ST TS4994FC User Manual

TS4994FC

1.2 W differential input/output audio power amplifier with selectable standby

Features

■Differential inputs

■Near-zero pop & click

■100dB PSRR @ 217Hz with grounded inputs

■Operating range from VCC = 2.5V to 5.5V

■1.2W rail-to-rail output power @ VCC = 5V, THD = 1%, F = 1kHz, with 8Ω load

■90dB CMRR @ 217Hz

■Ultra-low consumption in standby mode (10nA)

■Selectable standby mode (active low or active high)

■Ultra fast startup time: 15ms typ.

■Available in 9-bump flip-chip (300mm bump diameter)

■Lead-free package

Description

The TS4994 is an audio power amplifier capable of delivering 1W of continuous RMS output power into an 8Ω load @ 5V. Due to its differential inputs, it exhibits outstanding noise immunity.

An external standby mode control reduces the supply current to less than 10nA. An STBY MODE pin allows the standby to be active HIGH or LOW. An internal thermal shutdown protection is also provided, making the device capable of sustaining short-circuits.

TS4994EIJT - Flip-chip (9 bumps)

Gnd

VO-

7

6

5 VO+

Bypass 8 9 4 Stdby

VIN+ 1	2	3 VIN-
	VCC	Stdby Mode

The device is equipped with common mode feedback circuitry allowing outputs to be always biased at VCC/2 regardless of the input common mode voltage.

The TS4994 is designed for high quality audio applications such as mobile phones and requires few external components.

Applications

■Mobile phones (cellular / cordless)

■Laptop / notebook computers

■PDAs

■Portable audio devices

Order codes

	Part number	Temperature range	Package	Packaging	Marking
	TS4994EIKJT		FC9 with back		A94
		-40°C, +85°C	coating	Tape & reel
	TS4994EIJT		Lead free flip-chip9		A94

December 2006

Rev 2

1/35

www.st.com

Contents	TS4994FC

Contents

1	Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 3
2	Absolute maximum ratings and operating conditions . . . . . . . . . . . . .		4
3	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
4	Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		23
	4.1	Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	23
	4.2	Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . .	23
	4.3	Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . .	23
	4.4	Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	24
	4.5	Calculating the influence of mismatching on PSRR performance . . . . . .	25
	4.6	CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	27
	4.7	Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	28
	4.8	Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	30
	4.9	Wake-up time: tWU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	30
	4.10	Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	31
	4.11	Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	31
	4.12	Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	31
5	Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		32
6	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		34

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TS4994FC	Application component information

1 Application component information

	Components	Functional description
	Cs	Supply bypass capacitor that provides power supply filtering.
	Cb	Bypass capacitor that provides half supply filtering.
	Rfeed	Feedback resistor that sets the closed loop gain in conjunction with Rin
		AV = closed loop gain = Rfeed/Rin.
	Rin	Inverting input resistor that sets the closed loop gain in conjunction with Rfeed.
	Cin	Optional input capacitor making a high pass filter together with Rin.
		(FCL = 1/(2πRinCin).

Figure 1. Typical application

						VCC
							+	Cs
				Rfeed1				1u
				20k		2	GND
						VCC
Diff. input - Cin1		Rin1
	+		3	Vin-		-		Vo+ 5
	220nF 20k
	Cin2	Rin2						Vo-
GND	+		1	Vin+		+
								7
	220nF 20k
								8 Ohms
Diff. Input +			8	Bypass		Bias
	Optional		Cb
		+
			1u			Standby
				Mode	Stdby	GND		TS4994IJ
		GND
				9	4	6
						GND	Rfeed2
							20k
			GNDVCC GNDVCC

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Absolute maximum ratings and operating conditions	TS4994FC

2 Absolute maximum ratings and operating conditions

	Table 1.	Absolute maximum ratings
	Symbol	Parameter	Value	Unit
	VCC	Supply voltage (1)	6	V
	V	Input voltage (2)	GND to V	V
	i		CC
	Toper	Operating free air temperature range	-40 to + 85	°C
	Tstg	Storage temperature	-65 to +150	°C
	Tj	Maximum junction temperature	150	°C
	R	Thermal resistance junction to ambient (3)	250	°C/W
	thja
	Pdiss	Power dissipation	internally limited	W
	ESD	Human body model	2	kV
		Machine model	200	V
		Latch-up immunity	200	mA
		Lead temperature (soldering, 10sec)	260	°C

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

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

3.The device is protected by a thermal shutdown active at 150°C.

Table 2.

Operating conditions

Symbol

Parameter

Value

Unit

VCC

Supply voltage

2.5 to 5.5

V

Standby mode voltage input:

VSM

Standby active LOW

V

=GND

V

SM

Standby active HIGH

VSM=VCC

Standby voltage input:

VSTBY

Device ON (V = GND) or device OFF (V

SM

= V

)

1.5 ≤ V

STBY

≤ V

CC

V

SM

CC

GND ≤

Device OFF (V

= GND) or device ON (V

SM

= V

)

V

STBY

≤ 0.4

(1)

SM

CC

TSD

Thermal shutdown temperature

150

°C

RL

Load resistor

≥ 4

Ω

Rthja

Thermal resistance junction to ambient

100

°C/W

1.The minimum current consumption (ISTBY) is guaranteed when VSTBY = GND or VCC (i.e. supply rails) for the whole temperature range.

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TS4994FC	Electrical characteristics

3	Electrical characteristics
Table 3.	Electrical characteristics for VCC = +5V, GND = 0V, Tamb = 25°C (unless otherwise
	specified)
Symbol	Parameter	Min.	Typ.	Max.	Unit
ICC	Supply current		4	7	mA
	No input signal, no load
	Standby current
ISTBY	No input signal, VSTBY = VSM = GND, RL = 8Ω		10	1000	nA
	No input signal, VSTBY = VSM = VCC, RL = 8Ω
Voo	Differential output offset voltage		0.1	10	mV
	No input signal, RL = 8Ω
VICM	Input common mode voltage	0.6		VCC - 0.9	V
	CMRR ≤ -60dB
Pout	Output power	0.8	1.2		W
	THD = 1% Max, F= 1kHz, RL = 8Ω
THD + N	Total harmonic distortion + noise		0.5		%
	Pout = 850mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Power supply rejection ratio with inputs grounded(1)
PSRRIG	F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		100		dB
	Vripple = 200mVPP
	Common mode rejection ratio
CMRR	F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		90		dB
	Vic = 200mVPP
SNR	Signal-to-noise ratio (A-weighted filter, AV = 2.5)		100		dB
	RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
GBP	Gain bandwidth product		2		MHz
	RL = 8Ω
	Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Unweighted, AV = 1		6
	A-weighted, AV = 1		5.5
VN	Unweighted, AV = 2.5		12		μVRMS
	A-weighted, AV = 2.5		10.5
	Unweighted, AV = 7.5		33
	A-weighted, AV = 7.5		28
	Unweighted, Standby		1.5
	A-weighted, Standby		1
tWU	Wake-up time(2)		15		ms
	Cb =1μF

1.Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC.

2.Transition time from standby mode to fully operational amplifier.

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Electrical characteristics	TS4994FC

Table 4. Electrical characteristics for VCC = +3.3V (all electrical values are guaranteed with correlation measurements at 2.6V and 5V), GND = 0V, Tamb = 25°C (unless otherwise specified)

Symbol	Parameter	Min.	Typ.	Max.	Unit
ICC	Supply current no input signal, no load		3	7	mA
	Standby current
ISTBY	No input signal, VSTBY = VSM = GND, RL = 8Ω		10	1000	nA
	No input signal, VSTBY = VSM = VCC, RL = 8Ω
Voo	Differential output offset voltage		0.1	10	mV
	No input signal, RL = 8Ω
VICM	Input common mode voltage	0.6		VCC - 0.9	V
	CMRR ≤ -60dB
Pout	Output power	300	500		mW
	THD = 1% max, F= 1kHz, RL = 8Ω
THD + N	Total harmonic distortion + noise		0.5		%
	Pout = 300mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Power supply rejection ratio with inputs grounded(1)
PSRRIG	F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		100		dB
	Vripple = 200mVPP
	Common mode rejection ratio
CMRR	F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		90		dB
	Vic = 200mVPP
SNR	Signal-to-noise ratio (A-weighted filter, AV = 2.5)		100		dB
	RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
GBP	Gain bandwidth product		2		MHz
	RL = 8Ω
	Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Unweighted, AV = 1		6
	A-weighted, AV = 1		5.5
VN	Unweighted, AV = 2.5		12		μVRMS
	A-weighted, AV = 2.5		10.5
	Unweighted, AV = 7.5		33
	A-weighted, AV = 7.5		28
	Unweighted, Standby		1.5
	A-weighted, Standby		1
tWU	Wake-up time(2)		15		ms
	Cb =1μF

1.Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC.

2.Transition time from standby mode to fully operational amplifier.

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TS4994FC			Electrical characteristics
Table 5.	Electrical characteristics for VCC = +2.6V, GND = 0V, Tamb = 25°C (unless otherwise
	specified)
Symbol	Parameter	Min.	Typ.	Max.	Unit
ICC	Supply current		3	7	mA
	No input signal, no load
	Standby current
ISTBY	No input signal, VSTBY = VSM = GND, RL = 8Ω		10	1000	nA
	No input signal, VSTBY = VSM = VCC, RL = 8Ω
Voo	Differential output offset voltage		0.1	10	mV
	No input signal, RL = 8Ω
VICM	Input common mode voltage	0.6		VCC- 0.9	V
	CMRR ≤-60dB
Pout	Output power	200	300		mW
	THD = 1% max, F= 1kHz, RL = 8Ω
THD + N	Total harmonic distortion + noise		0.5		%
	Pout = 225mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Power supply rejection ratio with inputs grounded(1)
PSRRIG	F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		100		dB
	Vripple = 200mVPP
	Common mode rejection ratio
CMRR	F = 217Hz, RL = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF		90		dB
	Vic = 200mVPP
SNR	Signal-to-noise ratio (A-weighted filter, AV = 2.5)		100		dB
	RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz
GBP	Gain bandwidth product		2		MHz
	RL = 8Ω
	Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω
	Unweighted, AV = 1		6
	A-weighted, AV = 1		5.5
VN	Unweighted, AV = 2.5		12		μVRMS
	A-weighted, A = 2.5		10.5
	V
	Unweighted, AV = 7.5		33
	A-weighted, AV = 7.5		28
	Unweighted, Standby		1.5
	A-weighted, Standby		1
tWU	Wake-up time(2)		15		ms
	Cb =1μF

1.Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC.

2.Transition time from standby mode to fully operational amplifier.

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Electrical characteristics	TS4994FC
Figure 2. Current consumption vs. power	Figure 3. Current consumption vs. standby
supply voltage	voltage

	4.0	No load
	3.5	Tamb=25°C
(mA)	3.0
Consumption	2.5
	2.0
	1.5
Current
	1.0
	0.5
	0.0
	0	1	2	3	4	5

Power Supply Voltage (V)

	4.0
	3.5
(mA)	3.0			Standby mode=0V
Consumption	2.5		Standby mode=5V
	2.0
	1.5
Current
	1.0				Vcc = 5V
	0.5				No load
					Tamb=25°C
	0.0
	0	1	2	3	4	5

Standby Voltage (V)

Figure 4. Current consumption vs. standby Figure 5.	Current consumption vs. standby
voltage	voltage

	3.5
(mA)	3.0
	2.5			Standby mode=0V
Consumption
	2.0		Standby mode=3.3V
	1.5
Current	1.0
	0.5					Vcc = 3.3V
						No load
						Tamb=25°C
	0.0
	0.0	0.6	1.2	1.8	2.4	3.0

Standby Voltage (V)

Current Consumption (mA)

3.0
2.5	Standby mode=0V
2.0	Standby mode=2.6V

1.5

1.0

0.5

Vcc = 2.6V

No load

Tamb=25°C 0.0

0.0	0.6	1.2	1.8	2.4
		Standby Voltage (V)

Figure 6. Differential DC output voltage vs. Figure 7. Power dissipation vs. output power common mode input voltage

1000			1.4

Av = 1		Vcc=5V
Tamb = 25°C	1.2	F=1kHz

	100								Vcc=3.3V			(W)	THD+N<1%						RL=4Ω
			Vcc=2.5V										1.0
(mV)Voo												Dissipation
													0.6
	10
													0.8
								Vcc=5V
	1											Power
													0.4						RL=8Ω
	0.1
													0.2
																	RL=16Ω
	0.01												0.0
	0.0	0.5	1.0	1.5	2.0	2.5	3.0	3.5	4.0	4.5	5.0		0.0	0.2	0.4	0.6	0.8	1.0	1.2	1.4	1.6
			Common Mode Input Voltage (V)														Output Power (W)

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TS4994FC	Electrical characteristics

Figure 8. Power dissipation vs. output power Figure 9. Power dissipation vs. output power

Power Dissipation (W)

0.6	0.40
Vcc=3.3V		Vcc=2.6V
F=1kHz	0.35	F=1kHz

0.5	THD+N<1%	RL=4Ω			THD+N<1%
			(W)	0.30	RL=4Ω
0.4
			Dissipation	0.25
0.3				0.20
0.2		RL=8Ω	Power	0.15
				0.10	RL=8Ω
0.1				0.05
	RL=16Ω				RL=16Ω

0.0								0.00
0.0	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.0	0.1	0.2	0.3	0.4
			Output Power (W)							Output Power (W)

Figure 10. Output power vs. power supply	Figure 11. Output power vs. power supply
voltage	voltage

	2.4									2.0
	2.2	RL = 4Ω								1.8	RL = 8Ω
	2.0	F = 1kHz		THD+N=10%							F = 1kHz
		BW < 125kHz								1.6	BW < 125kHz
(W)	1.8	Tamb = 25°C							(W)	1.4	Tamb = 25°C			THD+N=10%
	1.6
power	1.4								power	1.2
	1.2									1.0
Output	1.0								Output	0.6
										0.8
	0.8
	0.6					THD+N=1%									THD+N=1%
										0.4
	0.4
	0.2									0.2
	0.0									0.0
	2.5		3.0	3.5	4.0	4.5	5.0	5.5		2.5		3.0	3.5	4.0	4.5	5.0	5.5
					Vcc (V)									Vcc (V)

Figure 12. Output power vs. power supply	Figure 13. Output power vs. power supply
voltage	voltage

Output power (W)

1.2		0.6

RL = 16Ω

RL = 32Ω

1.0		F = 1kHz																				0.5		F = 1kHz
		BW < 125kHz																						BW < 125kHz
0.8		Tamb = 25			°	C															(W)			Tamb = 25			°	C
										THD+N=10%												0.4									THD+N=10%
0.6																					power	0.3
0.4																					Output	0.2
0.2															THD+N=1%							0.1														THD+N=1%
0.0																						0.0
2.5			3.0					3.5				4.0			4.5		5.0		5.5			2.5			3.0					3.5			4.0			4.5		5.0		5.5
												Vcc (V)																					Vcc (V)

9/35

Electrical characteristics	TS4994FC
Figure 14. Power derating curves	Figure 15. Open loop gain vs. frequency

(W)	1.2
Dissipation	0.8			Heat sink surface ≈ 100mm2
	1.0			(See demoboard)
Power	0.6
Package	0.4
Chip-Flip	0.2	No Heat sink
	0.0
	0	25	50	75	100	125
			Ambiant Temperature ( C)

						0
	60
				Gain		-40
	40
						-80
Gain (dB)	20		Phase			-120Phase(°)
	0
	-20	Vcc = 5V				-160
		ZL = 8Ω + 500pF
		Tamb = 25°C
	-40					-200
	0.1	1	10	100	1000	10000

Frequency (kHz)

Figure 16. Open loop gain vs. frequency

Figure 17. Open loop gain vs. frequency

						0							0
	60							60
				Gain		-40					Gain		-40
	40							40
						-80							-80
Gain (dB)	20		Phase			-120Phase(°)	Gain (dB)	20		Phase			-120Phase(°)
	0							0
	-20	Vcc = 3.3V				-160		-20	Vcc = 2.6V				-160
		ZL = 8Ω + 500pF							ZL = 8Ω + 500pF
		Tamb = 25°C							Tamb = 25°C
	-40					-200		-40					-200
	0.1	1	10	100	1000	10000		0.1	1	10	100	1000	10000
			Frequency (kHz)							Frequency (kHz)

Figure 18. Closed loop gain vs. frequency

Figure 19. Closed loop gain vs. frequency

Gain (dB)

10												0
										Phase
0			Gain									-40
													(°)
-10												-80
													Phase
-20												-120
-30		Vcc = 5V										-160
		Av = 1
		ZL = 8		Ω	+ 500pF
-40		Tamb = 25				°	C					-200
0.1		1						10	100	1000		10000

Frequency (kHz)

Gain (dB)

10												0
										Phase
0			Gain									-40
													(°)
-10												-80
													Phase
-20												-120
-30		Vcc = 3.3V										-160
		Av = 1
		ZL = 8		Ω	+ 500pF
-40		Tamb = 25				°	C					-200
0.1		1						10	100	1000		10000

Frequency (kHz)

10/35

TS4994FC	Electrical characteristics
Figure 20. Closed loop gain vs. frequency	Figure 21. PSRR vs. frequency

	10				Phase	0		0
								-10	Vcc = 5V
		Gain
	0					-40		-20	Vripple = 200mVpp
									Inputs = Grounded
								-30
									Av = 1, Cin = 4.7μF
								-40
	-10					-80			RL ≥ 8Ω
										Cb=0.1μF
								-50	Tamb = 25°C
Gain(dB)						-120Phase(°)	PSRR(dB)
								-60		Cb=0.47μF
	-20							-70		Cb=1μF
								-80
	-30	Vcc = 2.6V				-160		-90
		Av = 1
								-100
		ZL = 8Ω + 500pF									Cb=0
								-110
	-40	Tamb = 25°C				-200
								-120
	0.1	1	10	100	1000	10000		20	100	1000	10000	20k
			Frequency (kHz)							Frequency (Hz)

Figure 22. PSRR vs. frequency

Figure 23. PSRR vs. frequency

	0						0
	-10	Vcc = 3.3V					-10	Vcc = 2.6V
	-20	Vripple = 200mVpp					-20	Vripple = 200mVpp
	-30	Inputs = Grounded					-30	Inputs = Grounded
		Av = 1, Cin = 4.7μF						Av = 1, Cin = 4.7μF
	-40						-40
(dB)		RL ≥ 8Ω				(dB)		RL ≥ 8Ω
			Cb=0.1μF						Cb=0.1μF
	-50	Tamb = 25°C					-50	Tamb = 25°C
PSRR	-60		Cb=0.47μF			PSRR	-60		Cb=0.47μF
	-70		Cb=1μF				-70		Cb=1μF
	-80						-80
	-90						-90
	-100			Cb=0			-100			Cb=0
	-110						-110
	-120						-120
	20	100	1000	10000	20k		20	100	1000	10000	20k
			Frequency (Hz)						Frequency (Hz)

Figure 24. PSRR vs. frequency

Figure 25. PSRR vs. frequency

	0
	-10	Vcc = 5V
	-20	Vripple = 200mVpp
	-30	Inputs = Grounded
		Av = 2.5, Cin = 4.7μF
	-40
(dB)		RL ≥ 8Ω	Cb=0.1μF
	-50	Tamb = 25°C
PSRR	-60		Cb=0.47μF
	-70		Cb=1μF
	-80
	-90
	-100			Cb=0
	-110
	-120
	20	100	1000	10000	20k
			Frequency (Hz)

	0
	-10	Vcc = 3.3V
	-20	Vripple = 200mVpp
	-30	Inputs = Grounded
		Av = 2.5, Cin = 4.7μF
	-40
(dB)		RL ≥ 8Ω	Cb=0.1μF
	-50	Tamb = 25°C
PSRR	-60		Cb=0.47μF
	-70		Cb=1μF
	-80
	-90
	-100			Cb=0
	-110
	-120
	20	100	1000	10000	20k
			Frequency (Hz)

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