Richtek RT8207GQW Schematic [ru]

General Description

The RT8207 provides a complete power supply for both DDRII/DDRIII memory systems. It integrates a synchronous PWM buck controller with a 3A sink/source tracking linear regulator and a buffered low noise reference.

The PWM controller provides the high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate low voltage chipset RAM supplies in notebook computers. The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency.

The RT8207 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The buck conversion allows this device to directly step down high-voltage batteries for the highest possible efficiency.

The 3A sink/source LDO maintains fast transient response only requiring 20μF of ceramic output capacitance. In addition, the LDO supply input is available externally to significantly reduce the total power losses. The RT8207 supports all of the sleep state controls placing VTT at High-Z in S3 and discharging VDDQ, VTT and VTTREF (soft-off) in S4/S5.

RT8207

Complete DDRII/DDRIII Memory Power Supply Controller

Features

z PWM Controller

` Resistor Programmable Current Limit by Low-Side RDS(ON) Sense

` Quick Load-Step Response within 100ns ` 1% VOUT Accuracy Over Line and Load

` Fixed 1.8V (DDRII), 1.5V (DDRIII) or Adjustable 0.75V to 3.3V Output Range

` Battery Input Range 2.5V to 26V

` Resistor Programmable Frequency ` Over/Under Voltage Protection

` 4 Steps Current Limit During Soft-Start

` Drives Large Synchronous-Rectifier FETs ` Power-Good Indicator

z 3A LDO (VTT), Buffered Reference (VTTREF) ` Capable to Sink and Source Up to 3A

` LDO Input Available to Optimize Power Losses ` Requires Only 20μF Ceramic Output Capacitor ` Buffered Low Noise 10mA VTTREF Output

` Accuracy ±20mV for Both VTTREF and VTT ` Supports High-Z in S3 and Soft-Off in S4/S5

z RoHS Compliant and Halogen Free

Applications

z DDRII/DDRIII Memory Power Supplies

z Notebook Computers

z SSTL18, SSTL15 and HSTL Bus Termination

	The RT8207 has all of the protection features including	Pin Configurations
	thermal shutdown and is available in the WQFN-24L 4x4			(TOP VIEW)
	package.		VTT	VLDOIN	BOOT	UGATE	PHASE	LGATE
	Ordering Information
			24	23	22	21	20	19
	RT8207
		VTTGND	1					18	PGND
	Package Type	VTTSNS	2					17	NC
		GND	3		GND			16	CS
		MODE	4					15	VDDP
	QW : WQFN-24L 4x4 (W-Type)
		VTTREF	5				25	14	VDD
	Lead Plating System	DEM	6					13	PGOOD
			7	8	9	10	11	12
	G : Green (Halogen Free and Pb Free)
	Note :		NC	VDDQ	FB	S3	S5	TON
	Richtek products are :
				WQFN-24L 4x4
	` RoHS compliant and compatible with the current require-
	ments of IPC/JEDEC J-STD-020.
	` Suitable for use in SnPb or Pb-free soldering processes.

DS8207-07 March 2011

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RT8207

Marking Information

For marking information, contact our sales representative directly or through a Richtek distributor located in your area.

Typical Application Circuit

			12	RT8207
				TON	BOOT
			15
VDDP				VDDP
5V					UGATE
	C1	R1
		5.1
	1µF		14	VDD	PHASE
		C2
			R3		LGATE
		1µF
	R2
			5.6k
	100k		16	CS
			13
PGOOD				PGOOD	FB
VTT/VTTREF Control			10	S3
			11
	VDDQ Control			S5	VLDOIN
			4
	Discharge Mode			MODE	VDDQ
			6
	CCM/DEM			DEM	VTT
	3 , Exposed Pad (25)
				GND	VTTSNS
			18
				PGND
			1		VTTREF
				VTTGND

			V
			IN
	R4		2.5V to 26V
	620k
	R5		C9
			10µF x 3
22	0
			C4			V
			0.1µF			VDDQ
						1.2V
21	R6	0	Q1
			BSC09	L1
20			4N035	1µH
19				R7		C7
			Q2			220µF
	BSC032N035			C5	R8	C6
					6k
9
					R9	C9
23					10k	0.1µF
8
24
2			C8
			10µF x 2
5
			C3
			33nF

Figure A. Adjustable Voltage Regulator

			12
	VDDP		15
	5V	R1
	C1
		5.1
	1µF		14
		C2	R3
	R2	1µF
			5.6k
	100k		16
	PGOOD		13
	VTT/VTTREF Control		10
			11
	VDDQ Control
			4
	Discharge Mode
			6
	CCM/DEM
		, Exposed Pad (25)
	3
			18
			1

					V
					IN	26V
				R4	2.5V to
				620k
				R5		C8
	RT8207					10µF x 2
			22	0	C4
	TON	BOOT					V
					0.1µF		VDDQ
	VDDP					Q1	1.8V/1.5V
			21	R6	0
		UGATE
						BSC09	L1
	VDD	PHASE	20			4N035	1µH
			19				C6
		LGATE				R7
					Q2		220µF
					BSC032N035	C5
	CS
	PGOOD	VDDQ	8
			23
	S3	VLDOIN
	S5	VTT	24
			2		C7
	MODE	VTTSNS
					10µF x 2
			5
	DEM	VTTREF
					C3
	GND
					33nF
	PGND	FB	9		VDDP for DDRII
	VTTGND				GND for DDRIII

	Figure B. Fixed Voltage Regulator
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RT8207

Function Block Diagram

TRIG

VDDQ

On-time

Compute

TON

1-SHOT

R

BOOT

+

Comp

-GM

-

S

Q

PWM

DRV

UGATE

+

-

+

Min. TOFF

PHASE

VREF 0.75V

Q

TRIG

VDDP

Latch

1-SHOT

+

OV

115% VREF

S1

Q

DRV

LGATE

-

FB

-

UV

Latch

PGND

70% VREF

S1

Q

Diode

+

-

Emulation

90% VREF

+

Thermal

+

-

CS

VDD

SS Timer

GM

Shutdown

-

+

S5

VDD

10µA

PWM

DEM

PGOOD

S3

Discharge

VTTREF

Mode

MODE

VLDOIN

Select

+

-

+

-

+

VTT

-

+

-

VTTSNS

110% VVTTREF

-

+

GND

90% VVTTREF

-

+

VTTGND

DS8207-07

March

2011

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RT8207

Functional Pin Description

	Pin No.	Pin Name	Pin Function
	1	VTTGND	Power Ground for the VTT_LDO.
	2	VTTSNS	Voltage Sense Input for the VTT_LDO. Connect to the terminal of the VTT_LDO
			output capacitor
	3,	GND	Analog Ground. The exposed pad must be soldered to a large PCB and
	25 (Exposed Pad)		connected to GND for maximum power dissipation.
	4	MODE	Output Discharge Mode Setting Pin. Connect to VDDQ for tracking discharge.
			Connect to GND for non-tracking discharge. Connect to VDD for no discharge.
	5	VTTREF	VTTREF Buffered Reference Output.
	6	DEM	Diode-Emulation Mode Enable Pin. Connect to VDD will enable diode-emulation
			mode. Connect to GND will always operate in forced CCM mode.
	7, 17	NC	No Internal Connection.
			VDDQ Reference Input for VTT and VTTREF. Discharge current sinking terminal
	8	VDDQ	for VDDQ non-tracking discharge. Output voltage feedback input for VDDQ
			output if FB pin is connected to VDD or GND
			VDDQ Output Setting Pin. Connect to GND for DDRIII (VDDQ = 1.5V) power
	9	FB	supply. The pin should be connect to VDD for DDRII (VDDQ = 1.8V) power supply
			or be connected to a resistive voltage divider from VDDQ to GND to adjust the
			output of PWM from 0.75V to 3.3V.
	10	S3	S3 Signal Input.
	11	S5	S5 Signal Input
	12	TON	The pin is used to set the UGATE on time through a pull-up resistor connecting to
			VIN.
	13	PGOOD	Power-Good Open-Drain Output. This pin will be in HIGH state when VDDQ
			output voltage is within the target range.
	14	VDD	Supply Input for the Analog Supply.
	15	VDDP	Supply Input for the Low Gate Driver.
	16	CS	Current Limit Threshold Setting Input. Connect this pin to VDD through the
			voltage setting resistor.
	18	PGND	Power Ground for Low-Side MOSFET.
	19	LGATE	Low-Side Gate Driver Output for VDDQ.
	20	PHASE	External Inductor Connection for VDDQ and it behaves as the current sense
			comparator input for Low-Side MOSFET RDS(ON) sensing.
	21	UGATE	High-Side Gate Driver Output for VDDQ.
	22	BOOT	Boost Flying Capacitor Connection for VDDQ.
	23	VLDOIN	Power Supply for the VTT_LDO.
	24	VTT	Power Output for the VTT_LDO

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							RT8207
Absolute Maximum Ratings (Note 1)
z Input Voltage, TON to GND ----------------------------------------------------------------------------------------------							–0.3V to 32V
z BOOT to GND --------------------------------------------------------------------------------------------------------------							–0.3V to 38V
z PHASE to GND
DC-----------------------------------------------------------------------------------------------------------------------------							−0.3V to 32V
<20ns ------------------------------------------------------------------------------------------------------------------------							−8V to 38V
z PHASE to BOOT ----------------------------------------------------------------------------------------------------------							–6V to 0.3V
z VDD, VDDP, CS, MODE, S3, S5, VTTSNS, VDDQ, DEM to GND --------------------------------------------							–0.3V to 6V
z VTTREF, VTT, VLDOIN, FB, PGOOD to GND ----------------------------------------------------------------------							–0.3V to 6V
z UGATE to PHASE
DC-----------------------------------------------------------------------------------------------------------------------------							−0.3V to 6V
<20ns ------------------------------------------------------------------------------------------------------------------------							−5V to 7.5V
z LGATE to GND
DC-----------------------------------------------------------------------------------------------------------------------------							−0.3V to 6V
<20ns ------------------------------------------------------------------------------------------------------------------------							−2.5V to 7.5V
z PGND, VTTGND toGND -------------------------------------------------------------------------------------------------							–0.3V to 0.3V
z Power Dissipation, PD @ TA = 25°C
WQFN-24L 4x4 -----------------------------------------------------------------------------------------------------------							1.923W
z Package Thermal Resistance (Note 2)
WQFN-24L 4x4, θJA -------------------------------------------------------------------------------------------------------							52°C/W
WQFN-24L 4x4, θJC	------------------------------------------------------------------------------------------------------						7°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 ----------------------------------------------------------------------------------------------------------							2.5V to 26V
z Control Voltage, VDDP, VDD ----------------------------------------------------------------------------------------------							4.5V to 5.5V
z Junction Temperature Range --------------------------------------------------------------------------------------------							−40°C to 125°C
z Ambient Temperature Range --------------------------------------------------------------------------------------------							−40°C to 85°C
Electrical Characteristics
(VDDP = VDD = 5V, VIN = 15V, DEM = VDD , RTON = 1MΩ, TA = 25°C, unless otherwise specified)
Parameter		Symbol		Test Conditions	Min	Typ	Max		Unit
PWM Controller
Quiescent Supply Current				FB forced above the regulation point,	--	470	1000		μA
(VDD + VDDP)				VS5 = 5V, VS3 = 0V
TON Operating Current				RTON = 1MΩ	--	15	--		μA
IVLDOIN BIAS Current				VS5 = VS3 = 5V, VTT = No Load	--	1	--		μA
IVLDOIN Standby Current				VS5 = 5V, VS3= 0, VTT = No Load	--	0.1	10		μA
							To be continued
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RT8207

Parameter	Symbol	Test Conditions	Min	Typ	Max	Unit
		VDD + VDDP	--	0.1	10
Shutdown current		TON	--	0.1	5	μA
(VS5 = VS3 = 0V)		S3/S5/DEM = 0V	−1	0.1	1
		IVLDOIN	--	0.1	1
FB Reference Voltage	VREF	VDD = 4.5V to 5.5V	0.742	0.75	0.758	V
Fixed VDDQ Output Voltage		FB = GND	--	1.5	--	V
		FB = VDD	--	1.8	--
FB Input Bias Current		FB = 0.75V	−1	0.1	1	μA
VDDQ Voltage Range			0.75	--	3.3	V
On-Time, VIN = 15V		RTON = 1MΩ	267	334	401	ns
Minimum Off-Time			250	400	550	ns
VDDQ Input Resistance			--	100	--	kΩ
VDDQ Shutdown Discharge		VS5 = GND	--	15	--	Ω
Resistance
Current Sensing
CS Sink Current		VCS > 4.5V, After UV Blank Time	9	10	11	μA
Current Comparator Offset		GND − PHASE	−15	--	15	mV
Zero Crossing Threshold		PHASE − GND, DEM = 5V	−10	--	5	mV
Fault Protection
Current Limit (Positive)		GND − PHASE, RCS = 5kΩ	35	50	65	mV
		GND − PHASE, RCS = 20kΩ	170	200	230	mV
Output UV Threshold			60	70	80	%
OVP Threshold		With respect to error comparator	10	15	20	%
		threshold
OV Fault Delay		FB forced above OV threshold	--	20	--	μs
VDDP Under voltage Lockout		Rising edge, hysteresis = 20mV,	3.9	4.2	4.5	V
Threshold		PWM disabled below this level
Current Limit Step Time at Soft Start		Each step	--	128	--	clks
UV Blank Time		From S5 signal going high	--	512	--	clks
Thermal Shutdown		Hysteresis = 10°C	--	165	--	°C
Driver On-Resistance
UGATE Gate Driver (pull up)		(BOOT − PHASE) forced to 5V	--	2	4	Ω
UGATE Gate Driver (sink)		(BOOT − PHASE) forced to 5V	--	1	3	Ω
LGATE Gate Driver (pull up)		LGATE, High State (source)	--	2.5	6	Ω
LGATE Gate Driver (pull down)		LGATE, Low State (sink)	--	0.6	1.5	Ω
UGATE Gate Driver Source/Sink		UGATE forced to 2.5V,	--	1	--	A
Current		(BOOT − PHASE) forced to 5V
LGATE Gate Driver Source Current		LGATE Forced to 2.5V	--	1	--	A
LGATE Gate Driver Sink Current		LGATE Forced to 2.5V	--	3	--	A
Dead Time		LGATE Rising (PHASE = 1.5V)	--	40	--	ns
		UGATE Rising	--	40	--
Internal boost charging switch on		VDDP to BOOT, 10mA	--	--	80	Ω
resistance
					To be continued
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RT8207

Parameter	Symbol		Test Conditions					Min	Typ	Max	Unit
Logic I/O
Logic Input Low Voltage		S3, S5, DEM Low						--	--	0.8	V
Logic Input High Voltage		S3, S5, DEM High						2	--	--	V
Logic Input Current		S3/S5/DEM = VDD/GND						−1	0	1	μA
PGOOD (upper side threshold decide by OV threshold)
Trip Threshold (falling)		Measured at FB, with respect to						−13	−10	−7	%
		reference, no load. Hysteresis = 3%
Fault Propagation Delay		Falling edge, FB forced below						--	2.5	--	μs
		PGOOD trip threshold
Output Low Voltage		ISINK = 1mA						--	--	0.4	V
Leakage Current		High state, forced to 5.0V						--	--	1	μA
VTT LDO TA = 25°C, Unless Otherwise specification
		VDDQ = VLDOIN = 1.5V/1.8V,						−20	--	+20
		IVTT = 0A
VTT Output Tolerance	VVTTTOL	VDDQ = VLDOIN = 1.5V/1.8V,						−30	--	+30	mV
		IVTT = 1A
		VDDQ = VLDOIN = 1.5V/1.8V,						−40	--	+40
		IVTT = 2A,
			VDDQ			×0.95 ,
		VTT =	2					3	--	6
VTT Source Current Limit	IVTTOCLSRC										A
		PGOOD = High
		VTT = 0V						--	2	--
			VDDQ			×1.05
		VTT =	2					3	--	6
VTT Sink Current Limit	IVTTOCLSNK										A
		PGOOD = High
		VTT = VDDQ						--	2	--
		S5 = 5V, S3 = 0V,
VTT Leakage Current	IVTTLK		VDDQ					−10	--	10	μA
		VTT =	2
VTTFB Leakage Current	IVTTSNSLK	ISINK = 1mA						−1	--	1	μA
VTT Discharge Current	IDSCHRG	VDDQ = 0V, VTT = 0.5V,						10	30	--	mA
		S5 = S3 = 0V
					VDDQ
VTTREF Output Voltage	VVTTREF	VVTTREF =						--	0.9/0.75	--	V
					2
		VLDOIN = VDDQ = 1.5V,						−15	--	+15
VDDQ/2, VTTREF Output		IVTTREF < 10mA
	VVTTREFTOL										mV
Voltage Tolerance		VLDOIN = VDDQ = 1.8V,						−18	--	+18
		IVTTREF < 10mA
VTTREF Source Current	IVTTREFOCL	VVTTREF = 0V						10	40	80	mA
Limit

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