Texas Instruments UCC3810N, UCC3810DWTR, UCC3810DW, UCC2810N, UCC2810DWTR Datasheet

UCC1810

UCC2810

UCC3810

Dual Channel Synchronized Current Mode PWM

FEATURES

∙Single Oscillator Synchronizes Two PWMs

∙150A Startup Supply Current

∙2mA Operating Supply Current

∙Operation to 1MHz

∙Internal Soft Start

∙Full-Cycle Fault Restart

∙Internal Leading Edge Blanking of the Current Sense Signal

∙1 Amp Totem Pole Outputs

∙75ns Typical Response from Current Sense to Output

∙1.5% Tolerance Voltage Reference

DESCRIPTION

The UCC3810 is a high-speed BiCMOS integrated circuit which implements two synchronized pulse width modulators for use in off-line and DC-to-DC power supplies.

The UCC3810 provides perfect synchronization between two PWMs by using the same oscillator. The oscillator’s sawtooth waveform can be used for slope compensation if required.

Using a toggle flip flop to alternate between modulators, the UCC3810 ensures that one PWM will not slave, interfere, or otherwise affect the other PWM. This toggle flip flop also ensures that each PWM will be limited to 50% maximum duty cycle, insuring adequate off-time to reset magnetic elements.

This IC contains many of the same elements of the UC3842 current mode controller family, combined with the enhancements of the UCC3802. This minimizes power supply parts count. Enhancements include leading edge blanking of the current sense signals, full cycle fault restart, CMOS output drivers, and outputs which remain low even when the supply voltage is removed.

BLOCK DIAGRAM

UDG-92062-1

02/99

ABSOLUTE MAXIMUM RATINGS

VCC Voltage (Note 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11V VCC Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mA OUT1, OUT2 Current, Peak, 5% Duty Cycle. . . . . . . . . . . . ±1A

OUT1, OUT2 Energy (Capacitive Load) . . . . . . . . . . . . . . 20μJ Analog Inputs (FB1, FB2, CS1, CS2, SYNC). . . . –0.3V to 6.3V Operating Junction Temperature . . . . . . . . . . . . . . . . . . +150°C Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . 300°C

Note 1: All voltages are with respect to GND. All currents are positive into the specified terminals.

Note 2: Consult Unitrode Integrated Circuits Product & Applications Handbook for information regarding thermal specifications and limitations of packages.

Note 3: In normal operation, VCC is powered through a current limiting resistor. Absolute maximum of 11V applies when driven from a low impedance such that the VCC current does not exceed 20mA.

UCC1810

UCC2810

UCC3810

CONNECTION DIAGRAM

DIL-16, SOIC-16 (TOP VIEW)

J or N Package, DW Package

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for –55°C ≤ TA ≤ 125°C for UCC1810; –40°C ≤ TA ≤ 85°C for UCC2810; 0°C ≤ TA ≤ 70°C for UCC3810; V CC = 10V (Note 4); RT = 150k; CT = 120pF; No Load; TA = TJ. All parameters are the same for both channels.

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
Reference Section
Output Voltage	TJ = 25°C	4.925	5.000	5.075	V
Load Regulation	0mA < IREF < 5mA		5	25	mV
Line Regulation	UVLO Stop Threshold Voltage +0.5V < VCC < Shunt		12		mV
	Voltage
Output Voltage	Full temperature range, 0mA < IREF < 5mA	4.85	5.00	5.10	V
Output Noise Voltage	10Hz < f < 10kHz, TJ = +25°C (Note 10)		235		μV
Long Term Stability	TA = +125°C, 1000 Hours (Note 10)		5		mV
Output Short Circuit Current			–8	–25	mA
Oscillator Section
Oscillator Frequency	RT = 30k, CT = 120pF (Note 5)	840	940	1040	kHz
Oscillator Frequency	RT = 150k, CT = 120pF (Note 5)	200	220	240	kHz
Temperature Stability	(Note 10)		2.5		%
Peak Voltage			2.5		V
Valley Voltage			0.05		V
Peak-to-Peak Amplitude		2.25	2.45	2.65	V
SYNC Threshold		0.80	1.65	2.2	V
SYNC Input Current	SYNC = 5V		30		μA
Error Amplifier Section
FB Input Voltage	COMP = 2.5V	2.44	2.50	2.56	V
FB Input Bias Current				±1	μA
Open Loop Voltage Gain		60	73		dB
Unity Gain Bandwidth	(Note 10)		2		MHz
COMP Sink Current	FB = 2.7V, COMP = 1V	0.3	1.4	3.5	mA
COMP Source Current	FB = 1.8V, COMP = 4V	–0.2	–0.5	–0.8	mA
Minimum Duty Cycle	COMP = 0V			0	%
COMP Soft Start Rise Time	FB = 1.8V, Rise from 0.5V to REF–1.5V		5		ms

2

UCC1810

UCC2810

UCC3810

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for –55°C ≤ TA ≤ 125°C for UCC1810; –40°C ≤ TA ≤ 85°C for UCC2810; 0°C ≤ TA ≤ 70°C for UCC3810; V CC = 10V (Note 4); RT = 150k; CT = 120pF; No Load; TA = TJ. All parameters are the same for both channels.

PARAMETER	TEST CONDITIONS					MIN	TYP	MAX	UNITS
Current Sense Section
Gain	(Note 6)					1.20	1.55	1.80	V/V
Maximum Input Signal	COMP = 5V (Note 7)					0.9	1.0	1.1	V
CS Input Bias Current								± 200	nA
CS to OUT Propagation Delay	CS steps from 0V to 1.2V, COMP = 2.5V						75		ns
CS Blank Time	(Note 8)						55		ns
CS Overcurrent Threshold						1.35	1.55	1.85	V
COMP to CS Offset	CS = 0V					0.65	0.95	1.4	V
PWM Section
Maximum Duty Cycle	RT = 150k, CT = 120pF (Note 10)					45	49	50	%
Maximum Duty Cycle	RT = 30k, CT = 120pF (Note 10)					40	45	48	%
Minimum On Time	CS =1.2V, COMP = 5V						130		ns
Output Section
OUT Low Level	IOUT = 20mA						0.12	0.42	V
	IOUT = 200mA						0.48	1.10	V
	IOUT = 20mA, VCC = 0V						0.7	1.20	V
OUT High Level	IOUT = –20mA						0.15	0.42	V
(VCC - OUT)	IOUT = –200mA						1.20	2.30	V
OUT Rise Time	COUT = 1nF						20	50	ns
OUT Fall Time	COUT = 1nF						30	60	ns
Undervoltage Lockout Section
Start Threshold						9.9	11.3	13.2	V
Stop Threshold						7.5	8.3	9.5	V
Start to Stop Hysteresis						1.7	3.0	4.7	V
ENABLE2 Input Bias Current	ENABLE2 = 0V					–20	–35	–55	μA
ENABLE2 Input Threshold						0.80	1.53	2.00	V
Voltage
Overall Section
Startup Current	VCC < Start Threshold Voltage						0.15	0.25	mA
Operating Supply Current,	VCC = 10V, FB = 2.75V						2.0	3.0	mA
Outputs Off
Operating Supply Current,	VCC = 10V, FB = 0V, CS = 0V, RT = 150k						3.2	5.1	mA
Outputs On
Operating Supply Current,	VCC = 10V, FB = 0V, CS = 0V, RT = 30k						8.5	14.5	mA
Outputs On
VCC Internal Zener Voltage	ICC = 10mA (Note 9)					11.0	12.9	14.0	V
VCC Internal Zener Voltage Minus						0.4	1.2		V
Start Threshold Voltage
Note 4: Adjust VCC above the start threshold before setting at 10V.				4
Note 5: Oscillator frequency is twice the output frequency.		FOSC ≈
		RT ×CT

Note 6: Current Sense Gain A is defined by: A = VCOMP 0 ≤ VCS ≤ 08.V . VCS

Note 7: Parameter measured at trip point of latch with FB = 0V.

Note 8: CS Blank Time is measured as the difference between the minimum non-zero on-time and the CS to OUT delay. Note 9: Start Threshold Voltage and VCC Internal Zener Voltage track each other.

Note 10: Guaranteed by design. Not 100% tested in production.

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