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TECHNICAL NOTE
High-performance Regulator IC Series for PCs
Switching Regulators for DDR-SDRAM Cores
BD9535MUV
Description BD9535MUV is a 2ch switching regulator controller with high output current which can achieve low output voltage (0.7V 2.0V) from a wide input voltage range (4.5V25V). High efficiency for the switching regulator can be realized by utilizing an 3 TM external N-MOSFET power transistor. A new technology called H Reg is a Rohm proprietary control method to realize TM ultra high transient response against load change. SLLM (Simple Light Load Mode) technology is also integrated to improve efficiency in light load mode, providing high efficiency over a wide load range. For the soft start/stop function, variable frequency function, short circuit protection function with timer latch, and tracking function are all built in. This 2ch switching regulator is specially designed for Chipset and Front Side Bus.
Features 3 TM 1) 2ch H REG Switching Regulator Controller 2) Light Load Mode and Continuous Mode Changeable 3) Thermal Shut Down (TSD), Under Voltage LockOut (UVLO), Over Current (detect the peak current) Protection (OCP), Over Voltage Protection (OVP), Short circuit protection with built-in timer-latch 4) Soft start function to minimize rush current during startup 5) Switching Frequency Variable (f=200KHz600kHz) 6) VQFN032V5050 package 7) Built-in Power good circuit 8) Adjustable to chip set spec by tracking function
Applications Laptop PC, Desktop PC, LCD-TV, Digital Components
Sep. 2008
Maximum Absolute Ratings (Ta=25) Parameter Input Voltage 1 Input Voltage 2 Input Voltage 3 BOOT Voltage BOOT-SW Voltage HG-SW Voltage LG Voltage Setting for Output Voltage Output voltage SS Voltage FS Voltage VREG voltage Current Limit setting Voltage Logic Input Voltage PGOOD Voltage CE Voltage Power dissipation Operating Temperature Range Storage Temperature Range Junction Temperature
*1 Not to exceed Pd.
Symbol VCC VDD VIN VBOOT1/2 VBOOT1-VSW1, VBOOT2-VSW2 VHG1-VSW1, VHG2-VSW2 VLG1/2 VREF1/2 VIs+1/2, VIs-1/2 VSS1/2 VFS VREG VILIM1/2 VEN1/2 VPGOOD1/2 VCE1/2 Pd Topr Tstg Tjmax
Rating 7 30 35 7
*1
Unit V V V V V V V V V V V V V V V V W
7 *1
*1 *1
7 *1
*1
VDD VCC VCC VCC VCC VCC VCC 7 7
*1
7 *1
*1
T.B.D -10+100 -55+150 +150
Operating Conditions (Ta=25) Parameter Input Voltage 1 Input Voltage 2 Input Voltage 3 BOOT Voltage SW Voltage BOOT-SW Voltage Logic Input Voltage Setting Voltage for Output Voltage Is Input Voltage MIN ON time
Symbol VCC VDD VIN VBOOT1/2 VSW1/2 VHG1-VSW1, VHG2-VSW2 VEN1/2 VREF1/2 VIs+1/2, VIs-1/2 tonmin
Min. 4.5 4.5 3.0 4.5 -2 4.5 0 0.7 0.7 -
Max. 5.5 5.5 28 30 33 5.5 5.5 2.0 2.0 100
Unit V V V V V V V V V nsec
This product should not be used in a radioactive environment.
2/18
ELECTRICAL CHARACTERISTICS (unless otherwise noted, Ta=25 VCC=5V,VDD=5V,VEN=3V,VIN=12V,VREF=1.8V,RFS=68k) Standard Value Parameter Symbol MIN. TYP. MAX.
[Whole Device] VCC bias current VIN bias current VCC standby current VIN standby current EN Low voltage 1,2 EN High voltage 1,2 (forced continuous mode) EN High voltage 1,2 (SLLM mode) EN bias current 1,2 VREG voltage [Under voltage lock out block] VCC threshold voltage VCC hysteresis voltage VIN threshold voltage VIN hysteresis voltage VREG threshold voltage VREG hysteresis voltage [Over Voltage Protection block] VOUT threshold voltage 1,2 [Power Good block] VOUT Power Good Low voltage 1,2 VOUT Power Good High voltage 1,2 Discharge ON resistance 1,2 Delay time 1,2 [H3REGTM Control block]
ON Time1 MAX ON Time 1 MIN OFF Time 1
Unit
mA A A A V V V A V V mV V mV V mV V
Conditions
Icc IIN Istb IIN_Stb VEN_low1,2 VENth_con1,2 VENth_sllm1,2 IEN1,2 VREG1,2 Vcc_UVLO dVcc_UVLO VIN_UVLO dVIN_UVLO VREG_UVLO dVREG_UVLO VOUT_OVP1,2
GND 2.3 4.2 2.475 4.1 100 2.4 100 2.0 100
1.4 200 20 7 2.500 4.3 160 2.6 160 2.2 160
2.0 400 20 40 0.8 3.8 5.5 10 2.525 4.5 220 2.8 220 2.4 220
VEN1=VEN2=0V VEN1=VEN2=0V
IREG=500A Ta=-10100*2 VCC:Sweep up VCC:Sweep down VIN:Sweep up VIN:Sweep down VREG:Sweep up VREG:Sweep down
VREFx1.15 VREFx1.20 VREFx1.25
VPGOOD_low1,2 VREFx0.87 VREFx0.90 VREFx0.93 V VREFx VREFx VREFx VPGOOD_high1,2 V 1.07 1.10 1.13 Ron_PGOOD1,2 1.0 2.0 k TPGOOD1,2 150 250 350 sec
ton1 Tonmax1 Toffmin1
ton2
ON Time 2
MAX ON Time 2 MIN OFF Time 2
Tonmax2 Toffmin2
RHGhon1,2 RHGlon1,2 RLGhon1,2 RLGlon1,2 ISS_char1,2 ISS_dis1,2 VSS_disth1,2 VSS_STB1,2 VIlim11,2 VIlim21,2 VReIlim11,2 VReIlim21,2 VIS_off1,2 IREF1,2 IIs+1,2 IIs-1,2 Vthscp1,2 tscp1,2
400 2.5 500 250 2.5 500
500 3.0 600 350 3.0 600
600 3.5 700 450 3.5 700
nsec sec nsec
RFS=68k
nsec
sec nsec
RFS=68k
[FET Driver block] HG upper side ON resistance 1,2 HG lower side ON resistance 1,2 LG upper side ON resistance 1,2 LG lower side ON resistance 1,2 [Soft Start block] Charge current Discharge current Discharge threshold voltage Standby voltage [Current Limit block] Current limit threshold voltage 1_1,2 Current limit threshold voltage 2_1,2 Reflux current limit threshold voltage1_1,2 Reflux current limit threshold voltage2_1,2 [Output Voltage Sense block] VIs offset voltage1,2 REF bias current1,2 Is+ input current1,2 Is- input current1,2 [SCP block] Threshold voltage 1,2 Delay time 1,2
*2
1.5 1.5 40 170 -60 -230 VREF -3m -100 -100 -100 0.7
3.0 2.0 2.0 0.5 2 2 0.1 50 200 -50 -200 VREF 0 0 0 VREFx0.7 1
6.0 4.0 4.0 1.0 2.5 2.5 0.2 50 60 230 -40 -170 VREF +3m 100 100 100 1.3
A A V mV mV mV mV mV V nA nA nA V msec VILIM=0.5V VILIM =2.0V VILIM =0.5V VILIM =2.0V Ta=-10100*2 VIs+=1.8V VIs-=1.8V
Designed guarantee
3/18
Block Diagram
VCC
VIN
VREG
SS1
EN1
Reference Block SLLM1 REFx0.7 SSx0.7 Is-1
VREF VIN
UVLO 2.5V 2.5VReg EN1 EN2 SCP H Reg Controller Block
3
SS
BOOT1
Soft Start /Stop Block
BEN
HG1 SW1
Driver Circuit
Delay FS
R S
Q
SLLM SLLM1 Current Limit + -
VDD LG1
OVP1
REF1
SS IS-1 Thermal Protection TSD + + -
PGND1 CE1 Is-1 Is+1 ILIM1
UVLO ILIM SCP TSD
ILIM
VCC
PGOOD1
Is-1 Is-2 VREF VIN UVLO POWER GOOD OVP2 OVP1
PGOOD2 SS2
EN2
Reference Block SLLM2
SS VIN BEN Soft Start /Stop Block
BOOT2 HG2
REFx0.7 SSx0.7 Is-2
Delay
SCP H Reg Controller Block + + 3
R S
Q
SLLM SLLM2 Current Limit + -
REF2
SS IS-2
Driver Circuit VDD
SW2
ILIM
LG2 PGND2
OVP2
UVLO ILIM SCP TSD
CE2 FS ILIM2 IS+2 IS-2
GND
Pin Configuration
Pin Function Table
PIN No. 1 2 3
REF2 ILIM2 EN2 SS2
PGOOD2
BOOT2
PIN name BOOT1 CE1 PGOOD1 EN1 SS1 ILIM1 REF1 VREG FS Is-1 Is+1 GND VCC Is+2 Is-2 VIN REF2 ILIM2 SS2 EN2 PGOOD2 CE2 BOOT2 HG2 SW2 PGND2 LG2 VDD LG1 PGND1 SW1 HG1 FIN
HG2
CE2
4 5
16 VIN 15 Is-2 14 Is+2 13 VCC 12 GND 11 Is+1 10 Is-1 9 FS
24 SW2 25 PGND2 26 LG2 27 VDD 28 LG1 29 PGND1 30 SW1 31 HG1 32 1 BOOT1
23
22
21
20
19
18
17
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 reverse
2 CE1
3 PGOOD1
4 EN1
5 SS1
6 ILIM1
7 REF1
8 VREG
PIN function HG driver power supply pin 1 Reactive pin 1 for lower ESR output capacitor Power good signal output pin 1 Enable input pin 1 (00.8V:OFF, TM 2.33.8V:continuous mode, 4.25.5V:SLLM ) Connective pin 1 of capacitor for soft start/soft stop Current limitsetting pin 1 Output voltage setting pin 1 Reference voltage inside IC (Output : 2.5V) Resistance connective pin for setting frequency Current sense pin- 1 Current sense pin+ 1 Sense GND Power supply input pin Current sense pin+ 2 Current sense pin- 2 Battery voltage sense pin Output voltage setting pin 2 Current limit setting pin 2 Connective pin 2 of capacitor for soft start/soft stop Enable input pin 2 (00.8V:OFF, TM 2.33.8V:continuous mode, 4.25.5V:SLLM ) Power good signal input pin 2 Reactive pin 2 for lower ESR output capacitor HG driver power supply pin 2 High side FET gate drive pin 2 High side FET source pin 2 Power GND2 Low side FET gate drive pin 2 Power supply input pin Low side FET gate drive pin 1 Power GND 1 High side FET source pin 1 High side FET gate drive pin 1 substrate
4/18
Reference Data
100
100 90
80 Efficiency[%]
Efficiency[%]
80 70 60 50 40 30 20 10
VO
100[mV/div]
60
40
20
VIN=7V VIN =12V VIN =19V
VIN=7V VIN =12V VIN =19V
HG LG
0 0.01 0.1 1 Load Current[A] 10
IO
5[A/div]
0.1 1 Load Current[A] 10
0.01
Fig.1 Io-efficiency SLLM
Fig.2 Io- efficiency Continuous mode
Fig.3 Transitional response (Io=05A) Continuous mode
VO
100[mV/div]
VO
100[mV/div]
VO
100[mV/div]
HG LG
HG LG
HG LG
5[A/div]
IO
IO
5[A/div]
IO
5[A/div]
Fig.4
Transitional response (Io=50A) Continuous mode
Fig.5
Transitional response (Io=05A) SLLM
Fig.6
Transitional response (Io=50A) SLLM
VO
VO
VO
HG SW LG
HG SW LG
HG SW LG
Fig.7 SLLMIo=0A
Fig.8 SLLMIo=0.4A
Fig.9 SLLMIo=1A
500
400 Frequency [kHz]
EN
EN
300 Continuous mode
PGOOD
SLLM
PGOOD
200
100
VIN=7V VIN =12V VIN =19V
VIN=7V VIN =12V VIN =19V
0.1 1 Load Current[A] 10
0 0.01
SS VO
SS VO
Fig.10 Io-Frequency
Fig.11 starting wave
Fig.12 stopping wave
5/18
Evaluation Board Circuit
VCC 5V U1 VCC BD9535MUV VQFN032V5050 VDD C2 HG1 VREG VREG EN1 C4 EN1 C5 ILIM1 REF1 R14 R11 TRACK1 C7 R12 VCC EN2 VREG SW2 5V R19 R16 R18 R17 ILIM2 R20 R21 R23 1.2V R24 C11 R25 R58 TRACK2 SS2 R26 C12 REF2 C10 EN1 C9 C8 SS1 BOOT2 HG2 SW2 LG2 LG2 PGND2 Is+2 Is-2 PGOOD2 FS GND FS R57 C31 R62 R46 M2 D4 R51 R61 R52 VCC R54 PGOOD2 C28 C29 C30 R44 R45 D2 HG2 SW2 PGND1 Is+1 Is-1 PGOOD1 VDD C23 VIN C21 R60 VIN VREG(2.5V) SW1 LG1 LG1 R33 M1 D3 R59 R38 R39 VCC R41 PGOOD1 C18 C19 C20 BOOT1 R31 R32 VDD D1 GND C13 PGND GND PGND1 PGND2
R1
VDD
VDD
C1
VIN
VREG R4 0.5V R5 C6 VREG R10 1.8V R6 12V
VIN
R2
HG1 SW1
C14
M1
C15 L1
C16 R37 1.8V/5A
R3 C3 VCC SW1 5V R8 R7
R9
C24
M2
C25 L2
C26 R50 1.2V/5A
0.5V
VREG
Evaluation Board Parts List
Designation R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R14 R16 R17 R18 R19 R20 R21 R23 R24 R25 R26 R31 R32 R33 R37 R38 R39 R41 R44 R45 R46 R50 R51 R52 Value 10 0 1k 200k 51k 0 51k 91k 0 22k 56k 0 10k 51k 91k 0 200k 51k 0 39k 36k 0 10k 0 0 0 7m 0 0 100k 0 0 0 7m 0 0 Part No. MCR03EZPF10R0 MCR03EZHJ000 MCR03EZPF1001 MCR03EZPF2003 MCR03EZPF5102 MCR03EZHJ000 MCR03EZPF5102 MCR03EZPF9102 MCR03EZHJ000 MCR03EZPF2202 MCR03EZPF5602 MCR03EZHJ000 MCR03EZPF1002 MCR03EZPF5102 MCR03EZPF9102 MCR03EZHJ000 MCR03EZPF2003 MCR03EZPF5102 MCR03EZHJ000 MCR03EZPF3902 MCR03EZPF3602 MCR03EZHJ000 MCR03EZPF1002 MCR03EZHJ000 MCR03EZHJ000 MCR03EZHJ000 PMR100HZPFU7L00 MCR03EZHJ000 MCR03EZHJ000 MCR03EZPF1003 MCR03EZHJ000 MCR03EZHJ000 MCR03EZHJ000 PMR100HZPFU7L00 MCR03EZHJ000 MCR03EZHJ000 Company ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM Designation R54 R57 R58 R59 R60 R61 R62 C1 C2 C3 C4 C6 C7 C8 C10 C11 C12 C13 C14 C15 C18 C21 C23 C24 C26 C28 C31 D1 D2 D3 D4 L1 L2 M1 M2 U1 Value 100k 75k 0 100 100 100 100 10uF 10uF 0.01uF 1uF 0.1uF 0.1uF 0.047uF 0.1uF 0.1uF 0.047uF 10uF 0.1uF 10uF(25V) 200uF 100pF 10uF 0.1uF 10uF(25V) 200uF 100pF 2.5uH 2.5uH Part No. MCR03EZPF1003 MCR03EZPF7502 MCR03EZHJ000 MCR03EZPF1000 MCR03EZPF1000 MCR03EZPF1000 MCR03EZPF1000 CM21B106M06A CM21B106M06A MCH185CN103KB CM105B105K06A MCH185CN104K MCH185CN104K MCH185CN473K MCH185CN104K MCH185CN104K MCH185CN473K CM21B106M06A MCH185CN104K CT32X5R106K25A 2R5TPE220MF MCH185A101J CM21B106M06A MCH185CN104K CT32X5R106K25A 2R5TPE220MF MCH185A101J PB521S-30 PB521S-30 RSX501L-20 RSX501L-20 CDEP105-2R5MC-32 CDEP105-2R5MC-32 SP8K4(2in1) SP8K4(2in1) BD9535MUV Company ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM ROHM KYOCERA SANYO ROHM ROHM ROHM KYOCERA SANYO ROHM ROHM ROHM ROHM ROHM Sumida Sumida ROHM ROHM ROHM
6/18
Pin Descriptions VCC (13pin) This is the power supply pin for IC internal circuits, except the FET driver. The maximum circuit current is 2.0mA. The input supply voltage range is 4.5V to 5.5V. It is recommended that a 0.1uF bypass capacitor be put in this pin. EN1/EN2 (4pin/20pin) When EN pin voltage is at least 2.3V, the status of this switching regulator become active. Conversely, the status switches off when EN pin voltage goes lower than 0.8V and circuit current becomes 20uA or less. This pin is also switch pin of SLLMTM. The voltage is 2.3V to 3.8V : forced continuous mode, 4.2V to 5.5V : SLLMTM. These operating modes are changeable to control by power supply system 3.3V or 5V. VDD (28pin) This is the power supply pin to drive the LOW side FET. It is recommended that a 1uF bypass capacitor be established to compensate for rush current during the FET ON/OFF transition. VREG (8pin) This is the reference voltage output pin. The voltage is 2.5V, with 100uA current ability. It is recommended that a 1uF capacitor be established between VREF and GND. It is available to set VREF by the resistance division value from VREG in case VREF is not set from an external power supply. REF1/REF2 (7pin/17pin) This is the setting pin for output voltage of switching regulator. It is so convenient to be synchronized to outside power supply. This IC controls the voltage in the status of VREF1Vis-1 or VREF2Vis-2. ILIM1/ILIM2 (6pin/18pin) BD9535MUV detects the voltage between Is+ pin and Is- pin and limits the output current (OCP). Voltage equivalent to 1/10 of the ILIM voltage is the voltage drop of external current sense resistor. A very low current sense resistor or inductor DCR can also be used for this platform. SS1/SS2 (5pin/19pin) This is the adjustment pin to set the soft start/stop time. SS voltage is low during standby status. When EN is ON, the soft start time can be determined by the SS charge current and capacitor between SS-GND. Until SS reaches REF voltage, the output voltage is equivalent to SS voltage. VIN (16pin) The duty cycle is determined by input voltage and controls output voltage. In other words, the output voltage is affected by input voltage. Therefore, when VIN voltage fluctuates, the output voltage becomes also unstable. Since the VIN line is also the input voltage of the switching regulator, stability depends on the impedance of the voltage supply. It is recommended to establish a bypass capacitor or CR filter suitable for the actual application. FS (9pin) This is the pin to adjust the switching frequency with the resistor. The frequency range is from 200kHz to 600kHz. Is+1/Is+2,Is-1/Is-2 (11pin/14pin/10pin/15pin) These pins are connected to both sides of the current sense resistor to detect output current. The voltage drop between Is+ and Is- is compared with the voltage equivalent to 1/10 of ILIM voltage. When this voltage drop hits the specified voltage level, the output voltage is OFF. BOOT1/BOOT2 (1pin/23pin) This is the voltage supply to drive the high side FET. The maximum absolute ratings are 35V (from GND) and 7V (from SW). BOOT voltage swings between (VIN+Vcc) and Vcc during active operation. HG1/HG2 (29pin/27pin) This is the voltage supply to drive the Gate of the high side FET. This voltage swings between BOOT and SW. High-speed Gate driving for the high side FET is achieved due to the low on-resistance (3 ohm when HG is high, 2 ohm when HG is low) driver. SW1/SW2 (31pin/25pin) This is the source pin for the high side FET. The maximum absolute ratings are 30V (from GND). SW voltage swings between VIN and GND. LG1/LG2 (29pin/27pin) This is the voltage supply to drive the Gate of the low side FET. This voltage swings between VDD and PGND. High-speed Gate driving for the low side FET is achieved due to the low on-resistance (3 ohm when LG is high, 0.5 ohm when LG is low) driver. PGND1/PGND2 (30pin/26pin) This is the power ground pin connected to the source of the low side FET. This is the source pin for low-side FET. It is prepared for each channel to reduce the interference among channels. PGOOD1/PGOOD2 (3pin/21pin) This is the monitor pin for output voltage (Is-1/Is-2). When the output voltage is within 10% of setting voltage (REF1/2), High is output. It is open drain pin and connects to other power supply through the pull-up resistance. CE1/PCE2 (2pin/22pin) This pin is helpful for using ceramic capacitor as output capacitor. It is stable to use low ESR capacitor (small ripple voltage). GND (12pin) This is GND pin for Analog and Digital series. Set the reverse side of IC equivalent to the voltage of this pin. 7/18
Explanation of Operation The BD9535MUV is a 2ch synchronous buck regulator controller incorporating ROHM's proprietary H3REG CONTROLLA control system. When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the TON time interval. Thus, it serves to improve the regulator's transient response. Activating the Light Load Mode will also exercise Simple Light Load Mode (SLLM) control when the load is light, to further increase efficiency.
3 TM H Reg control (Normal operation)
Is-(VOUT) REF
When VOUT falls to a threshold voltage (REF), the drop is detected, activating the H3REG CONTROLLA system. REF 1 x VIN f
tON= HG
[sec](1)
HG output is determined by the formula above. LG
(VOUT drops due to a rapid load change) Is-(VOUT) REF When VOUT drops due to a rapid load change, and the voltage remains below REF after the programmed tON time interval has elapsed, the system quickly restores VOUT by extending the tON time, improving the transient response.
Io HG LG
tON+
Is-(VOUT) REF
HG LG
In SLLM (SLLM=0V), SLLM function is operated when LG pin is OFF and the coil current is lower than 0A (the current goes from VOUT to SW). And it stops to output next HG. When VOUT goes lower than REF voltage again, the status of HG is ON.
0A VIN
VIN REF H3RegTM
CONTROLLA R S Q
SLLMTM
Driver Circuit
VOUT
Is-(VOUT) VCC EN 4V EN 02.3V 2.33.8V 4.25.5V 8/18 Output OFF ON ON Operating mode Forced continuous mode SLLMTM
Timing Chart * Soft Start Function
EN TSS(ON) SS
Soft start is exercised with the EN pin set high. Current control takes effect at startup, enabling a moderate output voltage "ramping start." Soft start timing and incoming current are calculated with formulas (2) and (3) below. Soft start time
VOUT
TSS(ON)= REFxCss [sec] (2) 2A(typ) rush current
IIN IIN=
CoxVOUT Tss
[A] (3)
(Css: Soft start capacitor; Co: Output capacitor)
* Soft Stop Function Soft stop is exercised with the EN pin set low. Current control takes effect at startup, enabling a moderate output voltage. Soft start timing and incoming current are calculated with formulas (4) below. 0.1V Soft stop time Is(VOUT)
Spontaneous discharge (It is determined by load and output capacitor.)
EN TSS(OFF) 2VBE SS
TSS(OFF)=
(REF+2VBE-0.1)xCss 2A(typ)
[sec] (4)
Tdelay VBE = 0.6[V] (typ) Tdelay =
2VBExCSS 2A(typ)
[sec] (5)
Synchronous operation with other power supply 3.3V(other power supply) These power supply sequences are realized to connect SS pin to other power supply output through the resistance (10k).
1.8V (BD9535 output 1) 1.2V (BD9535 output 2)
9/18
Timing chart Over current protection circuit
tON HG
tON
tMAX
tON
LG ILIMIT IL
During the normal operation, when VOUT becomes less than REF Voltage, HG becomes High during the time TON. However, when inductor current exceeds ILIMIT threshold, HG becomes OFF. After MAX ON TIME, HG becomes ON again if the output voltage is lower than the specific voltage level and IL is lower than ILIMIT level.
Timer Latch Type Short Circuit Protection Is(VOUT) REFx0.7
Spontaneous discharge
1msec
When output voltage (Is-) falls to REFx0.7 or less, SCP comparator inside IC is exercised. If the status of High is continued 1ms or more (programmed time inside IC), the IC goes OFF. It can be restored either by reconnecting the EN pin or disabling UVLO.
SCP
EN /UVLO
Output Over Voltage Protection
Is(VOUT)
REFx1.2
160mV
When output rise to or above REFx1.2, output over voltage protection is exercised, and low side FET goes up maximum for reducing output. LG=High, HG=Low. When output falls, it returns to the standard mode.
HG
LG
Switching
10/18
External Component Selection 1. Inductor (L) selection The inductor value is a major influence on the output ripple current. As formula (5) below indicates, the greater the inductor or the switching frequency, the lower the ripple current. (VIN-VOUT)xVOUT IL= [A](6) LxVINxf The proper output ripple current setting is about 30% of maximum output current. IL=0.3xIOUTmax. [A](7) L= (VIN-VOUT)xVOUT LxVINxf [H](8)
IL
VIN
IL VOUT L Co
(IL: output ripple current; f: switch frequency) Output ripple current Passing a current larger than the inductor's rated current will cause magnetic saturation in the inductor and decrease system efficiency. In selecting the inductor, be sure to allow enough margin to assure that peak current does not exceed the inductor rated current value. To minimize possible inductor damage and maximize efficiency, choose a inductor with a low (DCR, ACR) resistance. 2.Output Capacitor (CO) Selection
VIN
When determining the proper output capacitor, be sure to factor in the equivalent series resistance required to smooth out ripple volume and maintain a stable output voltage range. Output ripple voltage is determined as in formula (9) below.
VOUT
L
VOUT=ILxESR+ESLxIL/TON(9) (IL: Output ripple current; ESR: CO equivalent series resistance, ESL: CO equivalent series inductance) In selecting a capacitor, make sure the capacitor rating allows sufficient margin relative to output voltage. Note that a lower ESR can minimize output ripple voltage.
ESR ESL Co
Output capacitor
Please give due consideration to the conditions in formula (10) below for output capacity, bear in mind that output rise time must be established within the soft start time frame. Co TSSx(Limit-IOUT) VOUT (10) Tss: Soft start time Limit: Over current detection IOUT: Output current
Note: Improper capacitor may cause startup malfunctions. 3. Input Capacitor (Cin) Selection
VIN Cin
The input capacitor selected must have low enough ESR resistance to fully support large ripple output, in order to prevent extreme over current. The formula for ripple current IRMS is given in (11) below.
VOUT
L
Co
IRMS=IOUTx
VOUT (VIN-VOUT) VIN IOUT 2
[A](11)
Where VIN=2xVOUT, IRMS= Input Capacitor
A low ESR capacitor is recommended to reduce ESR loss and maximize efficiency.
11/18
4. MOSFET Selection Loss on the main MOSFET
VIN main switch
Pmain=PRON+PGATE+PTRAN = VOUT VIN xRONxIOUT2+QgxfxVDD+
2 VIN xCrssxIOUTxf
VOUT L Co
IDRIVE
(12)
(Ron: On-resistance of FET; Qg: GATE total charge f: Switching frequency, Crss: FET inverse transfer function; IDRIVE: Gate peak current) Loss on the synchronous MOSFET Psyn=PRON+PGATE = VIN-VOUT VIN xRONxIOUT2+ QgxfxVDD (13)
synchronous switch
5. Setting Detection Resistance VIN
L IL
R Co
The over current protection function detects the output ripple current peak value. This parameter (setting value) is determined as in formula (14) below. VOUT ILMIT= VILIMx0.1 R [A](14)
(VILIM: ILIM voltage; R: Detection resistance)
Is+ Is+ Current limit
VIN IL L RL VOUT Co
When the over current protection is detected by DCR of coil L, this parameter (setting value) is determined as in formula (14) below. ILMIT=VILIMx0.1x (RL= L rxC ) RL: the DCR value of coil) rxC L [A](15)
r
C
(VILIM:ILIM voltage
Is+ Is+ Current limit
IL ILIMIT
detect point
As soon as the voltage drop between Is+ and Is- generated by the inductor current becomes specific threshold, the gate voltage of the high side MOSFET becomes low. Since the peak voltage of the inductor ripple current is detected, this operation can sense high current ripple operation caused by inductance saturated rated current and lead to high reliable systems. t
0
12/18
6. Setting frequency 1ch The On Time (TON) at steady state is determined by resistance value connected to FS pin. But actually SW rising time and falling time come up due to influence of the external MOSFET gate capacity or switching speed and TON is increased. The frequency is determined by the following formula after TON, input current and the REF voltage are fixed. REF VINxTON
700 600 Frequency [kHz] 500 400 300
VIN=3V 5V 7V 12V 19V
F=
200 100 0 0 50 100
RFS[k]
VREF=1.8V
(15)
150
200
Consequently, total frequency becomes lower than the formula above. TON is also influenced by Dead Time around the output current 0A area in continuous mode. This frequency becomes lower than setting frequency. It is recommended to check the steady frequency in large current area (at the point where the coil current doesn't back up).
2ch
900 800 700 Frequency [kHz] 600 500 400 300 200 100
VREF=1.8V VIN=3V 5V 7V 12V 19V
0 0 50 100
RFS[k]
150
200
13/18
7. Setting standard voltage (REF) VIN REF H Reg
3 TM
R S
Q
It is available to synchronize setting the reference voltage (REF) with outside supply voltage [V] by using outside power supply voltage.
CONTROLLA
Outside voltage
VOUT VREG R1 REF VIN H3RegTM CONTROLLA R2 R S Q
It is available to set the reference voltage (REF) by the resistance division value from VREG in case it is not set REF from an external power supply. R2 R1+R2
REF=
xVREG [V](17)
VOUT 8. Setting output voltage This IC is operated that output voltage is REFIs-(VOUT). And it is operated that output voltage is feed back to FB pin in case the output voltage is 0.7V to 2.0V. Actually, the average value of ripple voltage is added to output voltage. Output voltage = VIN REF H3RegTM CONTROLLA Is-(VOUT) R S SLLM Q REF + 1 2 xILxESR(18) VIN SLLMTM
Output voltage
Driver Circuit
ESR
In case the output voltage range is 0.7V to 2.0V. It is operated that the resistance division value of the output voltage is feed back to Is-pin in case the output voltage is more than 2.0V. output voltage = R1+R2 R2 x REF + 1 2 xILxESR(19)
In this time, the frequency is also amplified by power of the resistance division. It is determined as in formula (20) below. Frequency= VIN H3RegTM REF CONTROLLA R S SLLM Is-(VOUT) Q SLLM
TM
R1+R2 R2
x(frequency determined by REF) [Hz](20) VIN
Output
Driver Circuit R1
ESR
In case the output voltage range is more than 2.0V. 14/18
R2
I/O Equivalent Circuit 1pin, 23pin (BOOT1/2) 2pin, 22pin (CE1/2) 3pin, 21pin (PGOOD1/2)
300 HG SW
4pin, 20pin (EN1/2)
5pin, 19pin (SS1/2)
6pin, 18pin (ILIM1/2)
430K
7pin, 17pin (REF1/2)
8pin (VREG)
9pin (FS)
1.2M
400K
10pin, 15pin (Is-1/2)
11pin, 14pin (Is+1/2)
16pin (VIN)
24pin, 32pin (HG1/2)
BOOT BOOT
25pin, 31pin (SW1/2)
BOOT HG 300K
27pin, 29pin (LG1/2)
VDD
100K 300K 300K SW 300K
15/18
Operation Notes 1. Absolute maximum ratings An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down the devices, thus making impossible to identify breaking mode, such as a short circuit or an open circuit. If any over rated values will expect to exceed the absolute maximum ratings, consider adding circuit protection devices, such as fuses.
2. Connecting the power supply connector backward Connecting of the power supply in reverse polarity can damage IC. Take precautions when connecting the power supply lines. An external direction diode can be added. 3. Power supply lines Design PCB layout pattern to provide low impedance GND and supply lines. To obtain a low noise ground and supply line, separate the ground section and supply lines of the digital and analog blocks. Furthermore, for all power supply terminals to ICs, connect a capacitor between the power supply and the GND terminal. When applying electrolytic capacitors in the circuit, not that capacitance characteristic values are reduced at low temperatures. 4. GND voltage The potential of GND pin must be minimum potential in all operating conditions. 5. Thermal design Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions. 6. Inter-pin shorts and mounting errors Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any connection error or if pins are shorted together. 7. Actions in strong electromagnetic field Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to malfunction. 8. ASO When using the IC, set the output transistor so that it does not exceed absolute maximum ratings or ASO. 9. Thermal shutdown circuit The IC incorporates a built-in thermal shutdown circuit (TSD circuit). The thermal shutdown circuit (TSD circuit) is designed only to shut the IC off to prevent thermal runaway. It is not designed to protect the IC or guarantee its operation. Do not continue to use the IC after operating this circuit or use the IC in an environment where the operation of this circuit is assumed. TSD on temperature [C] (typ.) Hysteresis temperature [C] (typ.) BD9535MUV 175 15 10. Testing on application boards When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress. Always discharge capacitors after each process or step. Always turn the IC's power supply off before connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as an antistatic measure. Use similar precaution when transporting or storing the IC.
16/18
11. Regarding input pin of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersection of these P layers with the N layers of other elements, creating a parasitic diode or transistor. For example, the relation between each potential is as follows: When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Parasitic diodes can occur inevitable in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Accordingly, methods by which parasitic diodes operate, such as applying a voltage that is lower than the GND (P substrate) voltage to an input pin, should not be used.
Resistor Pin A Pin A
P
+
Transistor (NPN) Pin B
C B E B P P
+
Pin B
N P P
+
N
N
Parasitic element
N
P+
N N
C E
P substrate Parasitic element
GND
P substrate Parasitic element
GND GND GND
Parasitic element
Other adjacent elements
Fig. 13 Example of IC structure 12. Ground Wiring Pattern When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns, placing a single ground point at the ground potential of application so that the pattern wiring resistance and voltage variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the GND wiring pattern of any external components, either.
Power Dissipation
[mW] 1000 980mW
800
mounted on glass epoxy PCB 70x70mmx1.6mm j-a=127.0/W
Power Dissipation (Pd)
600
IC unit time j-a=403.2/W
400 310mW
200
0
25
50
75
100
125
150
[]
Ambient temperature (Ta)
17/18
Type Designations (Selections) for Ordering
B
D
9
5
3
5
M
U
V
E
2
Product name
BD9535
Package type
MUV = VQFN032V5050
Taping type name E2= Embossed carrier tape
VQFN032V5050

Tape Quantity Direction of feed
Embossed carrier tape(with dry pack) 2500pcs E2
(The direction is the 1pin of product is at the upper left when you hold reel on the left hand and you pull out the tape on the right hand)
1234
1234
(Unit:mm)
Reel
1pin
When you order , please order in times the amount of package quantity.
1234
1234
Direction of feed
1234
Catalog No.08T453A '08.9 ROHM (c)
1234
Appendix
Notes
No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM CO.,LTD. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). If you wish to use any such Product, please be sure to refer to the specifications, which can be obtained from ROHM upon request. Examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. Great care was taken in ensuring the accuracy of the information specified in this document. However, should you incur any damage arising from any inaccuracy or misprint of such information, ROHM shall bear no responsibility for such damage. The technical information specified herein is intended only to show the typical functions of and examples of application circuits for the Products. ROHM does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by ROHM and other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. The Products specified in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, office-automation equipment, communication devices, electronic appliances and amusement devices). The Products are not designed to be radiation tolerant. While ROHM always makes efforts to enhance the quality and reliability of its Products, a Product may fail or malfunction for a variety of reasons. Please be sure to implement in your equipment using the Products safety measures to guard against the possibility of physical injury, fire or any other damage caused in the event of the failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM shall bear no responsibility whatsoever for your use of any Product outside of the prescribed scope or not in accordance with the instruction manual. The Products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-controller or other safety device). ROHM shall bear no responsibility in any way for use of any of the Products for the above special purposes. If a Product is intended to be used for any such special purpose, please contact a ROHM sales representative before purchasing. If you intend to export or ship overseas any Product or technology specified herein that may be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to obtain a license or permit under the Law.
Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact your nearest sales office.
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Copyright (c) 2008 ROHM CO.,LTD.
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Appendix1-Rev3.0

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