【经验】圣邦微3A大电流LDO SGM2208无法实现低压差输出原因分析与解决

时间： 2021-04-01 来源：世强

技术问答

某客户在电路设计时采用BUCK芯片+LDO为后级板卡供电，电压转换为DC28V→DC6V→DC5.5V，实际负载电流在600mA左右，所以后级选择了圣邦微3A大电流LDO SGM2208，目的是为了保证输出电压纹波指标，另外考虑到LDO热问题，选择DC6V转5.5V，利用SGM2208低压差（见图1）减少芯片发热，但实际测试中却无法正常输出。

图1：SGM2208压差参数

问题分析：

在电路设计时，该客户是直接将Ctrl脚和Vin脚连在一起，此时Vctrl供电为6V，而Vout脚是设置为5V，参考SGM2208数据手册，发现Vctrl对Vout最小供电为2.7V（Vctrl供电参数见图2），即要保证Vctrl=Vout+2.7V，显然6-5=1＜2.7V，不能满足。

图2：SGM2208 Vctrl供电参数

两种解决办法：

1、可采用典型应用电路（见图3）设计，将Vin和Vctrl单独供电，将Ctrl脚连在前级DCDC输入DC28V端，规格书要求Ctrl to Vout最大耐压28 V，此时Vout 为5V，Ctrl实际电压在23V，符合SGM2208的Ctrl脚供电范围；

2、提高前级DCDC输出至9V，Vin和Vctrl一起连在9V，9-5.5=3.5＞2.7，满足SGM2208的Ctrl脚供电范围。

图3：SGM2208典型应用电路

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SGMICRO（圣邦微）信号链和电源管理芯片选型指南

描述- SGMICRO specializes in high-performance and high-quality analog and mixed-signal integrated circuits, and is committed to building a comprehensive portfolio of the highest quality analog and mixed-signal integrated circuits to address all customer needs.

型号- SGM11108M,SGM8306-2,SGM8306-1,SGM61450,SGM3733B,SGM11108E,SGM852,SGM853,SGM851,SGM5347-12,SGM2558A,SGM2558B,SGM8261-5,SGM2564,SGM8261-1,SGM5347-10,SGM8261-2,SGM2549,SGM48017C,SGM72110,SGM8094,SGM836,SGM8091,SGM837,SGM61220,SGM8092,SGM8093,SGM835,SGM72108,SGM2553,SGM72106,SGM2555,SGM809B,SGM4519,SGM4517,SGM4518,SGM48010,SGM11106C,SGM63600,SGM41611,SGM4520,SGM4521,SGM48005,SGM8417-4,SGM8417-2,SGM4051C,SGM48000,SGM48001,SGM48002,SGM3843A,SGM61433,SGM621,SGM84782,74HC574,SGM58031,SGM620,SGM862,SGM41600,SGM2572,SGM41603,SGM860,SGM2571,SGM51622H,SGM4995,SGM4511,SGM2574,SGM4996,SGM4512,SGM4510,SGM2575,SGM51622D,SGM4515,SGM8T245S,SGM4516,SGM8250-1,SGM8250-2,SGM4514,SGM3209,SGM809,SGM8557-3,SGM8557-1,SGM8557-2,SGM803,SGM61012,SGM804,SGM802,SGM61013,SGM810,SGM811,SGM61007,SGM61006,SGM4782,SGM7237B,SGM8902,SGM8903,SGM8904,SGM4542,SGM8905,SGM4548,SGM4549,SGM3699,SGM4546,SGM4547,SGM48013C,SGM62110,SGM61020,SGM62112,AAP6153A,SGM61022,SGM62111,SGM800,SGM2596,SGM3200,SGM3206,SGM8270-2,SGM3207,SGM4535,SGM3204,SGM8270-4,SGM8T245,SGM829,SGM61230,SGM42512,SGM41664,SGM825,SGM61232,SGM823,SGM61234,SGM824,SGM891B,SGM42507,SGM42506,SGM40567,SGM4560,SGM42505,SGM4561,SGM6503,SGM4566,SGM8925,SGM6502,SGM8926,SGM6501,SGM4564,SGM8927,SGM5349-16,SGM4565,SGM6505,SGM4568,SGM6504,SGM8909,SGM818,SGM890B,SGM816,SGM42501,SGM40565,SGM42500,SGM814,SGM815,SGM812,SGM40560,SGM40561,SGM821,SGM822,SGM61235,SGM820,SGM4551,SGM4552,SGM4550,SGM4555,SGM4556,SGM4553,SGM4554,SGM51652S8,SGM8910,SGM5347-8,SGM4558,SGM11124E,SGM37863A,SGM11124F,74LVC2T45,SGM893B,SGM4581,SGM8941,SGM4582,SGM4583,SGM48521Q,SGM8704,SGM4588,SGMNQ59430,SGM8705,SGM4589,SGM8706,SGM8707,SGM8942,SGM8701,SGM8702,SGM8703,SGM12213A,SGM11210A,SGM61060,SGM2050C,SGM12UB1D2,SGM892B,SGM8276-4,SGM6510,SGM4573,SGM3001,SGM4574,SGM42513,SGM6514,SGM3005,SGM6513,SGM4578,SGM8276-2,SGM3002,SGM6512,SGM42622B,SGM8276-1,SGM3003,SGM6511,SGM4576,SGM8931,SGMOP17C,SGM8932,SGM8933,SGM6516,SGM12214A,SGM8934,SGM6515,SGM11210M,SGMNE20220,74AVC8T245,SGM3141B,SGM61030,SGM42403Q,SGM42553,SGM61032,SGM61031,74HC165,SGM62116,SGM8953-1,SGM62118,SGM8953-2,SGM62117,SGM8708,SGM8709,SGM4075-2,SGM3140B,SGM61040,SGM4075-1,SGM42544,SGM7300A,SGM7300B,SGM42541,SGM42540,SGM8951,SGM8952,SGM8710,SGM4590,SGM5200,SGM38045,SGM38042,SGM6533,SGM8711,SGM8712,SGM8955,SGM38046,SGM8956,SGM2053S,SGM8199L2,LM2904,SGM8199L1,SGM41002,SGM8968-4,SGM8968-2,LM2902,SGM8968-1,SGM8740,SGM8741,SGM8742,SGM2077A,SGM8743,SGM2077B,SGM8263-1,SGM8748,SGM8263-2,SGM8417-1,SGM8749,SGM12CB1A5,SGM8744,SGM40666B,SGM8745,SGM11104S,SGM40666A,SGM8746,SGM8747,SGM41513D,SGM41513A,SGM42561,SGM42560,SGM8957-1,SGM8957-2,SGM42562,SGM5208-14,SGM5223,SGM48018C,SGM11102F,SGM11102G,SGM41512A,SGM37603A,SGM8521,SGM8522,SGM11102S,SGM33685A,SGM5018,SGM33685B,SGM33685C,SGM8524,SGM8604-1,SGM11103E,SGM8604-5,SGM8193A3,SGM11103F,SGM8604-2,SGM8193A2,SGM48019C,SGM8604-3,SGM8193A1,SGM8193A0,SGM37604A,SGM8751,SGM11103S,SGM41007,SGM41008,SGM6332,SGM8750,FT2830P,SGM11212M,SGM41280,SGM41281,SGM41283,SGM5353-16,SGM37891A,SGM41285,SGM41286,SGM7SZ244S,SGM8542,SGM51652H8,SGM8543,SGM8301,SGM8544,SGM8302,SGM8545,SGM51652H4,SGM8541,SGM8429C-4,SGM8304,SGM8607-2,SGM37892A,SGM13003A,SGM8531,SGM8773,SGM8532,SGM8534,SGM8770,SGM8771,SGM8772,SGM8535,SGM8536,SGM8537,SGM12024A,SGM8538,SGM65230,SGM37893A,SGM65231,SGM65232,SGM8969-2,SGM8969-1,SGM13002A,SGM2035C,SGM7232,SGM9128YP,SGM41291,SGM2036S,74LVC1G32Q,SGM13001C,SGM13001B,74LVC138,SGM2581E,SGM8958-2,SGM41295,SGM13001A,SGM8958-1,SGM7222,SGM6132,SGM8554,SGM7223,SGM8555,SGM7224,SGM6130,SGM8556,SGM2581C,SGM8551,SGM7220,SGM2581A,SGM8552,SGM7226,SGM7227,SGM7228,SGM7229,SGM44599,SGM8581,SGM8713A-1,SGM8582,SGM6613A,SGM8584,SGM832B,SGM41282C,SGM832A,SGM8714B-1,SGM8924A,SGM811C,SGM5355-16,SGM7SZ19,74LVC1G125,SGM48535B,SGM89000,SGM7SZ14,SGM811B,SGM48535A,SGM48752X,SGM431VB,SGM2560A,SGM37603,SGM2560B,SGM6611C,SGM15CB1A4,SGM810B,SGM41280A,SGM8591,SGM8592,SGM48753X,SGM9203,SGM6612A,SGM8594,SGM8922A,SGM4T245,SGM48753,SGM48754,SGM48755,SGM48756,SGM51242R8,SGM48757,SCM40668,SGM813B,SGM48759,74AVC4T245,SGM8140,SGM8141,SGM48751,SGM449,SGM48752,SGMNQ07430,SGMPM21330,SGM48510,SGM458,SGM3785S,SGM37864,SGM61720,SGM459,SGM37863,SGM457,SGM8142,SGM452,SGM450,SGM451,SGM05UB1B3,SGM37862,SGM37861,SGM05CB1A8,SGM05CB1A7,SGM812B,SGM05CB1A4,74GTL2005,SGM25881,SGM447,SGM448,SGM446,SGM7SZ244,SGM8478-1C,SGM51242R4,SGM8139,SGM51242R2,SGM3705,SGM48536,SGM48537,SGM48538,SGM48539,SGM5351-16,SGM2588G,SGM2588E,SGM2588K,SGM3712,SGM3713,SGM2588C,SGM3710,SGM3711,SGM2588A,SGM48522,SGM48523,SGM48525,SGM48526,SGM48760,SGMNQ07440,SGM48520,SGM48521,SGM8557-5,SGM71XX,SGM706B,SGM460,SGM3701,SGM3700,SGM3727,SGM3741B,SGM3725,SGM3726,SGMOP07,SGM898,SGM899,SGM896,SGM897,SGM895,SGM4823,SGM2566B,SGM3735,SGM3732,SGM4822,SGM2566A,SGM3716,SGM3740B,SGM48544,SGM4806,SGM3717,SGM48545,SGM3714,SGM3715,SGM4809,SGM4807,SGM3718,SGM4808,SGM3719,74LVC157,SGM48780,SGM48540,SGM48541,SGM48542,SGM48543,SGM37898,SGM51652H,SGM51652D,SGM3720,SGM37891,SGM4812,SGM37892,SGM4810,SGM37895,SGM3749,SGM3747,SGM3748,SGM72204A,SGMNQ40430,SGM

选型指南 - SGMICRO - 2024/6/11 PDF 英文下载

SGMICRO-TI/ADI/MAXIM/MPS/SILERGY/ST等信号链电源芯片对照表

描述- 圣邦微SGMICRO与TI/ADI/MAXIM/LT/Onsemi/ST/Microchip/Nexperia/MPS/TOSHIBA/ROHM/RICHTEK/SILERGY/ABLIC/Renesas/Diodes/NXP/NJM/Infineon/Allegro 等品牌的信号链、电源芯对照表。

型号- SY8388,SN74HC541,A3981,IR44273,74AVC8T245Q,TS3A24159,TS3A24157,FAN3100,SLG88103,ADA4622-2,SLG88104,ADA4622-1,SGM2560,NA199,SGM2564,TSL6002,LMR23620,SGM48017C,LM431,FAN49103,MAX4282,SGM61220,BD9A201,74HC595,TLV3542,TLV3541,TS3A4751,TLV522,LMR23630,FAN53611,TC7SZ14FU,74LCX04,NCS21803,HCF4051,NCS21801,HCF4052,74LCX08,HCF4053,TSC214I,TLV3544,LMP2022,TSB611,NL27WZ04,SGM2588,FAN53601,SN74HC573,SN74HC574,INA333,TSU101,TSC213I,TSU102,NTMFS4C10N,UCC27531-Q1,TSU104,RT8293,74HC573,74HC574,SGM621,RT8290,SGM41600,TSB621,SGM620,SGM2572,SGM41603,SGM2571,SGM2576,SGM2575,SGM2578,SGM8T245S,RT8296,NL17SG07,SGM8557-1,TSU111,SGM8557-2,TSU112,ESD103-B1-02,INA321,TLV2242,TLV2241,SGM2205-12XK3G,ISL28118,OPA2277,BU30TD2,LM5109,BQ25619,SGM48013C,BQ25618,INA317,BQ25611,SGM62110,SGM62112,FSA4157,TPS76933,SGM2593,XB6091IS,BQ25601,TPS76950,BQ25600,SGM61230,TXS0104,TXS0102,SGM61232,SGM61234,TLV8801,TXS0101,SGM61233,74HC123,SGM5349-16,TLV62084,SGM431V,LTC2054,TPS51200,LTC2050,TLV8812,TLV8811,SGM61235,TLV8802,RT8253,BD9D323,BD9D322,AD5541,PMPB27EP,TPS54302,SGM4553YXET,LM7322,SGM8706,LM7321,SGM8707,SGM8701,MAX4664,LPV7215,SGM12UB1D2,AP2191,SGM3001,SGM42513,74LVC245A,SGM3005,TPS61099,SGM3002,SGM8276-2,TPS7A8300,SGMOP17C,TPS2553,ISL28130,TPS2556,TPS2557,SGM42403Q,SGM42553,BD6222,SGM8255B-2,ISL28134,74AHC1G08GV,TPS2551,74HC165,SGM62116,SGM62118,SGM62117,TPS3852-Q1,MAX4684,74HC164,AP2172,A3916,AP2171,TPS560430,A3918,BQ25638,SGM8709,U74LVC126,MP8676,SGM61280,MCP6V16,SGM42544,NCP718,LMX331,LMR36520,LM27761,TC7SZ32FU,SN74LVTH162373,ADM708,ADM707,SGM38042,SGM38046,TPS54340,MAX4230,TPS3823,LM2904,TC74VHC138,LM2902,LM2903,SGM8740,SGM2077A,SGM8742,SGM2077B,SGM8743,PESD5V0F1BSF,SGM41515A,MIC5209,LPV802,LPV801,SGM8748,SGM8749,NLAS44599,TPS54336,SGM40666A,SGM8746,TC74VCX16245,TPS54331,74LCX32,TPS54335,SGM41513D,SGM41513A,MCP6406,FTL75939,OPA548,SGM8957-1,MCP6402,SGM8957-2,TLV6208,SGM5223,MAX4232,TC74LCX16244,MAX4231,TPS3808,SN74LVC2T45,OPA2333P,MAX4236,SGM8551XN,TPS3840,TPS54320,SGM48018C,OPA990,RT4730,SGM41512A,SGM8745X,SN74AHC1,MAX9938,74LVTN16244,74LVTN16245,LPV821,SGM48019C,MCP6V52,MCP6V51,RT4723,OPA2210,TLV755P,SN74AC244,MCP6V54,AW2027,SGM8604-2XTDU8G,SGM8750,LPV812,LPV811,AD8534,SGM41283,SGM5353-16,AP2120,AD8539,AD8538,74LVC125,MCP6V69,74LVC126,SGM41285,DRV8313,MCP6V67,SN74LVC2G66,SGM7SZ244S,CAT4104,TS321,SGM8429C-4,AD5593R,SGM61430A,MP28373,MP5121,TMP108,74LVT16373,SGM8304,MAX40078,AD8541,74LVT16374,MCP6442,TMP103,TMP102,MP9943,MP9942,AP2112,MCP6V79,NCV890100,SGM13003A,MCP6V76,STSPIN250,MCP6V77,74LVTH125,SGM8770,AP2114,SGM38042B-1,LM2841,AD8513,AD621,AD620,NCS20034,SGM65230,NCS20032,AD623,AD8515,SGM65231,AD627,TC7SPN334,SGM13002A,SGM8477-1,SGM2035C,SGM41291,SGM2036S,MCP6V96,TUSB320,74LVC138,SGM7SZ245S,SGM8958-2,SGM41296,SN74CBT3245,MP9928,SGM41298,SGM8958-1,SGM6132,MAX4736,SGM6130,AD8532,AD8531,MAX4730,TPS3422,SGM833A,MCP6472,SGM833B,TLV1702,SGM7SZ32,SQ27403,MC74LVC74,TPS3420,TPS3421,TP2011,SGM2037H,MUX36S08,BISS0002,MC74AHC08,74LVC373A,TPS2595XXDSG,MCP6001,TPS3895,AD8502,TPS3896,TPS3897,AD8500,MCP6002,TPS3898,AP2151,SGM41282C,TPS3899,AD8506,AD8505,TLV7021,SGM832A,TP2025,MC33074,TP2021,MCP6004,MCP6006,LT7183,74LVC374A,AP2141,SN74LVC2G04,MCP6492,74LVC1G126,74LVC1G125,SGM48535B,SGM7SZ14,SGM48535A,SGM48752X,TPS2596,BU28TD2WNVX,AS179,XC6201,SGM15CB1A4,XC6206,TC7WZ04,SN74LVC2G14,MCP6022,SGM2210P,SGM7SZ08,MCP6024,SGM834A,SN74LVC2G17,MCP6021,SGM834B,SGM7SZ04,MP2497,SGM7SZ00,IRL44273LPBF,SGM48753X,SGM48754X,AD5592R,TLV61046A,TPS7A8400,SGM48753,SY8301,SGM48754,SQ24335,SGM2211S,SGM48757,ISL21080,SGM48759,SY8303,MCP6032,MCP6031,SGM48751,SGM48752,SGMNQ07430,SGM61720,TSV911,TSV912,TSV914,SN74AVC16T245,MP2490,SGM05UB1B3,LPV324,OPA4379,OPA4374,HD3SS3412,MCP6044,OPA4376,OPA2192,MCP6041,74VHC244,LMR16030,74AHCT595,APD7118,OPA2197,TPS62730,MCP6042,OPA2196,SN74AVC8T245,SN74LVC157,OPA2191,ADG509,ADG508,SGM8478-1C,FSA2457,TMUX415,TC7SZ00,LM1117,AD8599,TPS62743,TSV6192,SN74LVC125,SGM706S,SN74LVC126,RT6160,TPS76901,TC7SZ07,SGM2564A,TLV707P,NTMFS4C06N,MP2451,TS393,LMH6643,TC74VCX164245,SN74LVC138,SGM48760,SGM25662,MIC708,MCP6061,MP2460,LME49726,RT6150,MIC706,SN74AHCT86,MCP6074,TC7SH125F,STSPIN220,APD196,SGMOP07,74HC541,TC7SET08,LMC7211,BQ25890H,MAX706,MAX9119,MAX708,MCP6071,SGM2566C,74AHC573D,TC7SZ32,BU33TD2,74LVC157,YDA145,BD9G341,SGM2567S,NJMOP2277,INA828,LPV358,NCP382,NE5532,SGM2217Q,LMG1025-Q1,NCV6324,SGMNQ40430,NCV6334,SGM48536BQ,SGM21102G,74AHCT86,BGA524N6,SGM21102C,FSA2466,SGM21102B,INA818,SGM21102A,SGM05FB1E2,SN74AHC244,TLV74118,TC7SZ32F,NC7WZ04,74AVC8T245BQ,TSV991,TSV992,TSV994,SGM3851A,SGM48536CQ,TC913,74AHC244,AD8571,74AVC2T45,SGM2521A,TLV74128,SN74LVC541,AZ1117,LMV881,BU28TD2,MAX14589,TLV2316,SGM61330,SGM724,TS5V330,SGM5209-14,74LV541A,SGM3758,NJU7076,MAX4163,MAX4162,PESD15VW1BCSF,TLV74133,TPS25921A,OP213,TLV74130,SGM722,TLV2333,SGM723,SGM721,SGM8610-2,NLAS3899,OPA2140,EL5420,MAX4174,MAX4173,SGM15UB1E2,TC7SH126FU,SGM41100A,SGM61310,SKY13351,A4980,SGM41100V,SGM61306,SGM61305,SGM61308,SGM61307,SGM8262-2,TC7PZ14,SGM3795,74LCX126,74LCX125,74LVC541A,SGM3799,SA4159

对照表 - SGMICRO

SGMICRO线性稳压器选型表

SGMICRO线性稳压器提供高可靠性LDO和高精度LDO；最低0.5V最高36V输入电压，最大输出3A大电流，多固定输出电压与可调输出电压，支持负压降压。

产品型号	品类	VOUT(V)	VIN (Min)(V)	VIN (Max)(V)	IOUT(mA)	DropoutVoltage(mV)	PSRR (dB)	Package
SGM2300	High Reliability LDOs	1.5, 1.8, 2.5, 2.8, 3.0, 3.3, 3.6, 5.0, Adj	4	18	50	1750	47	SOT-23-5 SOT-23

选型表 - SGMICRO 立即选型

SGM2208XTDF12G/TR PcbLib & SchLib & IntLib

型号- SGM2208XTDF12G/TR

CAD模型库 - SGMICRO - 2024-06-17 RAR 英文下载

SGM2208 3A, Low Noise, Adjustable Output with Single Resistor and Low Dropout Regulator

型号- SGM2208,SGM2208XPTS16G/TR,SGM2208XO5G/TR,SGM2208XTDF12G/TR

数据手册 - SGMICRO - REV.A.3 - SEPTEMBER 2022 PDF 英文下载查看更多版本

【应用】低压差线性稳压器SGM2208XPTS16G/TR应用在小基站RRU，输出电流3A，输入电压最高达24V

在某RRU产品的设计中需要用到一颗负载3A的LDO来设计主控供电电路，要求输入电压最高可以达到24V等。推荐圣邦微的低压差线性稳压器SGM2208XPTS16G/TR用在RRU的设计中，具有低噪声、低损耗等特点。

应用方案发布时间 : 2022-08-19

SGM2208XO5G/TR PcbLib & SchLib & IntLib

型号- SGM2208XO5G/TR

CAD模型库 - SGMICRO - 2024/3/1 RAR 英文下载

SGM DFAE Training--Charger

型号- SGM41563,SGM41522,SGM41566,SGM7SZ32,SGM41562B,SGM48751,SGM724,SGM41562,SGM41516,SGM41518,SGM41519,SGM41512,SGM41513,SGM4056X,SGM2203,SGM61060,SGM41513D,SGM41510,SGM41513A,SGM41511,SGM61020,SGM722,SGM324,SGM4056,SGM8770,SGM4890,SGM803B,SGM41541,SGM41542,SGM41543,SGM61230,SGM40666AS,SGM358,SGM42505,SGM3752,SGM2225,SGM2036S,SGM7SZ08,SGM7SZ04,SGM41523B,SGM41523C,SGM41600A,SGM41523A,SGM42500,SGM41570,SGM41523D,SGM41573,SGM40561,SGM41527,SGM41528,SGM41523,SGM2593D,SGM41600,SGM41524,SGM8199,SGM41526,SGM2536

商品及供应商介绍 - SGMICRO - 2023/3/25 PDF 中文下载