Richtek RT8203GA, RT8203PA Schematic [ru]

RT8203

High-Efficiency, Quad Output, Main Power-Supply Controllers for Notebook Computers

General Description

The RT8203 dual step-down, Switch Mode Power Supply (SMPS) controllers generate logic-supply voltages in battery-powered systems. The RT8203 include two pulsewidth modulation (PWM) controllers, adjustable from 2V to 5.5V or fixed at 5V and 3.3V. These devices feature two linear regulators providing 5V and 3.3V always-on outputs. Each linear regulator provides up to 100mA output current with automatic linear regulator bootstrapping to the main SMPS outputs. The RT8203 include on-board power-up sequencing, a power good (PGOOD) output, internal softstart, and soft-shutdown output discharge that prevents negative voltages on shutdown. Richtek's proprietary MachPWMTM “instant-on” response, constant on-time PWM control scheme operates without sense resistors and provides 100ns response to load transients while maintaining a relatively constant switching frequency. The unique ultrasonic mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications. Other features include diode-emulation, which maximizes efficiency in light-load applications, and fixed-frequency PWM mode, which reduces RF interference in sensitive applications. The RT8203 provides a pin-selectable switching frequency, allowing either 200kHz/300kHz or 400kHz/500kHz operation of the 5V/3.3V SMPSs, respectively. The RT8203 is available in SSOP-28 package.

Ordering Information

RT8203

Package Type

A : SSOP-28

Lead Plating System P : Pb Free

G : Green (Halogen Free and Pb Free)

Note :

Richtek products are :

`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.

`Suitable for use in SnPb or Pb-free soldering processes.

Features

zNo Current Sense Resistor Needed

z1.5% Output Voltage Accuracy

z3.3V and 5V 100mA Bootstrapped Linear Regulators

zInternal Soft-Start and Soft-Shutdown Output Discharge

zMach-PWM with 100ns Load Step Response

z3.3V and 5V Fixed or Adjustable Outputs

z7V to 24V Input Voltage Range

zUltrasonic Mode Operation 25kHz (min.)

zPower Good (PGOOD) Signal

zOver Voltage Protection

zUnder Voltage Protection

zOver Temperature Protection

zRoHS Compliant and 100% Lead (Pb)-Free

Applications

zNotebook and Subnotebook Computers

zPDAs and Mobile Communication Devices

z3- and 4-Cell Li+ Battery-Powered Devices

Pin Configurations

(TOP VIEW)

										BOOT3
		NC					28
PGOOD						2	27			PHASE3
		ON3				3	26			UGATE3
		ON5				4	25			LDO3
ILIM3						5	24			LGATE3
		EN				6	23			GND
		FB3				7	22			VOUT3
VREF						8	21			VOUT5
		FB5				9	20			VIN
		PRO				10	19			LGATE5
ILIM5						11	18			LDO5
	SKIP					12	17			VCC
		TON				13	16			UGATE5
BOOT5						14SSOP-2815				PHASE5

SSOP-28

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RT8203

Typical Application Circuit

5V

ALWAYS ON

C1

+

18

VIN

7V to 24V

4.7µF

C2

R1

R2

LDO5

1µF

47

3.9

17

VCC

ON3 3

VREF

5

ILIM3

ON5 4

VCC

VCC

C3

11

ILIM5

LDO3 25

R6

C4

3.3V ALWAYS ON

1µF

20

VIN

PRO

10

1M

4.7µF

RT8203

C5

BAT254

D2

0.1µF

ON

D1

EN 6

BAT254

R3

R4

OFF

2.2

14

BOOT5

BOOT3

28 2.2

C9

C7

C6

C8

0.1µF

10µF

10µF

0.1µF

UGATE3 26

Q2

Q1

16

UGATE5

VOUT5

L1

AO4702

AO4702

VOUT3

15

PHASE3 27

L2

5V

PHASE5

3.3V

C10

D3

BSC119N03

19

LGATE3 24

D4

C11

Q3

LGATE5

Q4

13

BSC119N03

SEE

TON

VOUT3 22

TABLE

21

VOUT5

SKIP 12

VCC

8

VREF

C12

FB3

7

9

FB5

NC 1

R5

0.22µF

23

GND

PGOOD 2

100k

Power-Good

INDICATOR

Frequency-dependent Components

VOUT5		VOUT3
TON = VCC	TON = GND	TON = VCC	TON = GND
f = 200kHz	f = 400kHz	f = 300kHz	f = 500kHz
L1 = 7.6μH	L1 = 5.6μH	L2 = 4.7μH	L2 = 3μH
C10 = 330μF	C10 = 150μF	C11 = 470μF	C11 = 220μF

Figure 1. Fixed Voltage Regulator

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DS8203-05 April 2011

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RT8203

5V

ALWAYS ON

C1

+

18

VIN

7V to 24V

4.7µF

C2

R1

R2

LDO5

1µF

47

3.9

17

VCC

ON3 3

VREF

5

ILIM3

ON5 4

VCC

VCC

C3

11

ILIM5

LDO3 25

R6

C4

3.3V ALWAYS ON

1µF

20

VIN

PRO

10

1M

4.7µF

RT8203

C5

BAT254

D2

0.1µF

ON

D1

EN 6

BAT254

R3

R4

OFF

2.2

14

BOOT5

BOOT3

28 2.2

C9

C7

C6

C8

0.1µF

10µF

10µF

0.1µF

UGATE3 26

Q2

Q1

16

UGATE5

VOUT5

L1

AO4702

AO4702

VOUT3

15

PHASE3 27

L2

5V

PHASE5

3.3V

C10

D3

BSC119N03

19

LGATE3 24

D4

C11

Q3

LGATE5

Q4

BSC119N03

13

SEE

TON

VOUT3 22

TABLE

21

VOUT5

R9

R7

FB3 7

6.5k

C13

15k

9

FB5

C14

SKIP 12

VCC

R10

0.1µF

0.1µF

R8

8

VREF

NC 1

10k

10k

C12

R5

0.22µF

23

GND

PGOOD 2

100k

Power-Good

INDICATOR

Frequency-dependent Components

VOUT5		VOUT3
TON = VCC	TON = GND	TON = VCC	TON = GND
f = 200kHz	f = 400kHz	f = 300kHz	f = 500kHz
L1 = 7.6μH	L1 = 5.6μH	L2 = 4.7μH	L2 = 3μH
C10 = 330μF	C10 = 150μF	C11 = 470μF	C11 = 220μF

Figure 2. Adjustable Voltage Regulator

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Functional Pin Description

Pin No.		Pin Name		Pin Function
1		NC		Connect to GND.
2		PGOOD		Power Good Open Drain Output. PGOOD is pulled low if either output is disable or is
				more than 8.75% below its normal value.
				VOUT3 Enable Input. The 3.3V SMPS is enable if ON3 is greater than the on level
3		ON3		and disable if ON3 is less than the off level. If ON3 is connected to VREF, the 3.3V
				SMPS starts after the 5V SMPS reached regulation(delay start). Force ON3 below the
				clear fault level to reset the fault latched.
				VOUT5 Enable Input. The 5V SMPS is enable if ON5 is greater than the on level and
4		ON5		disable if ON5 is less than the off level. If ON5 is connected to VREF, the 5V SMPS
				starts after the 3.3V SMPS reached regulation(delay start). Force ON5 below the clear
				fault level to reset the fault latched.
				VOUT3 Current Limit Adjustment. The GND-PHASE3 current limit threshold defaults
5		ILIM3		to 100mV if ILIM3 is tied to VCC. In adjustable mode, the current limit threshold is 1/10
				the voltage seen at ILIM3 over 0.5V to 3V range. The logic threshold for switch over to
				100mV default value is approximately VCC − 1V.
				Enable Control Input. The device enters its 15μA supply current shutdown mode if EN
				is less than the EN input falling edge trip level and does not restart until EN is greater
6		EN		than the EN input rising edge trip level. Connect EN to VIN for automatically startup.
				EN can be connected to VIN through a resistive voltage divider to implement a
				programmable undervoltage lockout.
7		FB3		VOUT3 Feedback Input. Connect FB3 to GND for fixed 3.3V operation. Connect FB3
				to a resistive voltage divider from VOUT3 to GND to adjust the output from 2V to 5.5V.
				2V Reference Output. Bypass to GND with a 0.22μF(MIN) capacitor. VREF can source
8		VREF		up to 100μA for external loads. Loading VREF degrades FBx and VOUTx accuracy
				according to the VREF load regulation error.
9		FB5		VOUT5 Feedback Input. Connect FB5 to GND for fixed 5V operation. Connect FB5 to
				a resistive voltage divider from VOUT5 to GND to adjust the output from 2V to 5.5V.
				Over Voltage and Under Voltage Fault Protection Enable/Disable. Connect			PRO	to
		PRO
10				VCC to disable Over Voltage and Under Voltage protection. Connect PRO to GND to
				enable Over Voltage and Under Voltage protection.
				VOUT5 Current Limit Adjustment. The GND − PHASE5 current limit threshold defaults
11		ILIM5		to 100mV if ILIM5 is tied to VCC. In adjustable mode, the current limit threshold is 1/10
				the voltage seen at ILIM5 over 0.5V to 3V range. The logic threshold for switch over to
				100mV default value is approximately VCC − 1V.
				Operation Mode Input Control. Connect SKIP to GND for diode-emulation mode
12		SKIP
				(DEM) or to VCC for CCM mode(fixed frequency). Connect to VREF or floating for
				ultrasonic mode.
13		TON		Frequency Select Input. Connect to VCC for 200kHz/300kHz operation and to GND
				for 400kHz/500kHz operation (VOUT5/VOUT3 switching frequency respectively).
14		BOOT5		Boost Capacitor Connection for 5V SMPS. Connect an external ceramic capacitor to
				PHASE5 and an external diode to LDO5.

	To be continued
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RT8203

	Pin No.	Pin Name	Pin Function
	15	PHASE5	Inductor Connection for 5V SMPS. PHASE5 is the internal lower supply rail for the
			UGATE5 high side gate driver, and the current sense input for the 5V SMPS.
	16	UGATE5	High Side N-MOSFET Floating Gate-Driver Output for VOUT5. Swings between
			PHASE5 and BOOT5.
	17	VCC	Analog Supply Voltage Input for the internal analog integrated circuit. Bypass to GND
			with a 1μF ceramic capacitor.
			5V Linear Regulator Output. LDO5 is the gate driver supply for the external
			MOSFETs. LDO5 can provide a total of 100mA, including the MOSFET gate-driver
	18	LDO5	requirements and external loads. If VOUT5 is greater than the LDO5 switchover
			threshold, the LDO5 regulator shuts down and LDO5 pin connects to VOUT5 through
			a 1.4Ω switch. Bypass a 4.7μF ceramic capacitor to GND.
	19	LGATE5	Low side N-MOSFET Gate-Drive Output for VOUT5. Swings between GND and
			LDO5.
	20	VIN	Power-Supply Input. VIN powers the LDO5/LDO3 linear regulators and is also used
			for PWM control circuits. Connect VIN to the battery input or the AC adapter output.
			VOUT5 Sense Input. Connect to the 5V output. VOUT5 is an input to the PWM control
	21	VOUT5	circuit. It also serves as the 5V feedback input in fixed-voltage mode. If VOUT5 is
			greater than the LDO5 switchover threshold, the LDO5 shuts down and LDO5
			connects to VOUT5 through 1.4Ω switch.
			VOUT3 Sense Input. Connect to the 3.3V output. VOUT3 is an input to the PWM
	22	VOUT3	control circuit. It also serves as the 3.3V feedback input in fixed voltage mode. If
			VOUT3 is greater than the LDO3 switchover threshold, the LDO3 shuts down and
			LDO3 connects to VOUT3 through 1.5Ω switch.
	23	GND	Analog and Power Ground.
	24	LGATE3	Low side N-MOSFET Gate-Drive Output for VOUT3. Swings between GND and
			LDO5.
			3.3V Linear Regulator Output. LDO3 can provide a total of 100mA to external loads. If
	25	LDO3	VOUT3 is greater than the LDO3 switchover threshold, the LDO3 regulator shuts
			down and LDO3 pin connects to VOUT3 through a 1.5Ω switch. Bypass a 4.7μF
			ceramic capacitor to GND.
	26	UGATE3	High Side N-MOSFET Floating Gate-Driver Output for VOUT3. Swings between
			PHASE3 and BOOT3.
	27	PHASE3	Inductor Connection for 3.3V SMPS. PHASE3 is the internal lower supply rail for the
			UGATE3 high side gate driver, and the current sense input for the 3.3V SMPS.
	28	BOOT3	Boost Capacitor Connection for 3.3V SMPS. Connect an external ceramic capacitor to
			PHASE3 and an external diode to LDO5.

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RT8203

Function Block Diagram

				VIN
								PGOOD
								GND
BOOT3		U3				U5		BOOT5
UGATE3	Driver						Driver	UGATE5
PHASE3								PHASE5
		L3	VOUT3		VOUT5	L5
LGATE3	Driver		PWM		PWM		Driver	LGATE5
			Controller		Controller
ILIM3								ILIM5
FB3								FB5
VOUT3								VOUT5
		+			4.65V	+
			2.93V			-	EN5
	EN3	-					LDO
								LDO5
							(5V)
LDO3	LDO		LDO5
	(3V)							VCC
ON3	Power Sequence			Thermal		2V
ON5								VREF
EN	Logic			Shutdown		Reference
PRO
VIN
				Ton				Ux
				1-SHOT
VOUTx				R	TRIG
			Ton	QN
On-time
					QN
Compute				TRIG

Min. Toff

1-SHOT

VREF	+		-
	GM		+
	-
			Comp
				25Khz
				Detector
	SS					Lx
	(internal)
FBx	+	OV
	-
PRO	1.1xVREF			Zero		SKIP
					-
			S1	Detector
	-	UV
			S2 Latch	Q	+	PHASEx
	+
	0.7xVREF			Current	+	ILIMx
	-			Limit -	-
	+			+
PGOOD	0.9xVREF
				PWM Controller

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RT8203

Absolute Maximum Ratings (Note 1)

z Input Voltage, VIN, EN to GND ------------------------------------------------------------------------------

−0.3V to 25V

z BOOTx to GND -------------------------------------------------------------------------------------------------

−0.3V to 30V

z PHASEx to BOOTx --------------------------------------------------------------------------------------------

−6V to 0.3V

z PHASEx to GND ------------------------------------------------------------------------------------------------

−1V to 25V

z VCC, LDOx, VOUTx, ONx, VREF, FBx,

−0.3V to 6V

SKIP,

PRO,

---------------------------PGOOD to GND

z UGATEx to PHASEx ------------------------------------------------------------------------------------------

−0.3V to (VBOOTx + 0.3V)

z ILIMx to GND ----------------------------------------------------------------------------------------------------

−0.3V to (VCC + 0.3V)

z LGATEx to GND ------------------------------------------------------------------------------------------------

−0.3V to (VLDO5 + 0.3V)

z TON toGND ------------------------------------------------------------------------------------------------------

−0.3V to 6V

z LDOx, VREF Short Circuit to GND -------------------------------------------------------------------------

Momentary

z LDOx Circuit (Internal Regulator) Continuous

-----------------------------------------------------------

100mA

z LDOx Circuit (Switchover to VOUTx) Continuous ------------------------------------------------------

200mA

z Power Dissipation, PD @ TA = 25°C

SSOP-28 --------------------------------------------------------------------------------------------------------

1.053W

z Package Thermal Resistance

(Note 2)

SSOP-28, θJA ----------------------------------------------------------------------------------------------------

95°C/W

z Junction Temperature ------------------------------------------------------------------------------------------

150°C

z Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------

260°C

z Storage Temperature Range ---------------------------------------------------------------------------------

–65°C to 150°C

z ESD Susceptibility (Note 3)

HBM (Human Body Mode) -----------------------------------------------------------------------------------

2kV

MM (Machine Mode) -------------------------------------------------------------------------------------------

200V

Recommended Operating Conditions (Note 4)

z Input Voltage, VIN -----------------------------------------------------------------------------------------------

7V to 24V

z Control Voltage, VCC -------------------------------------------------------------------------------------------

5V ± 5%

z Junction Temperature Range ---------------------------------------------------------------------------------

–10°C to 125°C

z Ambient Temperature Range ---------------------------------------------------------------------------------

–10°C to 85°C

Electrical Characteristics

(VIN = 12V, No load on LDOx, VOUTx and VREF, ONx = VCC, VEN = 5V, TA = 25°C, unless Otherwise specification)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Main SMPS Controllers

Input Voltage Range

VIN

LDO5 in regulation

7

--

24

V

VOUT3 Output Voltage in Fixed

VOUT3

VIN = 7V to 24V, FB3 = GND,

3.285

3.330

3.375

V

Mode

VSKIP = 5V

VOUT5 Output Voltage in Fixed

VOUT5

VIN = 8V to 24V, FB5 = GND,

4.975

5.059

5.125

V

Mode

V

= 5V

SKIP

Output Voltage in Adjustable Mode

VIN = 7V to 24V, either SMPS

1.975

2.00

2.025

V

Output Voltage Adjust Range

Either SMPS

2

--

5.5

V

FBx Adjustable-Mode Threshold

Dual-Mode comparator

0.12

--

0.22

V

Voltage

To be continued

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RT8203

Parameter	Symbol							Test Conditions							Min	Typ	Max	Unit
		Either SMPS, V											= 5V, 0 to 5A		--	−0.1	--
										SKIP
DC Load Regulation	VLOAD	Either SMPS, V											= GND, 0 to 5A		--	−1.5	--	%
										SKIP
		Either SMPS, V											= 2V, 0 to 5A		--	−1.7	--
											SKIP
Line Regulation	VLINE	Either SMPS, 7V< VIN <24V													---	0.005	--	%/V
Current-Limit Threshold		ILIMx = VCC, GND to PHASEx													90	100	110	mV
(Positive, Default)
Current-Limit Threshold		VILIMx = 0.5V, GND to PHASEx													40	50	60
		VILIMx = 1V, GND to PHASEx													90	100	110	mV
(Positive, Adjustable)
		VILIMx = 2V, GND to PHASEx													185	200	215
Zero-Current Threshold						= GND, ILIMx = VCC, GND − PHASEx									--	3	--	mV
		SKIP
Soft-Start Ramp Time		Zero to full limit													--	1.5	---	ms
		VTON = 5V,							5V SMPS						--	200	--
		V					= VCC
									3.3V SMPS						--	300	--
				SKIP
Operating Frequency	fOSC																	kHz
		VTON = GND							5V SMPS						--	400	--
		V					= VCC
					SKIP				3.3V SMPS						--	500	--
						= VREF									25	--	--
			SKIP
		VTON = 5V							VOUT5 = 5.05V						1.854	2.060	2.265
On-Time Pulse Width									VOUT3 = 3.33V						0.821	0.912	1.003	μs
		V					= GND		VOUT5 = 5.05V						0.876	1.030	1.184
			TON
									VOUT3 = 3.33V						0.467	0.546	0.625
Minimum Off-time	tOFF														300	400	500	ns
		VTON = 5V							VOUT5 = 5.05V						--	92	--
Maximum Duty Cycle									VOUT3 = 3.33V						--	88	--	%
		VTON = GND							VOUT5 = 5.05V						--	84	--
									VOUT3 = 3.33V						--	80	--
Internal Regulator And Reference Voltage
LDO5 Output Voltage		ONx = GND, 7V < VIN < 24V,													4.90	5.0	5.10	V
		0 < ILDO5 < 100mA												(Note 5)
LDO5 Short-Circuit Current		LDO5 = GND													--	350	--	mA
VCC Under-Voltage		Falling edge of VCC,													3.95	4.25	4.55	V
Lockout Fault Threshold		hysteresis = 1%
LDO5 Bootstrap Switch		Falling edge of VOUT5, rising edge at													4.52	4.65	4.78	V
Threshold		VOUT5 regulation point
LDO5 Bootstrap Switch		LDO5 to VOUT5, VOUT5 = 5V													--	1.4	3.2	Ω
Resistance
LDO3 Output Voltage		ONx = GND, 7V < VIN < 24V,													3.28	3.35	3.42	V
		0 < ILDO3 < 100mA												(Note 5)
LDO3 Short-Circuit Current		LDO3 = GND													--	175	--	mA
LDO3 Bootstrap Switch		Falling edge of VOUT3, rising edge at													2.82	2.93	3.04	V
Threshold		VOUT3 regulation point
																	To be continued
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