0KΩ1% 1/10W ROHS STACKPOLE ELECTRONICS RMCF0603FT15K0
4 R16–R19 RESISTOR SDM0603 20.0KΩ1% THICK FILM 1/16W ROHS YAGEO RC0603FR-0743KL
4 R8, R10, R15, R20 RESISTOR SMD0603 THICK FILM 30.0K 1% 1/10W ROHS YAGEO RC0603FR-0730KL
4 R2–R5 RESISTOR SMD0603 100KΩ5% 1/10W ROHS STACKPOLE ELECTRONICS RMCF0603JT100K
4 J1 ,JP1–JP3 HEADER THRU MALE 2 PIN 100LS GOLD ROHS SULLINS PBC02SAAN
2 LIN, LOUT JACK, RCA 3-PIN PCB-RA BLACK ROHS SWITCHCRAFT PJRAN1X1U01X
2 RIN ,ROUT JACK, RCA 3-PIN PCB-RA RED ROHS SWITCHCRAFT PJRAN1X1U03X
1 UVP PC TESTPOINT, RED, ROHS KEYSTONE ELECTRONICS 5000
1 MUTE PC TESTPOINT, ORANGE, ROHS KEYSTONE ELECTRONICS 5003
1 S1 SWITCH, MOM, 160G SMT 4X3MM ROHS E-SWITCH TL1015AF160QG
3 JP1–JP3 SHUNT, BLACK AU FLASH 0.100LS SULLINS SPC02SYAN
4 N/A 4-40 SCREW, STEEL 0.250 IN BUILDING FASTENERS PMS 440 0025 PH
4 N/A STANDOF ,4-40 0.5IN 3/16IN DIA ALUM RND F-F KEYSTONE ELECTRONICS 2027
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7.3 PCB Layers
Gerber files are available for download at the DRV632EVM product folder page on the TI Web site.
Component placement and board layout are illustrated in Figure 8,Figure 9, and Figure 10, respectively.
NOTE: Board layouts are not to scale. These figures are intended to show how the board is laid
out; they are not intended to be used for manufacturing DRV632EVM PCBs.
Figure 8. DRV632EVM PCB Component Placement
Figure 9. DRV632EVM PCB Top Layer
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