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ZHCSCN3B June 2014 – March 2018 LM46000

PRODUCTION DATA.

封装选项

机械数据 (封装 | 引脚)

PWP|16
- MPDS371A

散热焊盘机械数据 (封装 | 引脚)

PWP|16
- PPTD297B

订购信息

8.2 Typical Applications

The LM46000 only requires a few external components to convert from a wide range of supply voltage to output voltage. Figure 44 shows a basic schematic when BIAS is connected to V_OUT . This is recommended for V_OUT ≥ 3.3 V. For V_OUT< 3.3 V, connect BIAS to ground, as shown in Figure 45.

Figure 44. LM46000 Basic Schematic for
V_OUT ≥ 3.3 V, Tie BIAS to V_OUT

Figure 45. LM46000 Basic Schematic for
V_OUT< 3.3 V, Tie BIAS to Ground

The LM46000 also integrates a full list of optional features to aid system design requirements, such as precision enable, V_CC UVLO, programmable soft start, output voltage tracking, programmable switching frequency, clock synchronization and power-good indication. Each application can select the features for a more comprehensive design. A schematic with all features utilized is shown in Figure 46.

Figure 46. LM46000 Schematic With All Features

The external components must fulfill the needs of the application, but also the stability criteria of the device control loop. The LM46000 is optimized to work within a range of external components. Inductance and capacitance of the LC output filter must be considered in conjunction, creating a double pole, responsible for the corner frequency of the converter. Table 2 can be used to simplify the output filter component selection.

Table 2. L, C_OUT and C_FF Typical Values

F_S (kHz)	L (µH)⁽¹⁾	C_OUT (µF)⁽²⁾	C_FF (pF)⁽³⁾⁽⁴⁾	R_T (kΩ)	R_FBB (kΩ)⁽³⁾⁽⁴⁾
V_OUT = 1 V
200	22	500	none	200	100
500	10	330	none	80.6 or open	100
1000	4.8	180	none	39.2	100
2200	2.2	100	none	17.8	100
V_OUT = 3.3 V
200	68	220	44	200	442
500	27	100	33	80.6 or open	442
1000	15	47	18	39.2	442
2200	6.8	27	12	17.8	442
V_OUT = 5 V
200	100	150	66	200	249
500	44	66	33	80.6 or open	249
1000	22	33	22	39.2	249
2200	10	22	18	17.8	249
V_OUT = 12 V
200	150	33	see note ⁽⁵⁾	200	93.1
500	56	22	47	80.6 or open	93.1
1000	27	15	33	39.2	93.1
V_OUT = 24 V
200	270	22	see note ⁽⁵⁾	200	44.2
500	120	15	see note ⁽⁵⁾	80.6 or open	44.2
1000	56	10	see note ⁽⁵⁾	39.2	44.2

(1) Inductor values are calculated based on typical V_IN = 24 V. For V_OUT of 24 V, V_IN = 48 V

(2) All the C_OUT values are after derating. Add more when using ceramics.

(3) R_FBT = 0 Ω for V_OUT = 1 V. R_FBT = 1 MΩ for all other V_OUT settings.

(4) For designs with R_FBT other than 1 MΩ, adjust C_FF such that (C_FF × R_FBT) is unchanged and adjust R_FBB such that (R_FBT / R_FBB) is unchanged.

(5) High ESR C_OUT givse enough phase boost, and C_FF not needed.