ON Semiconductor CS5171, CS5172, CS5173, CS5174 Technical data

CS5171

CS5171, CS5172, CS5173, CS5174

1.5 A 280 kHz/560 kHz

Boost Regulators

The CS5171/2/3/4 products are 280 kHz/560 kHz switching regulators with a high efficiency, 1.5 A integrated switch. These parts operate over a wide input voltage range, from 2.7 V to 30 V. The flexibility of the design allows the chips to operate in most power supply configurations, including boost, flyback, forward, inverting, and SEPIC. The ICs utilize current mode architecture, which allows excellent load and line regulation, as well as a practical means for limiting current. Combining high frequency operation with a highly integrated regulator circuit results in an extremely compact power supply solution. The circuit design includes provisions for features such as frequency synchronization, shutdown, and feedback controls for either positive or negative voltage regulation. These parts are pin−to−pin compatible with LT1372/1373.

Part Number	Frequency	Feedback Voltage Polarity
CS5171	280 kHz	positive
CS5172	280 kHz	negative
CS5173	560 kHz	positive
CS5174	560 kHz	negative

Features

•Pb−Free Packages are Available

•Integrated Power Switch: 1.5 A Guaranteed

•Wide Input Range: 2.7 V to 30 V

•High Frequency Allows for Small Components

•Minimum External Components

•Easy External Synchronization

•Built in Overcurrent Protection

•Frequency Foldback Reduces Component Stress During an Overcurrent Condition

•Thermal Shutdown with Hysteresis

•Regulates Either Positive or Negative Output Voltages

•Shut Down Current: 50 A Maximum

•Pin−to−Pin Compatible with LT1372/1373

•Wide Temperature Range

♦Industrial Grade: −40 °C to 125°C

♦Commercial Grade: 0°C to 125°C

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SOIC−8

D SUFFIX

CASE 751

PIN CONNECTIONS AND

MARKING DIAGRAM

	1		CS5171/3	8
VC			517xx ALYW				VSW
FB							PGND
Test							AGND
SS							VCC
		1	CS5172/4	8
VC			517xx ALYW				VSW
Test							PGND
NFB							AGND
SS							VCC
x			= 1, 2, 3, or 4
x			= E, G
A			= Assembly Location
L			= Wafer Lot
Y			= Year
W			= Work Week

ORDERING INFORMATION

See detailed ordering and shipping information in the package dimensions section on page 17 of this data sheet.

Semiconductor Components Industries, LLC, 2004	1	Publication Order Number:
June, 2004 − Rev. 20		CS5171/D

CS5171, CS5172, CS5173, CS5174

	R2
	3.72 k
	1	VC
	2	FB
C1
0.01 F	3	Test
SS	4	SS

3.3 V

CS5171/3

			D1	VOUT
VSW	8
				5 V
PGND	7		MBRS120T3
AGND	6
	L1			+ C3
VCC	5
	22	H		22 F

R1	R3	+
5 k	1.28 k	C2
		22 F

Figure 1. Applications Diagram

MAXIMUM RATINGS

Rating	Value	Unit
Junction Temperature Range, TJ	−40 to +150	°C
Storage Temperature Range, TSTORAGE	−65 to +150	°C
Package Thermal Resistance: Junction−to−Case, R JC	45	°C/W
Junction−to−Ambient, R JA	165	°C/W
Lead Temperature Soldering: Reflow (Note 1)	230 Peak	°C
ESD, Human Body Model	1.2	kV

Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected.

1. 60 second maximum above 183°C.

MAXIMUM RATINGS

Pin Name	Pin Symbol	VMAX	VMIN	ISOURCE	ISINK
IC Power Input	VCC	30 V	−0.3 V	N/A	200 mA
Shutdown/Sync	SS	30 V	−0.3 V	1.0 mA	1.0 mA
Loop Compensation	VC	6.0 V	−0.3 V	10 mA	10 mA
Voltage Feedback Input	FB	10 V	−0.3 V	1.0 mA	1.0 mA
	(CS5171/3 only)
Negative Feedback Input	NFB	−10 V	10 V	1.0 mA	1.0 mA
(transient, 10 ms)	(CS5172/4 only)
Test Pin	Test	6.0 V	−0.3 V	1.0 mA	1.0 mA
Power Ground	PGND	0.3 V	−0.3 V	4 A	10 mA
Analog Ground	AGND	0 V	0 V	N/A	10 mA
Switch Input	VSW	40 V	−0.3 V	10 mA	3.0 A

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CS5171, CS5172, CS5173, CS5174

ELECTRICAL CHARACTERISTICS (2.7 V< VCC < 30 V; Industrial Grade: −40 °C < TJ < 125°C;

Commercial Grade: 0°C < TJ < 125°C; For all CS5171/2/3/4 specifications unless otherwise stated.)

Characteristic	Test Conditions	Min	Typ	Max	Unit
Positive and Negative Error Amplifiers
FB Reference Voltage (CS5171/3 only)	VC tied to FB; measure at FB	1.246	1.276	1.300	V
NFB Reference Voltage (CS5172/4 only)	VC = 1.25 V	−2.55	−2.45	−2.35	V
FB Input Current (CS5171/3 only)	FB = VREF	−1.0	0.1	1.0	A
NFB Input Current (CS5172/4 only)	NFB = NVREF	−16	−10	−5.0	A
FB Reference Voltage Line Regulation	VC = FB	−	0.01	0.03	%/V
(CS5171/3 only)
NFB Reference Voltage Line Regulation	VC = 1.25 V	−	0.01	0.05	%/V
(CS5172/4 only)
Positive Error Amp Transconductance	IVC = ± 25 A	300	550	800	Mho
Negative Error Amp Transconductance	IVC = ± 5 A	115	160	225	Mho
Positive Error Amp Gain	(Note 2)	200	500	−	V/V
Negative Error Amp Gain	(Note 2)	100	180	320	V/V
VC Source Current	FB = 1.0 V or NFB = −1.9 V, V C = 1.25 V	25	50	90	A
VC Sink Current	FB = 1.5 V or NFB = −3.1 V, V C = 1.25 V	200	625	1500	A
VC High Clamp Voltage	FB = 1.0 V or NFB = −1.9 V;	1.5	1.7	1.9	V
	VC sources 25 A
VC Low Clamp Voltage	FB = 1.5 V or NFB = −3.1 V, V C sinks 25 A	0.25	0.50	0.65	V
VC Threshold	Reduce VC from 1.5 V until switching stops	0.75	1.05	1.30	V
Oscillator
Base Operating Frequency	CS5171/2, FB = 1 V or NFB = −1.9 V	230	280	310	kHz
Reduced Operating Frequency	CS5171/2, FB = 0 V or NFB = 0 V	30	52	120	kHz
Maximum Duty Cycle	CS5171/2	90	94	−	%
Base Operating Frequency	CS5173/4, FB = 1 V or NFB = −1.9 V	460	560	620	kHz
Reduced Operating Frequency	CS5173/4, FB = 0 V or NFB = 0 V	60	104	160	kHz
Maximum Duty Cycle	CS5173/4	82	90	−	%
NFB Frequency Shift Threshold	Frequency drops to reduced operating frequency	−0.80	−0.65	−0.50	V
FB Frequency Shift Threshold	Frequency drops to reduced operating frequency	0.36	0.40	0.44	V
Sync/ Shutdown
Sync Range	CS5171/2	320	−	500	kHz
Sync Range	CS5173/4	640	−	1000	kHz
Sync Pulse Transition Threshold	Rise time = 20 ns	2.5	−	−	V
SS Bias Current	SS = 0 V	−15	−3.0	−	A
	SS = 3.0 V	−	3.0	8.0	A
Shutdown Threshold	−	0.50	0.85	1.20	V
Shutdown Delay	2.7 V ≤ VCC ≤ 12 V	12	80	350	s
	12 V < VCC ≤ 30 V	12	36	200	s

2. Guaranteed by design, not 100% tested in production.

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CS5171, CS5172, CS5173, CS5174

ELECTRICAL CHARACTERISTICS (continued) (2.7 V< VCC < 30 V; Industrial Grade: −40 °C < TJ < 125°C; Commercial Grade: 0°C < TJ < 125°C; For all CS5171/2/3/4 specifications unless otherwise stated.)

Characteristic	Test Conditions	Min	Typ	Max	Unit
Power Switch
Switch Saturation Voltage	ISWITCH = 1.5 A, (Note 3)	−	0.8	1.4	V
	ISWITCH = 1.0 A, 0°C ≤ TJ ≤ 85°C	−	0.55	−	V
	ISWITCH = 1.0 A, −40 °C ≤ TJ ≤ 0°C	−	0.75	−	V
	ISWITCH = 10 mA	−	0.09	0.45	V
Switch Current Limit	50% duty cycle, Note 3	1.6	1.9	2.4	A
	80% duty cycle, Note 3	1.5	1.7	2.2	A
Minimum Pulse Width	FB = 0 V or NFB = 0 V, ISW = 4.0 A, (Note 3)	200	250	300	ns
ICC/ IVSW	2.7 V ≤ VCC ≤ 12 V, 10 mA ≤ ISW ≤ 1.0 A	−	10	30	mA/A
	12 V < VCC ≤ 30 V, 10 mA ≤ ISW ≤ 1.0 A	−	−	100	mA/A
	2.7 V ≤ VCC ≤ 12 V, 10 mA ≤ ISW ≤ 1.5 A, (Note 3)	−	17	30	mA/A
	12 V < VCC ≤ 30 V, 10 mA ≤ ISW ≤ 1.5 A, (Note 3)	−	−	100	mA/A
Switch Leakage	VSW = 40 V, VCC = 0V	−	2.0	100	A
General
Operating Current	ISW = 0	−	5.5	8.0	mA
Shutdown Mode Current	VC < 0.8 V, SS = 0 V, 2.7 V ≤ VCC ≤ 12 V	−	12	60	A
	VC < 0.8 V, SS = 0 V, 12 V ≤ VCC ≤ 30 V	−	−	100
Minimum Operation Input Voltage	VSW switching, maximum ISW = 10 mA	−	2.45	2.70	V
Thermal Shutdown	(Note 3)	150	180	210	°C
Thermal Hysteresis	(Note 3)	−	25	−	°C

3. Guaranteed by design, not 100% tested in production.

PACKAGE PIN DESCRIPTION

Package	Pin
Pin #	Symbol	Function
1	VC	Loop compensation pin. The VC pin is the output of the error amplifier and is used for loop compensation,
		current limit and soft start. Loop compensation can be implemented by a simple RC network as shown in the
		application diagram on page 2 as R1 and C1.
2	FB	Positive regulator feedback pin. This pin senses a positive output voltage and is referenced to 1.276 V. When
(CS5171/3		the voltage at this pin falls below 0.4 V, chip switching frequency reduces to 20% of the nominal frequency.
only)
2	Test	These pins are connected to internal test logic and should either be left floating or tied to ground. Connection
(CS5172/4)		to a voltage between 2 V and 6 V shuts down the internal oscillator and leaves the power switch running.
3
(CS5171/3)
3	NFB	Negative feedback pin. This pin senses a negative output voltage and is referenced to −2.5 V. When the volt-
(CS5172/4)		age at this pin goes above −0.65 V, chip switching frequency reduces to 20% of the nominal frequency.
4	SS	Synchronization and shutdown pin. This pin may be used to synchronize the part to nearly twice the base
		frequency. A TTL low will shut the part down and put it into low current mode. If synchronization is not used,
		this pin should be either tied high or left floating for normal operation.
5	VCC	Input power supply pin. This pin supplies power to the part and should have a bypass capacitor connected to
		AGND.
6	AGND	Analog ground. This pin provides a clean ground for the controller circuitry and should not be in the path of
		large currents. The output voltage sensing resistors should be connected to this ground pin. This pin is con-
		nected to the IC substrate.
7	PGND	Power ground. This pin is the ground connection for the emitter of the power switching transistor. Connection
		to a good ground plane is essential.
8	VSW	High current switch pin. This pin connects internally to the collector of the power switch. The open voltage
		across the power switch can be as high as 40 V. To minimize radiation, use a trace as short as practical.

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		CS5171, CS5172, CS5173, CS5174
VCC		Thermal
		Shutdown
	Shutdown	2.0 V						VSW
		Regulator
	Delay	Oscillator	S	PWM		Q	Driver	Switch
				Latch
	Timer				R
SS		Sync
		Frequency
		Shift 5:1
							×5
	200 k				Slope
		Negative			Compensation
	2.0 V
		Error Amp						63 m
NFB	250 k	+
							Ramp	PGND
CS5172/4
		−					Summer
only
						PWM
		−0.65 V Detector		+		Comparator
					−
		0.4 V Detector
FB		−
CS5171/3		+
only		Positive
	1.276 V	Error Amp
AGND
		VC

Figure 2. Block Diagram

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CS5171, CS5172, CS5173, CS5174

TYPICAL PERFORMANCE CHARACTERISTICS

	7.2
	7.0		VCC = 30 V
	6.8
(mA)	6.6
	6.4		VCC = 12 V
Current	6.2
	6.0
	5.8		VCC = 2.7 V
	5.6	50	100
	0

Temperature (°C)

Figure 3. ICC (No Switching) vs. Temperature

	70
	60			VCC = 30 V
(mA/A)	50	ISW = 1.5 A
	40
	30			VCC = 12 V
	20
	10			VCC = 2.7 V
	0	0	50	100
			Temperature (°C)

Figure 4. ICC/ IVSW vs. Temperature

1200						1.9
1000				−40 °C
(mV)	800			85 °C		1.8
CE(SAT)	600				(V)	1.7
				25 °C	IN
					V
V	400					1.6
	200
	0	500	1000			1.5	50	100
						0
			ISW (mA)				°
							Temperature ( C)

Figure 5. VCE(SAT) vs. ISW

Figure 6. Minimum Input Voltage vs. Temperature

		285
		280
	(kHz)	275
		270
	OSC
		265
	f
		260
		255

0	50	100
	Temperature (°C)

Figure 7. Switching Frequency vs. Temperature (CS5171/2 only)

fOSC (kHz)

570

565

560

555

550

545

540

535

530

525

520

0

50

100

Temperature (°C)

Figure 8. Switching Frequency vs. Temperature (CS5173/4 only)

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CS5171, CS5172, CS5173, CS5174

TYPICAL PERFORMANCE CHARACTERISTICS

100

Typical)of	75
(%	50
OSC	25
f
	0

VCC = (12 V)

−40 °C

85°C

25°C

350	380	400	420	450
		VFB (mV)

Figure 9. Switching Frequency vs. VFB (CS5171/3 only)

	Typical)of	100
		75
	(%	50
	OSC	25
	f
		0

VCC = (12 V)

85°C

−40 °C

25°C

−550	−660	−725
	VNFB (mV)

Figure 10. Switching Frequency vs. VNFB (CS5172/4 only)

	1.280
	1.278		VCC = 12 V		−2.42
									VCC = 30 V
Voltage(V)	1.276			Voltage(V)	−2.43
			VCC = 30 V
	1.272				−2.44
	1.274				−2.45
		VCC = 2.7 V				V	CC	= 12 V
					−2.46
	1.270				−2.47
									VCC = 2.7 V
	1.268				−2.48
		50	100			0		50	100
	0
		°						Temperature (°C)
		Temperature ( C)

Figure 11. Reference Voltage vs. Temperature	Figure 12. Reference Voltage vs. Temperature
(CS5171/3 only)	(CS5172/4 only)

	0.20
	0.18
( A)	0.16
						VCC = 12 V
	0.14
FB
I	0.12
	0.10
						VCC = 2.7 V
	0.08
		0		50		100

Temperature (°C)

Figure 13. IFB vs. Temperature (CS5171/3 only)

	−7
	−8
( A)	−9
	−10
NFB−11
I
	−12

−13

−14

0	50	100
	Temperature (°C)

Figure 14. INFB vs. Temperature (CS5172/ 4 only)

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