Texas Instruments UC3860QTR, UC3860Q, UC3860N, UC3860DWTR, UC3860DW Datasheet

UC1860

UC2860

UC3860

Resonant Mode Power Supply Controller

FEATURES

∙3MHz VFO Linear over 100:1 Range

∙5MHz Error Amplifier with Controlled Output Swing

∙Programmable One Shot Timer— Down to 100ns

∙Precision 5V Reference

∙Dual 2A Peak Totem Pole Outputs

∙Programmable Output Sequence

∙Programmable Under Voltage Lockout

∙Very Low Start Up Current

∙Programmable Fault Management & Restart Delay

∙Uncommitted Comparator

DESCRIPTION

The UC1860 family of control ICs is a versatile system for resonant mode power supply control. This device easily implements frequency modulated fixed-on-time control schemes as well as a number of other power supply control schemes with its various dedicated and programmable features.

The UC1860 includes a precision voltage reference, a wide-bandwidth error amplifier, a variable frequency oscillator operable to beyond 3MHz, an oscillator-triggered one-shot, dual high-current totem-pole output drivers, and a programmable toggle flip-flop. The output mode is easily programmed for various sequences such as A, off, B, off; A & B, off; or A, B, off. The error amplifier contains precision output clamps that allow programming of minimum and maximum frequency.

The device also contains an uncommitted comparator, a fast comparator for fault sensing, programmable soft start circuitry, and a programmable restart delay. Hic-up style response to faults is easily achieved. In addition, the UC1860 contains programmable under voltage lockout circuitry that forces the output stages low and minimizes supply current during start-up conditions.

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (pin 19) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V Output Current, Source or Sink (pins 17 & 20)

DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8A Pulse (0.5μs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0A Power Ground Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.2V

Inputs (pins 1, 2, 3, 4, 8, 9, 11, 12,

13, 14, 21, 22, 23 & 24) . . . . . . . . . . . . . . . . . . . . . . -0.4 to 6V Error Amp Output Current, Source or Sink (pin 5) . . . . . . . . 2mA IVFO Current (pin 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2mA Comparator Output Current (pin 15) . . . . . . . . . . . . . . . . . . 5mA

Comparator Output Voltage (pin 15) . . . . . . . . . . . . . . . . . . 15V Soft Start or Restart Delay Sink Current (pins 22 & 23) . . . 5mA Power Dissipation at TA = 50°C (DIP) . . . . . . . . . . . . . . . 1.25W Power Dissipation at TA = 50°C (PLCC) . . . . . . . . . . . . . . . . 1W Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . . 300°C

Note: All voltages are with respect to signal ground and all currents are positive into the specified terminal.

Pin numbers refer to the DIP.

Refer to Packaging Section of Databook for thermal limitations and considerations of packages.

BLOCK DIAGRAM

10/93

UC1860

UC2860

UC3860

CONNECTION DIAGRAM

DIL - 24 (TOP VIEW)

J or N Package

PLCC-28, LCC-28 (TOP VIEW)

Q or L Package

PIN PACKAGE FUNCTION

FUNCTION	PIN
S GND	1
IVFO	2
CVFO	3
RC	4
VREF	5
CMP IN (-)	6
CMP IN (+)	7
TRIG	8
OSC DSBL	9
CMP OUT	10
N/C	11, 12
OUT A	13
PGND	14
N/C	15
VCC	16
OUT B	17
N/C	18, 19
MODE	20
SFT STRT	21
RST DLY	22
UVLO	23
FLT (-)	24
FLT (+)	25
EA IN (+)	26
EA IN (-)	27
EA OUT	28

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, all specifications apply for -55°C ≤ TA ≤ 125°C for the UC1860, -25°C ≤ TA ≤ 85°C for the UC2860, 0 ≤ TA ≤ 70°C for the UC3860, VCC = 12V, CVFO = 330pF, IVFO = 0.5mA, C = 330pF, and R = 2.7k, TA = TJ.

PARAMETER	CONDITIONS	MIN	TYP	MAX	UNITS
Reference Section
Output Voltage	TA = 25°C, I O = 0	4.95	5.00	5.05	V
	IO = 0, Over Temp	4.93		5.07	V
Line Regulation	10 ≤ VCC ≤ 20V		2	15	mV
Load Regulation	0≤ IO ≤ 10mA		2	25	mV
Output Noise Voltage*	10Hz ≤ f ≤ 10kHz		50		μVRMS
Short Circuit Current	VREF = 0V	-150		-15	mA
Error Amplifier Section
Input Offset Voltage	2.8 ≤ VCM ≤ 4.5V		1	8	mV
Input Bias Current			50	500	nA
Open Loop Gain	dVO = 1.5V	60	80		dB
PSRR	10 ≤ VCC ≤ 20V	70	100		dB
Output Low (VO-VIVFO)	-0.1 ≤ IO ≤ 0.1mA	-8	0	8	mV
Output High (VO-VIVFO)	-0.5 ≤ IO ≤ 0.5mA	1.9	2	2.1	V
Unity Gain Bandwidth*	RIN = 2k	4	5		MHz
Oscillator Section
Nominal Frequency*		1.0	1.5	2.0	MHz
dF/dIOSC*	100 ≤ IVFO ≤ 500μA	2	3	4	GHz/A

*Guaranteed by design but not 100% tested.

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UC1860

UC2860

UC3860

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, all specifications apply for -55°C ≤ TA ≤ 125°C for the UC1860, -25° ≤ TA ≤ 85°C for the UC2860, 0 ≤ TA ≤ 70°C for the UC3860, V CC = 12V, CVFO = 330pF, IVFO = 0.5mA, C = 330pF, and R = 2.7k, TA = TJ.

PARAMETER	CONDITIONS	MIN	TYP	MAX	UNITS
Oscillator Section (cont’d)
Trig in Threshold		1.0	1.4	1.8	V
Trig in Open Circuit Voltage		0.7	0.9	1.1	V
Trig in Delta (VTH-VOC)		0.3	0.5	0.7	V
Trig in Input Resistance	dV TRIG = VOC to VTH	5	12	25	kΩ
Minimum Trig in Pulse Width*			3	10	ns
Osc. Disable Threshold		1.0	1.4	1.8	V
One Shot Timer
On Time*		150	200	250	ns
Clamp Frequency*	IVFO = 1.5mA	2.8	3.7	4.6	MHz
Dead Time*	IVFO =1.5mA	35	70	100	ns
Output Stage
Output Low Saturation	20mA		0.2	0.4	V
	200mA		0.5	2.2	V
Output High Saturation	-20mA		1.5	2.0	V
	-200mA		1.7	2.5	V
Rise/Fall Time*	CLOAD = 1nF		15	30	ns
UVLO Low Saturation	20mA		0.8	1.5	V
Output Mode Low Input				0.4	V
Output Mode High Input		2.0			V
Under Voltage Lockout Section
VCC Comparator Threshold	On	16	17.3	18.5	V
	Off	9.5	10.5	12	V
UVLO Comparator Threshold	On	3.6	4.2	4.8	V
	Hysteresis	0.2	0.4	0.6	V
UVLO Input Resistance	UVLO = 4/VCC = 8	10	23	50	kΩ
VREF Comparator Threshold	VCC = UVLO = VREF		4.5	4.9	V
Supply Current
ICC	VCC = 12V, VOSC DSBL = 3V		30	40	mA
ISTART	UVLO pin open		0.3	0.5	mA
	VCC = VCC (on) -0.3V
Fault Comparator
Input Offset Voltage	−0.3 ≤ VCM ≤ 3V		2	10	mV
Input Bias Current	VCM = 0V		100	200	μA
Input Offset Current	VCM = 0V		10	30	μA
Propagation Delay To Output*	±50mV input		100	150	ns
Uncommitted Comparator
Input Offset Voltage	-0.3 ≤ VCM ≤ 3V		2	10	mV
Input Bias Current	VCM = 0V		100	200	μA
Input Offset Current	VCM = 0V		10	30	μA
Output Low Voltage	IO = 2mA		0.3	0.5	V
Propagation Delay To Sat*	±50mV input, 2.5k load to 5V		50	100	ns
Soft Start/Restart Control Section
Saturation Voltage (2 pins)	ISINK = 100μA		0.2	0.5	V
Charge Current (2 pins)		2	5	10	μA
Restart Delay Threshold		2.8	3.0	3.2	V

*Guaranteed by design but not 100% tested.

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