ST TS4871 User Manual

TS4871

OUTPUT RAIL TO RAIL 1W AUDIO POWER AMPLIFIER WITH STANDBY MODE

■OPERATING FROM VCC = 2.5V to 5.5V

■1W RAIL TO RAIL OUTPUT POWER @ Vcc=5V, THD=1%, f=1kHz, with 8Ω Load

■ULTRA LOW CONSUMPTION IN STANDBY MODE (10nA)

■75dB PSRR @ 217Hz from 5V to 2.6V

■ULTRA LOW POP & CLICK

■ULTRA LOW DISTORTION (0.1%)

■UNITY GAIN STABLE

■AVAILABLE IN SO8, MiniSO8 & DFN8 3x3mm

DESCRIPTION

The TS4871 is an Audio Power Amplifier capable of delivering 1W of continuous RMS Ouput Power into 8Ω load @ 5V.

This Audio Amplifier is exhibiting 0.1% distortion level (THD) from a 5V supply for a Pout = 250mW RMS. An external standby mode control reduces the supply current to less than 10nA. An internal thermal shutdown protection is also provided.

The TS4871 has been designed for high quality audio applications such as mobile phones and to minimize the number of external components.

The unity-gain stable amplifier can be configured by external gain setting resistors.

APPLICATIONS

■Mobile Phones (Cellular / Cordless)

■Laptop / Notebook Computers

■PDAs

■Portable Audio Devices

ORDER CODE

	Part	Temperature	Package			Marking
	Number	Range: I	D	S	Q
	TS4871	-40, +85°C	∙			4871I
				∙	∙	4871

MiniSO & DFN only available in Tape & Reel with T suffix(IST & IQT) D = Small Outline Package (SO) - also available in Tape & Reel (DT)

June 2003

PIN CONNECTIONS (Top View)

			TS4871IST - MiniSO8
	Standby			1	8	VOUT2
		Bypass		2	7	GND
		VIN+		3	6	VCC
		VIN-		4	5	VOUT1
		TS4871ID-TS4871IDT - SO8
	Standby			1	8	VOUT2
		Bypass		2	7	GND
		VIN+		3	6	VCC
		VIN-		4	5	VOUT1
			TS4871IQT - DFN8
		STANDBY		1	8	VOUT 2
		BYPASS		2	7	GND
			VIN+	3	6	Vcc
			VIN-	4	5	VOUT 1
	TYPICAL APPLICATION SCHEMATIC
			Cfeed
				Rfeed	Vcc
					6		Cs
Audio					Vcc
Input	Rin
		4	Vin-
				-
						Vout1	5
	Cin
		3	Vin+	+
							RL
							8 Ohms
Vcc					-
						Vout2	8
					Av=-1
		2	Bypass
					+
	Rstb
		1	Standby	Bias
					GND
						TS4871
	Cb				7
							1/28

TS4871

ABSOLUTE MAXIMUM RATINGS

Symbol	Parameter	Value	Unit
VCC	Supply voltage 1)	6	V
Vi	Input Voltage 2)	GND to VCC	V
Toper	Operating Free Air Temperature Range	-40 to + 85	°C
Tstg	Storage Temperature	-65 to +150	°C
Tj	Maximum Junction Temperature	150	°C
Rthja	Thermal Resistance Junction to Ambient 3)	175	°C/W
	SO8
	MiniSO8	215
	QNF8	70
Pd	Power Dissipation	Internally Limited4)
ESD	Human Body Model	2	kV
ESD	Machine Model	200	V
Latch-up	Latch-up Immunity	Class A
	Lead Temperature (soldering, 10sec)	260	°C

1.All voltages values are measured with respect to the ground pin.

2.The magnitude of input signal must never exceed VCC + 0.3V / GND - 0.3V

3.Device is protected in case of over temperature by a thermal shutdown active @ 150°C.

4.Exceeding the power derating curves during a long period, involves abnormal operating condition.

OPERATING CONDITIONS

	Symbol	Parameter	Value	Unit
	VCC	Supply Voltage	2.5 to 5.5	V
	VICM	Common Mode Input Voltage Range	GND to VCC - 1.2V	V
	VSTB	Standby Voltage Input :	GND ≤ VSTB ≤ 0.5V
		Device ON		V
		Device OFF	VCC - 0.5V ≤ VSTB ≤ VCC
	RL	Load Resistor	4 - 32	Ω
	Rthja	Thermal Resistance Junction to Ambient 1)		°C/W
		SO8	150
		MiniSO8	190
		DFN8 2)	41

1.This thermal resistance can be reduced with a suitable PCB layout (see Power Derating Curves Fig. 20)

2.When mounted on a 4 layers PCB

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						TS4871
ELECTRICAL CHARACTERISTICS
VCC = +5V, GND = 0V, Tamb = 25°C (unless otherwise specified)
Symbol		Parameter	Min.	Typ.	Max.	Unit
ICC	Supply Current			6	8	mA
	No input signal, no load
ISTANDBY	Standby Current	1)		10	1000	nA
	No input signal, Vstdby = Vcc, RL = 8Ω
Voo	Output Offset Voltage			5	20	mV
	No input signal, RL = 8Ω
Po	Output Power			1		W
	THD = 1% Max, f = 1kHz, RL = 8Ω
THD + N	Total Harmonic Distortion + Noise			0.15		%
	Po = 250mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
PSRR	Power Supply Rejection Ratio2)			75		dB
	f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
ΦM	Phase Margin at Unity Gain			70		Degrees
	RL = 8Ω, CL = 500pF
GM	Gain Margin			20		dB
	RL = 8Ω, CL = 500pF
GBP	Gain Bandwidth Product			2		MHz
	RL = 8Ω

1.Standby mode is actived when Vstdby is tied to Vcc

2.Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz

VCC = +3.3V, GND = 0V, Tamb = 25°C (unless otherwise specified) 3)

Symbol		Parameter	Min.	Typ.	Max.	Unit
ICC	Supply Current			5.5	8	mA
	No input signal, no load
ISTANDBY	Standby Current	1)		10	1000	nA
	No input signal, Vstdby = Vcc, RL = 8Ω
Voo	Output Offset Voltage			5	20	mV
	No input signal, RL = 8Ω
Po	Output Power			450		mW
	THD = 1% Max, f = 1kHz, RL = 8Ω
THD + N	Total Harmonic Distortion + Noise			0.15		%
	Po = 250mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
PSRR	Power Supply Rejection Ratio2)			75		dB
	f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
ΦM	Phase Margin at Unity Gain			70		Degrees
	RL = 8Ω, CL = 500pF
GM	Gain Margin			20		dB
	RL = 8Ω, CL = 500pF
GBP	Gain Bandwidth Product			2		MHz
	RL = 8Ω

1.Standby mode is actived when Vstdby is tied to Vcc

2.Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz

3.All electrical values are made by correlation between 2.6V and 5V measurements

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TS4871

ELECTRICAL CHARACTERISTICS

VCC = 2.6V, GND = 0V, Tamb = 25°C (unless otherwise specified)

Symbol		Parameter	Min.	Typ.	Max.	Unit
ICC	Supply Current			5.5	8	mA
	No input signal, no load
ISTANDBY	Standby Current	1)		10	1000	nA
	No input signal, Vstdby = Vcc, RL = 8Ω
Voo	Output Offset Voltage			5	20	mV
	No input signal, RL = 8Ω
Po	Output Power			260		mW
	THD = 1% Max, f = 1kHz, RL = 8Ω
THD + N	Total Harmonic Distortion + Noise			0.15		%
	Po = 200mW rms, Gv = 2, 20Hz < f < 20kHz, RL = 8Ω
PSRR	Power Supply Rejection Ratio2)			75		dB
	f = 217Hz, RL = 8Ω, RFeed = 22KΩ, Vripple = 200mV rms
ΦM	Phase Margin at Unity Gain			70		Degrees
	RL = 8Ω, CL = 500pF
GM	Gain Margin			20		dB
	RL = 8Ω, CL = 500pF
GBP	Gain Bandwidth Product			2		MHz
	RL = 8Ω

1.Standby mode is actived when Vstdby is tied to Vcc

2.Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the surimposed sinus signal to Vcc @ f = 217Hz

	Components	Functional Description
	Rin	Inverting input resistor which sets the closed loop gain in conjunction with Rfeed. This resistor also
		forms a high pass filter with Cin (fc = 1 / (2 x Pi x Rin x Cin))
	Cin	Input coupling capacitor which blocks the DC voltage at the amplifier input terminal
	Rfeed	Feed back resistor which sets the closed loop gain in conjunction with Rin
	Cs	Supply Bypass capacitor which provides power supply filtering
	Cb	Bypass pin capacitor which provides half supply filtering
	Cfeed	Low pass filter capacitor allowing to cut the high frequency
		(low pass filter cut-off frequency 1 / (2 x Pi x Rfeed x Cfeed))
	Rstb	Pull-up resistor which fixes the right supply level on the standby pin
	Gv	Closed loop gain in BTL configuration = 2 x (Rfeed / Rin)

REMARKS

1.All measurements, except PSRR measurements, are made with a supply bypass capacitor Cs = 100µF.

2.External resistors are not needed for having better stability when supply @ Vcc down to 3V. By the way, the quiescent current remains the same.

3.The standby response time is about 1µs.

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TS4871

Fig. 1 : Open Loop Frequency Response

Fig. 2 : Open Loop Frequency Response

Gain (dB)

						0									0
60			Gain	Vcc = 5V		-20			60		Gain		Vcc = 5V		-20
						-40
				RL = 8Ω									ZL = 8Ω + 560pF		-40
40				Tamb = 25°C		-60			40				Tamb = 25°C		-60
0	Phase					-80	Phase(Deg)	Gain(dB)	0	Phase					-80	Phase(Deg)
						-140									-140
20						-100			20						-100
						-120									-120
						-160									-160
-20						-180			-20						-180
						-200									-200
-40						-220			-40						-220
0.3	1	10	100	1000	10000
									0.3	1	10	100	1000	10000
			Frequency (kHz)									Frequency (kHz)

Fig. 3 : Open Loop Frequency Response

Fig. 4 : Open Loop Frequency Response

80						0
		Gain		Vcc = 3.3V		-20
60						-40
				RL = 8Ω
				Tamb = 25°C		-60
40						-80	Phase (Deg)
	Phase					-100
20						-120
Gain(dB)						-140
						-160
0
						-180
-20						-200
						-220
-40						-240
0.3	1	10	100	1000	10000

Frequency (kHz)

80						0
		Gain		Vcc = 3.3V		-20
60				ZL = 8Ω + 560pF		-40
				Tamb = 25°C		-60
40						-80
	Phase					-100
20						-120
Gain(dB)						-140	Phase(Deg)
						-160
0
						-180
-20						-200
						-220
-40						-240
0.3	1	10	100	1000	10000

Frequency (kHz)

Fig. 5 : Open Loop Frequency Response

80						0
		Gain		Vcc = 2.6V		-20
60						-40
				RL = 8Ω
				Tamb = 25°C		-60
40						-80
	Phase					-100
20						-120
Gain(dB)						-140	Phase(Deg)
						-160
0
						-180
-20						-200
						-220
-40						-240
0.3	1	10	100	1000	10000

Frequency (kHz)

Fig. 6 : Open Loop Frequency Response

80						0
		Gain		Vcc = 2.6V		-20
60						-40
				ZL = 8Ω + 560pF
				Tamb = 25°C		-60
40						-80	Phase (Deg)
	Phase					-100
20						-120
Gain(dB)						-140
						-160
0
						-180
-20						-200
						-220
-40						-240
0.3	1	10	100	1000	10000

Frequency (kHz)

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TS4871

Fig. 7 : Open Loop Frequency Response

Fig. 8 : Open Loop Frequency Response

Gain (dB)

100		-80			100
80	Phase	-100			80
60		-120			60
	Gain	-140	(Deg)Phase	(dB)Gain	Gain
40					40
20		-160			20
		-180

0	Vcc = 5V					0	Vcc = 3.3V
						-200
-20	CL = 560pF						CL = 560pF
						-20
	Tamb = 25°C						Tamb = 25°C
						-220
-40						-40
0.3	1	10	100	1000	10000	0.3	1	10

Frequency (kHz)

-80

Phase -100

-120

-140

-160

-180

-200

-220

-240 100 1000 10000

Frequency (kHz)

Phase (Deg)

Fig. 9 : Open Loop Frequency Response

	100					-80
	80			Phase		-100
	60					-120
(dB)		Gain				-140	(Deg)
	40
						-160
Gain							Phase
	20					-180
	0					-200
		Vcc = 2.6V
	-20	CL = 560pF				-220
		Tamb = 25°C
	-40					-240
	0.3	1	10	100	1000	10000

Frequency (kHz)

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TS4871

Fig. 10 : Power Supply Rejection Ratio (PSRR) vs Power supply

Fig. 11 : Power Supply Rejection Ratio (PSRR) vs Feedback Capacitor

	-30
		Vripple = 200mVrms
	-40	Rfeed = 22Ω
		Input = floating
		RL = 8Ω
(dB)	-50	Tamb = 25°C
PSRR	-60	Vcc = 5V, 3.3V & 2.6V
		Cb = 1μF & 0.1μF
	-70
	-80
	10	100	1000	10000	100000

Frequency (Hz)

PSRR (dB)

	-10
	-20	Vcc = 5, 3.3 & 2.6V	Cfeed=0
		Cb = 1μF & 0.1μF
	-30	Rfeed = 22kΩ	Cfeed=150pF
		Vripple = 200mVrms

	Input = floating	Cfeed=330pF
-40	RL = 8Ω
	Tamb = 25°C
-50
-60
-70			Cfeed=680pF
-80
10	100	1000	10000	100000

Frequency (Hz)

Fig. 12 : Power Supply Rejection Ratio (PSRR) vs Bypass Capacitor

		-10
		Cb=1μF	Vcc = 5, 3.3 & 2.6V
		-20	Rfeed = 22k
		Cb=10μF Rin = 22k, Cin = 1μF
		-30	Rg = 100Ω, RL = 8Ω
	(dB)		Tamb = 25°C
		-40	Cb=47μF
	PSRR
		-50
		-60

-70	Cb=100μF
-80
10	100	1000	10000	100000

Frequency (Hz)

Fig. 14 : Power Supply Rejection Ratio (PSRR) vs Feedback Resistor

	-10
	-20	Vcc = 5, 3.3 & 2.6V	Rfeed=110kΩ
		Cb = 1μF & 0.1μF
	-30	Vripple = 200mVrms
		Input = floating	Rfeed=47kΩ
(dB)		RL = 8Ω
	-40	Tamb = 25°C
PSRR	-50
	-60
			Rfeed=22kΩ
	-70

Rfeed=10kΩ

-80
10	100	1000	10000	100000

Frequency (Hz)

Fig. 13 : Power Supply Rejection Ratio (PSRR) vs Input Capacitor

	-10
	Cin=1μF	Vcc = 5, 3.3 & 2.6V
	Cin=330nF
		Rfeed = 22kΩ, Rin = 22k
	-20
		Cb = 1μF
	Cin=220nF
		Rg = 100Ω, RL = 8Ω
(dB)	-30	Tamb = 25°C
PSRR	-40

Cin=100nF

-50	Cin=22nF

-60
10	100	1000	10000	100000

Frequency (Hz)

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TS4871

Fig. 15 : Pout @ THD + N = 1% vs Supply Voltage vs RL

		1.4
	(W)	1.2	Gv = 2 & 10	8Ω
				6Ω
			Cb = 1μF
	N		F = 1kHz
	+	1.0		4Ω
			BW < 125kHz
	THD
		0.8	Tamb = 25°C
	1%			16Ω
	@
		0.6
	power
		0.4
	Output
		0.2		32Ω

0.0
2.5	3.0	3.5	4.0	4.5	5.0

Vcc (V)

Fig. 17 : Power Dissipation vs Pout

	1.4
		Vcc=5V
(W)	1.2	F=1kHz
		THD+N<1%	RL=4Ω
Dissipation	1.0
Power	0.8
	0.6
	0.4		RL=8Ω

0.2 RL=16Ω

0.0
0.0	0.2	0.4	0.6	0.8	1.0	1.2	1.4

Output Power (W)

Fig. 19 : Power Dissipation vs Pout

0.40 Vcc=2.6V

0.35F=1kHz

(W)	0.30	THD+N<1%
Dissipation		RL=4Ω
	0.20
	0.25
Power	0.15
	0.10	RL=8Ω

0.05	RL=16Ω
0.00
0.0	0.1	0.2	0.3	0.4

Output Power (W)

Fig. 16 : Pout @ THD + N = 10% vs Supply Voltage vs RL

		2.0	Gv = 2 & 10
	(W)	1.8		8Ω
			Cb = 1μF
	+N			6Ω
		1.6	F = 1kHz
	THD		BW < 125kHz	4Ω
		1.4
			Tamb = 25°C
	10%	1.2
	@	1.0		16Ω
	power	0.8
	Output	0.6
		0.4
		0.2		32Ω

0.0
2.5	3.0	3.5	4.0	4.5	5.0

Vcc (V)

Fig. 18 : Power Dissipation vs Pout

	0.6	Vcc=3.3V
	0.5	F=1kHz
		THD+N<1%	RL=4Ω
(W)	0.4
Dissipation
	0.3
Power
	0.2		RL=8Ω
	0.1

RL=16Ω 0.0

0.0	0.2	0.4	0.6	0.8
		Output Power (W)

Fig. 20 : Power Derating Curves

	2.0
	1.8
	1.6	QFN8
(W)
	1.4
Dissipation	1.2
	1.0
	0.8	SO8
Power
	0.6
	0.4

0.2			MiniSO8
0.0
0		25	50		75	100	125	150

Ambiant Temperature (°C)

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TS4871

Fig. 21 : THD + N vs Output Power

	10
	Rl = 4Ω
	Vcc = 5V
	Gv = 2
	Cb = Cin = 1μF
(%)	BW < 125kHz
	Tamb = 25°C
+ N	1
THD			20kHz
			20Hz, 1kHz
0.1		0.01	0.1	1
	1E-3

Output Power (W)

Fig. 22 : THD + N vs Output Power

	10
	RL = 4Ω, Vcc = 5V
	Gv = 10
	Cb = Cin = 1μF
	BW < 125kHz, Tamb = 25°C
(%)		20kHz
+ N
	1
THD			20Hz
0.1				1kHz
	1E-3	0.01	0.1	1

Output Power (W)

Fig. 23 : THD + N vs Output Power	Fig. 24 : THD + N vs Output Power
10	10

RL = 4Ω, Vcc = 3.3V	RL = 4Ω, Vcc = 3.3V
Gv = 2	Gv = 10

	Cb = Cin = 1μF			Cb = Cin = 1μF
(%)N	BW < 125kHz	(%)N	1	BW < 125kHz
	Tamb = 25°C			20kHz
				Tamb = 25°C
+	1	+
THD		THD
		20kHz

				0.1	20Hz	1kHz
0.1		20Hz, 1kHz
1E-3	0.01	0.1	1	1E-3	0.01	0.1	1
	Output Power (W)				Output Power (W)

Fig. 25 : THD + N vs Output Power

	10
		RL = 4Ω, Vcc = 2.6V
		Gv = 2
		Cb = Cin = 1μF
(%)		BW < 125kHz
		Tamb = 25°C
+ N	1
THD
		20kHz
	20Hz, 1kHz
0.1
	1E-3	0.01	0.1
		Output Power (W)

Fig. 26 : THD + N vs Output Power

	10
		RL = 4Ω, Vcc = 2.6V
		Gv = 10
		Cb = Cin = 1μF
(%)		BW < 125kHz
		Tamb = 25°C
N	1	20kHz
THD +
			20Hz
0.1		1kHz
	1E-3	0.01	0.1
		Output Power (W)

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