TEXAS INSTRUMENTS UCC1800, UCC1801, UCC1802, UCC1803, UCC1804 Technical data

application

INFO

available

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

Low-Power BiCMOS Current-Mode PWM

FEATURES

•100 A Typical Starting Supply Current

•500 A Typical Operating Supply Current

•Operation to 1MHz

•Internal Soft Start

•Internal Fault Soft Start

•Internal Leading-Edge Blanking of the Current Sense Signal

•1 Amp Totem-Pole Output

•70ns Typical Response from Current-Sense to Gate Drive Output

•1.5% Tolerance Voltage Reference

•Same Pinout as UC3842 and UC3842A

DESCRIPTION

The UCC1800/1/2/3/4/5 family of high-speed, low-power integrated circuits contain all of the control and drive components required for off-line and DC-to-DC fixed frequency current-mode switching power supplies with minimal parts count.

These devices have the same pin configuration as the UC1842/3/4/5 family, and also offer the added features of internal full-cycle soft start and internal leading-edge blanking of the current-sense input.

The UCC1800/1/2/3/4/5 family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of critical voltage levels. Lower reference parts such as the UCC1803 and UCC1805 fit best into battery operated systems, while the higher reference and the higher UVLO hysteresis of the UCC1802 and UCC1804 make these ideal choices for use in off-line power supplies.

The UCC180x series is specified for operation from –55oC to +125oC, the UCC280x series is specified for operation from –40oC to +85oC, and the UCC380x series is specified for operation from 0oC to +70oC.

Part Number	Maximum Duty Cycle	Reference Voltage	Turn-On Threshold	Turn-Off Threshold
UCCx800	100%	5V	7.2V	6.9V
UCCx801	50%	5V	9.4V	7.4V
UCCx802	100%	5V	12.5V	8.3V
UCCx803	100%	4V	4.1V	3.6V
UCCx804	50%	5V	12.5V	8.3V
UCCx805	50%	4V	4.1V	3.6V

BLOCK DIAGRAM

UDG92009-3

SLUS270C - MARCH 1999 - REVISED JANUARY 2005

ABSOLUTE MAXIMUM RATINGS (Note 1)

VCC Voltage (Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0V VCC Current (Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . 30.0mA OUT Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1.0A

OUT Energy (Capacitive Load) . . . . . . . . . . . . . . . . . . . 20.0 J Analog Inputs (FB, CS) . . . . . . . . . . . . . . . . . . . . –0.3V to 6.3V Power Dissipation at TA < +25°C (N or J Package) . . . . . 1.0W Power Dissipation at TA < +25°C (D Package). . . . . . . . 0.65W Power Dissipation at TA < +25°C (L Package) . . . . . . . 1.375W Storage Temperature Range. . . . . . . . . . . . . –65°C to +150°C Lead Temperature (Soldering, 10 Seconds) . . . . . . . . +300°C

Note 1: Values beyond which damage may occur. All voltages are with respect to GND. All currents are positive into the specified terminal. Consult Unitrode databook for information regarding thermal specifications and limitations of packages.

Note 2: In normal operation VCC is powered through a current limiting resistor. Absolute maximum of 12V applies when VCC is driven from a low impedance source such that ICC does not exceed 30mA (which includes gate drive current requirement). The resistor should be sized so that the VCC voltage, under operating conditions is below 12V but above the turn off threshold.

TEMPERATURE AND PACKAGE SELECTION

	Temperature Range	Available Packages
UCC180X	–55°C to +125°C	J, L
UCC280X	–40°C to +85°C	N, D, PW
UCC380X	0°C to +70°C	N, D, PW

ORDERING INFORMATION

UCC 80

PACKAGE

PRODUCT OPTION

TEMPERATURE RANGE

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

CONNECTION DIAGRAMS

TSSOP-8 (Top View)
PW Package
1	COMP	REF	8
2	FB	VCC	7
3	CS	OUT	6
4	RC	GND	5

DIL-8, SOIC-8 (Top View)

J or N, D Package

COMP				REF
	1		8
FB				VCC
	2		7
CS				OUT
	3		6
RC				GND
	4		5

	LCC-20	PACKAGE PIN FUNCTION
	(TOP VIEW)
		FUNCTION	PIN
	L Package
		N/C	1
		Comp	2
		N/C	3-4
		FB	5
		N/C	6
		CS	7
		N/C	8-9
		RC	10
		N/C	11
		PWR GND	12
		GND	13
		N/C	14
		OUT	15
		N/C	16
		VCC	17
		N/C	18-19
		REF	20

2

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

ELECTRICAL CHARACTERISTICSUnless otherwise stated, these specifications apply for –55°C ≤ TA ≤ +125°C for UCC180x; –40°C ≤ TA ≤ +85°C for UCC280x; 0°C≤ TA ≤ +70°C for UCC380x; VCC=10V (Note 3); RT=100k from REF to RC; CT=330pF from RC to GND; 0.1 F capacitor from VCC to GND; 0.1 F capacitor from VREF to GND. TA=TJ.

PARAMETER	TEST CONDITIONS	UCC180X			UCC380X			UNITS
		UCC280X
		MIN	TYP	MAX	MIN	TYP	MAX
Reference Section
Output Voltage	TJ=+25°C, I=0.2mA, UCCx800/1/2/4	4.925	5.00	5.075	4.925	5.00	5.075	V
	TJ=+25°C, I=0.2mA, UCCx803/5	3.94	4.00	4.06	3.94	4.00	4.06
Load Regulation	0.2mA<I<5mA		10	30		10	25	mV
Line Regulation	TJ=+25°C,			1.9			1.9	mV/V
	VCC=10V to Clamp (IVCC=25mA)
	TJ=–55°C to +125°C,			2.5			2.1	mV/V
	VCC=10V to Clamp (IVCC=25mA)
Total Variation	UCCx800/1/2/4 (Note 7)	4.88	5.00	5.10	4.88	5.00	5.10	V
	UCCx803/5 (Note 7)	3.90	4.00	4.08	3.90	4.00	4.08	V
Output Noise Voltage	10Hz ≤ f ≤ 10kHz, TJ=+25°C (Note 9)		130			130		V
Long Term Stability	TA=+125°C, 1000 Hours (Note 9)		5			5		mV
Output Short Circuit		–5		–35	–5		–35	mA
Oscillator Section
Oscillator Frequency	UCCx800/1/2/4 (Note 4)	40	46	52	40	46	52	kHz
	UCCx803/5 (Note 4)	26	31	36	26	31	36	kHz
Temperature Stability	(Note 9)		2.5			2.5		%
Amplitude peak-to-peak		2.25	2.40	2.55	2.25	2.40	2.55	V
Oscillator Peak Voltage			2.45			2.45		V
Error Amplifier Section
Input Voltage	COMP=2.5V; UCCx800/1/2/4	2.44	2.50	2.56	2.44	2.50	2.56	V
	COMP=2.0V; UCCx803/5	1.95	2.0	2.05	1.95	2.0	2.05
Input Bias Current		–1		1	–1		1	A
Open Loop Voltage Gain		60	80		60	80		dB
COMP Sink Current	FB=2.7V, COMP=1.1V	0.3		3.5	0.4		2.5	mA
COMP Source Current	FB=1.8V, COMP=REF–1.2V	–0.2	–0.5	–0.8	–0.2	–0.5	–0.8	mA
Gain Bandwidth Product	(Note 9)		2			2		MHz
PWM Section
Maximum Duty Cycle	UCCx800/2/3	97	99	100	97	99	100	%
	UCCx801/4/5	48	49	50	48	49	50
Minimum Duty Cycle	COMP=0V			0			0	%
Current Sense Section
Gain	(Note 5)	1.10	1.65	1.80	1.10	1.65	1.80	V/V
Maximum Input Signal	COMP=5V (Note 6)	0.9	1.0	1.1	0.9	1.0	1.1	V
Input Bias Current		–200		200	–200		200	nA
CS Blank Time		50	100	150	50	100	150	ns
Over-Current Threshold		1.42	1.55	1.68	1.42	1.55	1.68	V
COMP to CS Offset	CS=0V	0.45	0.90	1.35	0.45	0.90	1.35	V

3

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

ELECTRICAL CHARACTERISTICSUnless otherwise stated, these specifications apply for –55°C ≤ TA ≤ +125°C for UCC180x; –40°C ≤ TA ≤ +85°C for UCC280x; 0°C≤ TA ≤ +70°C for UCC380x; VCC=10V (Note 3); RT=100k from REF to RC; CT=330pF from RC to GND; 0.1 F capacitor from VCC to GND; 0.1 F capacitor from VREF to GND. TA=TJ.

PARAMETER				TEST CONDITIONS		UCC180X						UCC380X				UNITS
					UCC280X
Output Section
OUT Low Level		I=20mA, all parts					0.1		0.4				0.1		0.4	V
		I=200mA, all parts					0.35		0.90				0.35		0.90	V
		I=50mA, VCC=5V, UCCx803/5					0.15		0.40				0.15		0.40	V
		I=20mA, VCC=0V, all parts					0.7		1.2				0.7		1.2	V
OUT High VSAT		I=–20mA, all parts					0.15		0.40				0.15		0.40	V
(VCC-OUT)		I=–200mA, all parts					1.0		1.9				1.0		1.9	V
		I=–50mA,VCC=5V, UCCx803/5					0.4		0.9				0.4		0.9	V
Rise Time		CL=1nF					41		70				41		70	ns
Fall Time		CL=1nF					44		75				44		75	ns
Undervoltage Lockout Section
Start Threshold (Note 8)		UCCx800			6.6		7.2		7.8		6.6		7.2		7.8	V
		UCCx801			8.6		9.4		10.2		8.6		9.4		10.2	V
		UCCx802/4			11.5		12.5		13.5		11.5		12.5		13.5	V
		UCCx803/5			3.7		4.1		4.5		3.7		4.1		4.5	V
Stop Threshold (Note 8)		UCCx1800			6.3		6.9		7.5		6.3		6.9		7.5	V
		UCCx1801			6.8		7.4		8.0		6.8		7.4		8.0	V
		UCCx802/4			7.6		8.3		9.0		7.6		8.3		9.0	V
		UCCx803/5			3.2		3.6		4.0		3.2		3.6		4.0	V
Undervoltage Lockout Section (cont.)
Start to Stop Hysteresis		UCCx800			0.12		0.3		0.48		0.12		0.3		0.48	V
		UCCx801			1.6		2		2.4		1.6		2		2.4	V
		UCCx802/4			3.5		4.2		5.1		3.5		4.2		5.1	V
		UCCx803/5			0.2		0.5		0.8		0.2		0.5		0.8	V
Soft Start Section
COMP Rise Time		FB=1.8V, Rise from 0.5V to REF–1V					4		10				4		10	ms
Overall Section
Start-up Current		VCC < Start Threshold					0.1		0.2				0.1		0.2	mA
Operating Supply Current		FB=0V, CS=0V					0.5		1.0				0.5		1.0	mA
VCC Internal Zener Voltage		ICC=10mA (Note 8), (Note 10)			12		13.5		15		12		13.5		15	V
VCC Internal Zener Voltage Minus		UCCx802/4 (Note 8)			0.5		1.0				0.5		1.0			V
Start Threshold Voltage
Note 3: Adjust VCC above the start threshold before setting at 10V.
Note 4: Oscillator frequency for the UCCx800, UCCx802 and UCCx803 is the output frequency.
Oscillator frequency for the UCCx801, UCCx804 and UCCx805 is twice the output frequency.
Note 5: Gain is defined by: A =	∆ VCOMP			0 ≤VCS ≤ 0.8V.
	∆ VCS

Note 6: Parameter measured at trip point of latch with Pin 2 at 0V.

Note 7: Total Variation includes temperature stability and load regulation.

Note 8: Start Threshold, Stop Threshold and Zener Shunt Thresholds track one another. Note 9: Guaranteed by design. Not 100% tested in production.

Note 10: The device is fully operating in clamp mode as the forcing current is higher than the normal operating supply current.

4

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

PIN DESCRIPTIONS

	Unlike other devices, the error amplifier in the UCC3800
	family is a true, low output-impedance, 2MHz operational
	amplifier. As such, the COMP terminal can both source
	and sink current. However, the error amplifier is internally
	current limited, so that you can command zero duty cycle	UCCx800/1/2/4: F =		1.5
	by externally forcing COMP to GND.			R •C
	The UCC3800 family features built-in full cycle Soft Start.			10.
	Soft Start is implemented as a clamp on the maximum	UCCx803, UCCx805:
				F = R •C
	COMP voltage.
	CS: CS is the input to the current sense comparators.	where frequency is in Hz, resistance is in ohms, and ca-
	The UCC3800 family has two different current sense	pacitance is in farads. The recommended range of timing
	comparators: the PWM comparator and an over-current	resistors is between 10k and 200k and timing capacitor is
	comparator.	100pF to 1000pF. Never use a timing resistor less than
	The UCC3800 family contains digital current sense filter-	10k.
		To prevent noise problems, bypass VCC to GND with a
	ing, which disconnects the CS terminal from the current
	sense comparator during the 100ns interval immediately	ceramic capacitor as close to the VCC pin as possible.
	following the rising edge of the OUT pin. This digital filter-	An electrolytic capacitor may also be used in addition to
	ing, also called leading-edge blanking, means that in	the ceramic capacitor.
	most applications, no analog filtering (RC filter) is re-	REF: REF is the voltage reference for the error amplifier
	quired on CS. Compared to an external RC filter tech-	and also for many other functions on the IC. REF is also
	nique, the leading-edge blanking provides a smaller	used as the logic power supply for high speed switching
	effective CS to OUT propagation delay. Note, however,	logic on the IC.
	that the minimum non-zero On-Time of the OUT signal is	When VCC is greater than 1V and less than the UVLO
	directly affected by the leading-edge-blanking and the CS
	to OUT propagation delay.	threshold, REF is pulled to ground through a 5k ohm re-
		sistor. This means that REF can be used as a logic out-
	The over-current comparator is only intended for fault
		put indicating power system status. It is important for
	sensing, and exceeding the over-current threshold will	reference stability that REF is bypassed to GND with a
	cause a soft start cycle.	ceramic capacitor as close to the pin as possible. An
	FB: FB is the inverting input of the error amplifier. For	electrolytic capacitor may also be used in addition to the
	best stability, keep FB lead length as short as possible	ceramic capacitor. A minimum of 0.1µF ceramic is re-
	and FB stray capacitance as small as possible.	quired. Additional REF bypassing is required for external
	GND: GND is reference ground and power ground for all	loads greater than 2.5mA on the reference.
		To prevent noise problems with high speed switching
	functions on this part.
	OUT: OUT is the output of a high-current power driver ca-	transients, bypass REF to ground with a ceramic capaci-
		tor very close to the IC package.
	pable of driving the gate of a power MOSFET with peak
		VCC: VCC is the power input connection for this device.
	currents exceeding ± 750mA. OUT is actively held low
	when VCC is below the UVLO threshold.	In normal operation VCC is powered through a current
	The high-current power driver consists of FET output de-	limiting resistor.	Although quiescent VCC current is very
		low, total supply	current	will be higher, depending on
	vices, which can switch all of the way to GND and all of
		OUT current. Total VCC current is the sum of quiescent
	the way to VCC. The output stage also provides a very
		VCC current and the average OUT current. Knowing the
	low impedance to overshoot and undershoot. This means
		operating frequency and the MOSFET gate charge (Qg),
	that in many cases, external schottky clamp diodes are
		average OUT current can be calculated from:
	not required.
	COMP: COMP is the output of the error amplifier and the	performance, keep the timing capacitor lead to GND as
	input of the PWM comparator.	short and direct as possible. If possible, use separate

ground traces for the timing capacitor and all other functions.

The frequency of oscillation can be estimated with the following equations:

RC: RC is the oscillator timing pin. For fixed frequency operation, set timing capacitor charging current by connecting a resistor from REF to RC. Set frequency by connecting a timing capacitor from RC to GND. For best

IOUT = Qg × F.

There should be a minimum of 1.0 F in parallel with a 0.1 F ceramic capacitor from VCC to ground located close to the device

5

The UCC3800/1/2/3/4/5 oscillator generates a sawtooth waveform on RC. The rise time is set by the time constant of RT and CT. The fall time is set by CT and an internal transistor on-resistance of approximately 125 . During the fall time, the output is off and the maximum duty cycle is reduced below 50% or 100% depending on the part number. Larger timing capacitors increase the discharge time and reduce the maximum duty cycle and frequency.

Figure 1. Oscillator.

UCC1800/1/2/3/4/5

UCC2800/1/2/3/4/5

UCC3800/1/2/3/4/5

Figure 2. Error amplifier gain/phase response.

		4.00
		3.98
		3.96
		3.94
	(V)	3.92
	VREF
		3.90
		3.88

3.86

3.84

3.82

4

4.2

4.4

4.6

4.8

5

5.2

5.4

5.6

5.8

6

VCC (V)

Figure 3. UCC1803/5 VREF vs. VCC; ILOAD = 0.5mA.

Freq.(kHz)	1000
												100pF
Oscillator	100
												200pF
												330pF
												1nF
	10
	10			100									1000
									RT (k				)

Figure 4. UCC1800/1/2/4 oscillator frequency vs. RT and CT.

6

Freq.(kHz)	1000
Oscillator	100
												100pF
												200pF
												330pF
	10											1nF
	10			100									1000
									RT (k				)

Figure 5. UCC1803/5 oscillator frequency vs. RT and CT.

													UCC1800/1/2/3/4/5
													UCC2800/1/2/3/4/5
													UCC3800/1/2/3/4/5
	100
(%)	99.5
	99
Cycle
	98.5											T
														C
														T
	98											C		=
Duty
												=
	97.5
												C		100pF
												T
												=
Maximum												200pF
												330pF
	97
	96.5
	96
	95.5
	95
	10			100									1000

Oscillator Frequency (kHz)

Figure 6. UCC1800/2/3 maximum duty cycle vs. oscillator frequency.

Maximum Duty Cycle (%)

50

49.5

49

48.5

48

47.5

47

46.5

10

16

14

12

1nF

C

10V,

T

10

=

C

=

T

CC

=

(mA)

V

C

100pF

,1nF

T

8

=

=

8V

200pF

CC

330pF

CCI

V

6

, No Load

4

VCC

= 10V

2

VCC

= 8V,

No

Load

0

100

1000

0

100

200

300

400

500

600

700

800

900

1000

Oscillator

Frequency (kHz)

Oscillator Frequency (kHz)

Figure 7. UCC1801/4/5 maximum duty cycle vs. oscillator frequency.

Figure 8. UCC1800 ICC vs. oscillator frequency.

7